BitTorious volunteer: server-side extensions for centrally-managed volunteer storage in BitTorrent swarms.

PubMed

Lee, Preston V; Dinu, Valentin

2015-11-04

Our publication of the BitTorious portal [1] demonstrated the ability to create a privatized distributed data warehouse of sufficient magnitude for real-world bioinformatics studies using minimal changes to the standard BitTorrent tracker protocol. In this second phase, we release a new server-side specification to accept anonymous philantropic storage donations by the general public, wherein a small portion of each user's local disk may be used for archival of scientific data. We have implementated the server-side announcement and control portions of this BitTorrent extension into v3.0.0 of the BitTorious portal, upon which compatible clients may be built. Automated test cases for the BitTorious Volunteer extensions have been added to the portal's v3.0.0 release, supporting validation of the "peer affinity" concept and announcement protocol introduced by this specification. Additionally, a separate reference implementation of affinity calculation has been provided in C++ for informaticians wishing to integrate into libtorrent-based projects. The BitTorrent "affinity" extensions as provided in the BitTorious portal reference implementation allow data publishers to crowdsource the extreme storage prerequisites for research in "big data" fields. With sufficient awareness and adoption of BitTorious Volunteer-based clients by the general public, the BitTorious portal may be able to provide peta-scale storage resources to the scientific community at relatively insignificant financial cost.

Experimental bit commitment based on quantum communication and special relativity.

PubMed

Lunghi, T; Kaniewski, J; Bussières, F; Houlmann, R; Tomamichel, M; Kent, A; Gisin, N; Wehner, S; Zbinden, H

2013-11-01

Bit commitment is a fundamental cryptographic primitive in which Bob wishes to commit a secret bit to Alice. Perfectly secure bit commitment between two mistrustful parties is impossible through asynchronous exchange of quantum information. Perfect security is however possible when Alice and Bob split into several agents exchanging classical and quantum information at times and locations suitably chosen to satisfy specific relativistic constraints. Here we report on an implementation of a bit commitment protocol using quantum communication and special relativity. Our protocol is based on [A. Kent, Phys. Rev. Lett. 109, 130501 (2012)] and has the advantage that it is practically feasible with arbitrary large separations between the agents in order to maximize the commitment time. By positioning agents in Geneva and Singapore, we obtain a commitment time of 15 ms. A security analysis considering experimental imperfections and finite statistics is presented.

Specifying real-time systems with interval logic

NASA Technical Reports Server (NTRS)

Rushby, John

1988-01-01

Pure temporal logic makes no reference to time. An interval temporal logic and an extension to that logic which includes real time constraints are described. The application of this logic by giving a specification for the well-known lift (elevator) example is demonstrated. It is shown how interval logic can be extended to include a notion of process. How the specification language and verification environment of EHDM could be enhanced to support this logic is described. A specification of the alternating bit protocol in this extended version of the specification language of EHDM is given.

Practical quantum key distribution protocol without monitoring signal disturbance.

PubMed

Sasaki, Toshihiko; Yamamoto, Yoshihisa; Koashi, Masato

2014-05-22

Quantum cryptography exploits the fundamental laws of quantum mechanics to provide a secure way to exchange private information. Such an exchange requires a common random bit sequence, called a key, to be shared secretly between the sender and the receiver. The basic idea behind quantum key distribution (QKD) has widely been understood as the property that any attempt to distinguish encoded quantum states causes a disturbance in the signal. As a result, implementation of a QKD protocol involves an estimation of the experimental parameters influenced by the eavesdropper's intervention, which is achieved by randomly sampling the signal. If the estimation of many parameters with high precision is required, the portion of the signal that is sacrificed increases, thus decreasing the efficiency of the protocol. Here we propose a QKD protocol based on an entirely different principle. The sender encodes a bit sequence onto non-orthogonal quantum states and the receiver randomly dictates how a single bit should be calculated from the sequence. The eavesdropper, who is unable to learn the whole of the sequence, cannot guess the bit value correctly. An achievable rate of secure key distribution is calculated by considering complementary choices between quantum measurements of two conjugate observables. We found that a practical implementation using a laser pulse train achieves a key rate comparable to a decoy-state QKD protocol, an often-used technique for lasers. It also has a better tolerance of bit errors and of finite-sized-key effects. We anticipate that this finding will give new insight into how the probabilistic nature of quantum mechanics can be related to secure communication, and will facilitate the simple and efficient use of conventional lasers for QKD.

Purification of Logic-Qubit Entanglement.

PubMed

Zhou, Lan; Sheng, Yu-Bo

2016-07-05

Recently, the logic-qubit entanglement shows its potential application in future quantum communication and quantum network. However, the entanglement will suffer from the noise and decoherence. In this paper, we will investigate the first entanglement purification protocol for logic-qubit entanglement. We show that both the bit-flip error and phase-flip error in logic-qubit entanglement can be well purified. Moreover, the bit-flip error in physical-qubit entanglement can be completely corrected. The phase-flip in physical-qubit entanglement error equals to the bit-flip error in logic-qubit entanglement, which can also be purified. This entanglement purification protocol may provide some potential applications in future quantum communication and quantum network.

Security of two-state and four-state practical quantum bit-commitment protocols

NASA Astrophysics Data System (ADS)

Loura, Ricardo; Arsenović, Dušan; Paunković, Nikola; Popović, Duška B.; Prvanović, Slobodan

2016-12-01

We study cheating strategies against a practical four-state quantum bit-commitment protocol [A. Danan and L. Vaidman, Quant. Info. Proc. 11, 769 (2012)], 10.1007/s11128-011-0284-4 and its two-state variant [R. Loura et al., Phys. Rev. A 89, 052336 (2014)], 10.1103/PhysRevA.89.052336 when the underlying quantum channels are noisy and the cheating party is constrained to using single-qubit measurements only. We show that simply inferring the transmitted photons' states by using the Breidbart basis, optimal for ambiguous (minimum-error) state discrimination, does not directly produce an optimal cheating strategy for this bit-commitment protocol. We introduce a strategy, based on certain postmeasurement processes and show it to have better chances at cheating than the direct approach. We also study to what extent sending forged geographical coordinates helps a dishonest party in breaking the binding security requirement. Finally, we investigate the impact of imperfect single-photon sources in the protocols. Our study shows that, in terms of the resources used, the four-state protocol is advantageous over the two-state version. The analysis performed can be straightforwardly generalized to any finite-qubit measurement, with the same qualitative results.

Purification of Logic-Qubit Entanglement

PubMed Central

Zhou, Lan; Sheng, Yu-Bo

2016-01-01

Recently, the logic-qubit entanglement shows its potential application in future quantum communication and quantum network. However, the entanglement will suffer from the noise and decoherence. In this paper, we will investigate the first entanglement purification protocol for logic-qubit entanglement. We show that both the bit-flip error and phase-flip error in logic-qubit entanglement can be well purified. Moreover, the bit-flip error in physical-qubit entanglement can be completely corrected. The phase-flip in physical-qubit entanglement error equals to the bit-flip error in logic-qubit entanglement, which can also be purified. This entanglement purification protocol may provide some potential applications in future quantum communication and quantum network. PMID:27377165

Reexamination of quantum bit commitment: The possible and the impossible

DOE Office of Scientific and Technical Information (OSTI.GOV)

D'Ariano, Giacomo Mauro; Kretschmann, Dennis; Institut fuer Mathematische Physik, Technische Universitaet Braunschweig, Mendelssohnstrasse 3, 38106 Braunschweig

2007-09-15

Bit commitment protocols whose security is based on the laws of quantum mechanics alone are generally held to be impossible. We give a strengthened and explicit proof of this result. We extend its scope to a much larger variety of protocols, which may have an arbitrary number of rounds, in which both classical and quantum information is exchanged, and which may include aborts and resets. Moreover, we do not consider the receiver to be bound to a fixed 'honest' strategy, so that 'anonymous state protocols', which were recently suggested as a possible way to beat the known no-go results, aremore » also covered. We show that any concealing protocol allows the sender to find a cheating strategy, which is universal in the sense that it works against any strategy of the receiver. Moreover, if the concealing property holds only approximately, the cheat goes undetected with a high probability, which we explicitly estimate. The proof uses an explicit formalization of general two-party protocols, which is applicable to more general situations, and an estimate about the continuity of the Stinespring dilation of a general quantum channel. The result also provides a natural characterization of protocols that fall outside the standard setting of unlimited available technology and thus may allow secure bit commitment. We present such a protocol whose security, perhaps surprisingly, relies on decoherence in the receiver's laboratory.« less

Demonstration of a quantum error detection code using a square lattice of four superconducting qubits

PubMed Central

Córcoles, A.D.; Magesan, Easwar; Srinivasan, Srikanth J.; Cross, Andrew W.; Steffen, M.; Gambetta, Jay M.; Chow, Jerry M.

2015-01-01

The ability to detect and deal with errors when manipulating quantum systems is a fundamental requirement for fault-tolerant quantum computing. Unlike classical bits that are subject to only digital bit-flip errors, quantum bits are susceptible to a much larger spectrum of errors, for which any complete quantum error-correcting code must account. Whilst classical bit-flip detection can be realized via a linear array of qubits, a general fault-tolerant quantum error-correcting code requires extending into a higher-dimensional lattice. Here we present a quantum error detection protocol on a two-by-two planar lattice of superconducting qubits. The protocol detects an arbitrary quantum error on an encoded two-qubit entangled state via quantum non-demolition parity measurements on another pair of error syndrome qubits. This result represents a building block towards larger lattices amenable to fault-tolerant quantum error correction architectures such as the surface code. PMID:25923200

Demonstration of a quantum error detection code using a square lattice of four superconducting qubits.

PubMed

Córcoles, A D; Magesan, Easwar; Srinivasan, Srikanth J; Cross, Andrew W; Steffen, M; Gambetta, Jay M; Chow, Jerry M

2015-04-29

The ability to detect and deal with errors when manipulating quantum systems is a fundamental requirement for fault-tolerant quantum computing. Unlike classical bits that are subject to only digital bit-flip errors, quantum bits are susceptible to a much larger spectrum of errors, for which any complete quantum error-correcting code must account. Whilst classical bit-flip detection can be realized via a linear array of qubits, a general fault-tolerant quantum error-correcting code requires extending into a higher-dimensional lattice. Here we present a quantum error detection protocol on a two-by-two planar lattice of superconducting qubits. The protocol detects an arbitrary quantum error on an encoded two-qubit entangled state via quantum non-demolition parity measurements on another pair of error syndrome qubits. This result represents a building block towards larger lattices amenable to fault-tolerant quantum error correction architectures such as the surface code.

BitPredator: A Discovery Algorithm for BitTorrent Initial Seeders and Peers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borges, Raymond; Patton, Robert M; Kettani, Houssain

2011-01-01

There is a large amount of illegal content being replicated through peer-to-peer (P2P) networks where BitTorrent is dominant; therefore, a framework to profile and police it is needed. The goal of this work is to explore the behavior of initial seeds and highly active peers to develop techniques to correctly identify them. We intend to establish a new methodology and software framework for profiling BitTorrent peers. This involves three steps: crawling torrent indexers for keywords in recently added torrents using Really Simple Syndication protocol (RSS), querying torrent trackers for peer list data and verifying Internet Protocol (IP) addresses from peermore » lists. We verify IPs using active monitoring methods. Peer behavior is evaluated and modeled using bitfield message responses. We also design a tool to profile worldwide file distribution by mapping IP-to-geolocation and linking to WHOIS server information in Google Earth.« less

Achieving the Holevo bound via a bisection decoding protocol

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rosati, Matteo; Giovannetti, Vittorio

2016-06-15

We present a new decoding protocol to realize transmission of classical information through a quantum channel at asymptotically maximum capacity, achieving the Holevo bound and thus the optimal communication rate. At variance with previous proposals, our scheme recovers the message bit by bit, making use of a series of “yes-no” measurements, organized in bisection fashion, thus determining which codeword was sent in log{sub 2} N steps, N being the number of codewords.

Quantum Authencryption with Two-Photon Entangled States for Off-Line Communicants

NASA Astrophysics Data System (ADS)

Ye, Tian-Yu

2016-02-01

In this paper, a quantum authencryption protocol is proposed by using the two-photon entangled states as the quantum resource. Two communicants Alice and Bob share two private keys in advance, which determine the generation of two-photon entangled states. The sender Alice sends the two-photon entangled state sequence encoded with her classical bits to the receiver Bob in the manner of one-step quantum transmission. Upon receiving the encoded quantum state sequence, Bob decodes out Alice's classical bits with the two-photon joint measurements and authenticates the integrity of Alice's secret with the help of one-way hash function. The proposed protocol only uses the one-step quantum transmission and needs neither a public discussion nor a trusted third party. As a result, the proposed protocol can be adapted to the case where the receiver is off-line, such as the quantum E-mail systems. Moreover, the proposed protocol provides the message authentication to one bit level with the help of one-way hash function and has an information-theoretical efficiency equal to 100 %.

Guidance Material for Mode S-Specific Protocol Application Avionics

DTIC Science & Technology

2007-06-04

the high-order 28 bits of each register are used to specify the configuration state of uplink MSP channels, while the low -order 28 bits of each...TID field contains the 24-bit Mode S address of the threat (when the threat is Mode S equipped). The low -order 2 bits of the TID field are cleared. If...the register should be sufficient to ensure that the maximum latency of each data value is not exceeded. (Note: If all five of the status fields in the

Anti-Noise Bidirectional Quantum Steganography Protocol with Large Payload

NASA Astrophysics Data System (ADS)

Qu, Zhiguo; Chen, Siyi; Ji, Sai; Ma, Songya; Wang, Xiaojun

2018-06-01

An anti-noise bidirectional quantum steganography protocol with large payload protocol is proposed in this paper. In the new protocol, Alice and Bob enable to transmit classical information bits to each other while teleporting secret quantum states covertly. The new protocol introduces the bidirectional quantum remote state preparation into the bidirectional quantum secure communication, not only to expand secret information from classical bits to quantum state, but also extract the phase and amplitude values of secret quantum state for greatly enlarging the capacity of secret information. The new protocol can also achieve better imperceptibility, since the eavesdropper can hardly detect the hidden channel or even obtain effective secret quantum states. Comparing with the previous quantum steganography achievements, due to its unique bidirectional quantum steganography, the new protocol can obtain higher transmission efficiency and better availability. Furthermore, the new algorithm can effectively resist quantum noises through theoretical analysis. Finally, the performance analysis proves the conclusion that the new protocol not only has good imperceptibility, high security, but also large payload.

Anti-Noise Bidirectional Quantum Steganography Protocol with Large Payload

NASA Astrophysics Data System (ADS)

Qu, Zhiguo; Chen, Siyi; Ji, Sai; Ma, Songya; Wang, Xiaojun

2018-03-01

An anti-noise bidirectional quantum steganography protocol with large payload protocol is proposed in this paper. In the new protocol, Alice and Bob enable to transmit classical information bits to each other while teleporting secret quantum states covertly. The new protocol introduces the bidirectional quantum remote state preparation into the bidirectional quantum secure communication, not only to expand secret information from classical bits to quantum state, but also extract the phase and amplitude values of secret quantum state for greatly enlarging the capacity of secret information. The new protocol can also achieve better imperceptibility, since the eavesdropper can hardly detect the hidden channel or even obtain effective secret quantum states. Comparing with the previous quantum steganography achievements, due to its unique bidirectional quantum steganography, the new protocol can obtain higher transmission efficiency and better availability. Furthermore, the new algorithm can effectively resist quantum noises through theoretical analysis. Finally, the performance analysis proves the conclusion that the new protocol not only has good imperceptibility, high security, but also large payload.

Comment on "Direct counterfactual transmission of a quantum state"

NASA Astrophysics Data System (ADS)

Vaidman, L.

2016-06-01

The protocol for counterfactual transmission of a qubit [Z.-H. Li et al., Phys. Rev. A 92, 052315 (2015), 10.1103/PhysRevA.92.052315] relies on the counterfactuality of transmissions of bit 1 and of bit 0. Since counterfactuality of transmission of bit 0 is not established, the claim of counterfactuality of transmission of a quantum state is not established too.

DDN (Defense Data Network) Protocol Handbook. Volume 2. DARPA Internet Protocols

DTIC Science & Technology

1985-12-01

header padding is used to ensure that the internet header ends on a 32 bit boundary. The padding is zero . 3.2. Discussion The implementation of a... zeros . The first of these would be interpreted as the end-of-options option, and the remainder as internet header padding , Every internet module must...several octets in length. The internet header Padding field is used to ensure that the data begins on 32 bit word boundary. The padding is zero

Practical quantum private query with better performance in resisting joint-measurement attack

NASA Astrophysics Data System (ADS)

Wei, Chun-Yan; Wang, Tian-Yin; Gao, Fei

2016-04-01

As a kind of practical protocol, quantum-key-distribution (QKD)-based quantum private queries (QPQs) have drawn lots of attention. However, joint-measurement (JM) attack poses a noticeable threat to the database security in such protocols. That is, by JM attack a malicious user can illegally elicit many more items from the database than the average amount an honest one can obtain. Taking Jacobi et al.'s protocol as an example, by JM attack a malicious user can obtain as many as 500 bits, instead of the expected 2.44 bits, from a 104-bit database in one query. It is a noticeable security flaw in theory, and would also arise in application with the development of quantum memories. To solve this problem, we propose a QPQ protocol based on a two-way QKD scheme, which behaves much better in resisting JM attack. Concretely, the user Alice cannot get more database items by conducting JM attack on the qubits because she has to send them back to Bob (the database holder) before knowing which of them should be jointly measured. Furthermore, JM attack by both Alice and Bob would be detected with certain probability, which is quite different from previous protocols. Moreover, our protocol retains the good characters of QKD-based QPQs, e.g., it is loss tolerant and robust against quantum memory attack.

Experimentally feasible quantum-key-distribution scheme using qubit-like qudits and its comparison with existing qubit- and qudit-based protocols

NASA Astrophysics Data System (ADS)

Chau, H. F.; Wang, Qinan; Wong, Cardythy

2017-02-01

Recently, Chau [Phys. Rev. A 92, 062324 (2015), 10.1103/PhysRevA.92.062324] introduced an experimentally feasible qudit-based quantum-key-distribution (QKD) scheme. In that scheme, one bit of information is phase encoded in the prepared state in a 2n-dimensional Hilbert space in the form (|i > ±|j >) /√{2 } with n ≥2 . For each qudit prepared and measured in the same two-dimensional Hilbert subspace, one bit of raw secret key is obtained in the absence of transmission error. Here we show that by modifying the basis announcement procedure, the same experimental setup can generate n bits of raw key for each qudit prepared and measured in the same basis in the noiseless situation. The reason is that in addition to the phase information, each qudit also carries information on the Hilbert subspace used. The additional (n -1 ) bits of raw key comes from a clever utilization of this extra piece of information. We prove the unconditional security of this modified protocol and compare its performance with other existing provably secure qubit- and qudit-based protocols on market in the one-way classical communication setting. Interestingly, we find that for the case of n =2 , the secret key rate of this modified protocol using nondegenerate random quantum code to perform one-way entanglement distillation is equal to that of the six-state scheme.

A study of high density bit transition requirements versus the effects on BCH error correcting coding

NASA Technical Reports Server (NTRS)

Ingels, F.; Schoggen, W. O.

1981-01-01

Several methods for increasing bit transition densities in a data stream are summarized, discussed in detail, and compared against constraints imposed by the 2 MHz data link of the space shuttle high rate multiplexer unit. These methods include use of alternate pulse code modulation waveforms, data stream modification by insertion, alternate bit inversion, differential encoding, error encoding, and use of bit scramblers. The psuedo-random cover sequence generator was chosen for application to the 2 MHz data link of the space shuttle high rate multiplexer unit. This method is fully analyzed and a design implementation proposed.

Unconditional security proof of a deterministic quantum key distribution with a two-way quantum channel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu Hua; Department of Mathematics and Physics, Hubei University of Technology, Wuhan 430068; Fung, Chi-Hang Fred

2011-10-15

In a deterministic quantum key distribution (DQKD) protocol with a two-way quantum channel, Bob sends a qubit to Alice who then encodes a key bit onto the qubit and sends it back to Bob. After measuring the returned qubit, Bob can obtain Alice's key bit immediately, without basis reconciliation. Since an eavesdropper may attack the qubits traveling on either the Bob-Alice channel or the Alice-Bob channel, the security analysis of DQKD protocol with a two-way quantum channel is complicated and its unconditional security has been controversial. This paper presents a security proof of a single-photon four-state DQKD protocol against generalmore » attacks.« less

Quantum private comparison protocol based on the entanglement swapping between χ ^+ state and W-Class state

NASA Astrophysics Data System (ADS)

Xu, Ling; Zhao, Zhiwen

2017-12-01

Quantum private comparison (QPC) protocol, including Alice, Bob and the third party Charlie, aims at comparing Alice and Bob's secret inputs correctly without leaking them. Firstly, χ ^+ state and W-Class state are used to conduct the entanglement swapping in this protocol. Either the basis {|φ ^± > ,|ψ ^± >} or the basis {|χ ^± > ,|ω ^± > } is chosen by Alice and Bob based on the predetermined value to measure the particle pairs. And three bits of secret inputs can be compared in this protocol in every comparison time, while most of previous QPC protocols can only compare one or two bits. The qubit efficiency of this protocol is 60% more than others, which are 50% at most. Secondly, if the eavesdropper intends to obtain the secret inputs, it is important and primary to get the measurement results of particle pairs. In this protocol, even if the eavesdropper gets the accurate particle pairs, he cannot get the right measurement results without the right basis. Finally, this protocol is analyzed to be able to defend the secret inputs against various kinds of attack.

Semi-counterfactual cryptography

NASA Astrophysics Data System (ADS)

Akshata Shenoy, H.; Srikanth, R.; Srinivas, T.

2013-09-01

In counterfactual quantum key distribution (QKD), two remote parties can securely share random polarization-encoded bits through the blocking rather than the transmission of particles. We propose a semi-counterfactual QKD, i.e., one where the secret bit is shared, and also encoded, based on the blocking or non-blocking of a particle. The scheme is thus semi-counterfactual and not based on polarization encoding. As with other counterfactual schemes and the Goldenberg-Vaidman protocol, but unlike BB84, the encoding states are orthogonal and security arises ultimately from single-particle non-locality. Unlike any of them, however, the secret bit generated is maximally indeterminate until the joint action of Alice and Bob. We prove the general security of the protocol, and study the most general photon-number-preserving incoherent attack in detail.

Faithful teleportation with partially entangled states

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gour, Gilad

2004-10-01

We write explicitly a general protocol for faithful teleportation of a d-state particle (qudit) via a partially entangled pair of (pure) n-state particles. The classical communication cost (CCC) of the protocol is log{sub 2}(nd) bits, and it is implemented by a projective measurement performed by Alice, and a unitary operator performed by Bob (after receiving from Alice the measurement result). We prove the optimality of our protocol by a comparison with the concentrate and teleport strategy. We also show that if d>n/2, or if there is no residual entanglement left after the faithful teleportation, the CCC of any protocol ismore » at least log{sub 2}(nd) bits. Furthermore, we find a lower bound on the CCC in the process transforming one bipartite state to another by means of local operation and classical communication.« less

Security of six-state quantum key distribution protocol with threshold detectors

PubMed Central

Kato, Go; Tamaki, Kiyoshi

2016-01-01

The security of quantum key distribution (QKD) is established by a security proof, and the security proof puts some assumptions on the devices consisting of a QKD system. Among such assumptions, security proofs of the six-state protocol assume the use of photon number resolving (PNR) detector, and as a result the bit error rate threshold for secure key generation for the six-state protocol is higher than that for the BB84 protocol. Unfortunately, however, this type of detector is demanding in terms of technological level compared to the standard threshold detector, and removing the necessity of such a detector enhances the feasibility of the implementation of the six-state protocol. Here, we develop the security proof for the six-state protocol and show that we can use the threshold detector for the six-state protocol. Importantly, the bit error rate threshold for the key generation for the six-state protocol (12.611%) remains almost the same as the one (12.619%) that is derived from the existing security proofs assuming the use of PNR detectors. This clearly demonstrates feasibility of the six-state protocol with practical devices. PMID:27443610

New PDC bit design reduces vibrational problems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mensa-Wilmot, G.; Alexander, W.L.

1995-05-22

A new polycrystalline diamond compact (PDC) bit design combines cutter layout, load balancing, unsymmetrical blades and gauge pads, and spiraled blades to reduce problematic vibrations without limiting drilling efficiency. Stabilization improves drilling efficiency and also improves dull characteristics for PDC bits. Some PDC bit designs mitigate one vibrational mode (such as bit whirl) through drilling parameter manipulation yet cause or excite another vibrational mode (such as slip-stick). An alternative vibration-reducing concept which places no limitations on the operational environment of a PDC bit has been developed to ensure optimization of the bit`s available mechanical energy. The paper discusses bit stabilization,more » vibration reduction, vibration prevention, cutter arrangement, load balancing, blade layout, spiraled blades, and bit design.« less

Traffic management mechanism for intranets with available-bit-rate access to the Internet

NASA Astrophysics Data System (ADS)

Hassan, Mahbub; Sirisena, Harsha R.; Atiquzzaman, Mohammed

1997-10-01

The design of a traffic management mechanism for intranets connected to the Internet via an available bit rate access- link is presented. Selection of control parameters for this mechanism for optimum performance is shown through analysis. An estimate for packet loss probability at the access- gateway is derived for random fluctuation of available bit rate of the access-link. Some implementation strategies of this mechanism in the standard intranet protocol stack are also suggested.

S-EMG signal compression based on domain transformation and spectral shape dynamic bit allocation

PubMed Central

2014-01-01

Background Surface electromyographic (S-EMG) signal processing has been emerging in the past few years due to its non-invasive assessment of muscle function and structure and because of the fast growing rate of digital technology which brings about new solutions and applications. Factors such as sampling rate, quantization word length, number of channels and experiment duration can lead to a potentially large volume of data. Efficient transmission and/or storage of S-EMG signals are actually a research issue. That is the aim of this work. Methods This paper presents an algorithm for the data compression of surface electromyographic (S-EMG) signals recorded during isometric contractions protocol and during dynamic experimental protocols such as the cycling activity. The proposed algorithm is based on discrete wavelet transform to proceed spectral decomposition and de-correlation, on a dynamic bit allocation procedure to code the wavelets transformed coefficients, and on an entropy coding to minimize the remaining redundancy and to pack all data. The bit allocation scheme is based on mathematical decreasing spectral shape models, which indicates a shorter digital word length to code high frequency wavelets transformed coefficients. Four bit allocation spectral shape methods were implemented and compared: decreasing exponential spectral shape, decreasing linear spectral shape, decreasing square-root spectral shape and rotated hyperbolic tangent spectral shape. Results The proposed method is demonstrated and evaluated for an isometric protocol and for a dynamic protocol using a real S-EMG signal data bank. Objective performance evaluations metrics are presented. In addition, comparisons with other encoders proposed in scientific literature are shown. Conclusions The decreasing bit allocation shape applied to the quantized wavelet coefficients combined with arithmetic coding results is an efficient procedure. The performance comparisons of the proposed S-EMG data compression algorithm with the established techniques found in scientific literature have shown promising results. PMID:24571620

Live chat alternative security protocol

NASA Astrophysics Data System (ADS)

Rahman, J. P. R.; Nugraha, E.; Febriany, A.

2018-05-01

Indonesia is one of the largest e-commerce markets in Southeast Asia, as many as 5 million people do transactions in e-commerce, therefore more and more people use live chat service to communicate with customer service. In live chat, the customer service often asks customers’ data such as, full name, address, e-mail, transaction id, which aims to verify the purchase of the product. One of the risks that will happen is sniffing which will lead to the theft of confidential information that will cause huge losses to the customer. The anticipation that will be done is build an alternative security protocol for user interaction in live chat by using a cryptographic algorithm that is useful for protecting confidential messages. Live chat requires confidentiality and data integration with encryption and hash functions. The used algorithm are Rijndael 256 bits, RSA, and SHA256. To increase the complexity, the Rijndael algorithm will be modified in the S-box and ShiftRow sections based on the shannon principle rule, the results show that all pass the Randomness test, but the modification in Shiftrow indicates a better avalanche effect. Therefore the message will be difficult to be stolen or changed.

Measurement-device-independent quantum key distribution for Scarani-Acin-Ribordy-Gisin 04 protocol

PubMed Central

Mizutani, Akihiro; Tamaki, Kiyoshi; Ikuta, Rikizo; Yamamoto, Takashi; Imoto, Nobuyuki

2014-01-01

The measurement-device-independent quantum key distribution (MDI QKD) was proposed to make BB84 completely free from any side-channel in detectors. Like in prepare & measure QKD, the use of other protocols in MDI setting would be advantageous in some practical situations. In this paper, we consider SARG04 protocol in MDI setting. The prepare & measure SARG04 is proven to be able to generate a key up to two-photon emission events. In MDI setting we show that the key generation is possible from the event with single or two-photon emission by a party and single-photon emission by the other party, but the two-photon emission event by both parties cannot contribute to the key generation. On the contrary to prepare & measure SARG04 protocol where the experimental setup is exactly the same as BB84, the measurement setup for SARG04 in MDI setting cannot be the same as that for BB84 since the measurement setup for BB84 in MDI setting induces too many bit errors. To overcome this problem, we propose two alternative experimental setups, and we simulate the resulting key rate. Our study highlights the requirements that MDI QKD poses on us regarding with the implementation of a variety of QKD protocols. PMID:24913431

Robust relativistic bit commitment

NASA Astrophysics Data System (ADS)

Chakraborty, Kaushik; Chailloux, André; Leverrier, Anthony

2016-12-01

Relativistic cryptography exploits the fact that no information can travel faster than the speed of light in order to obtain security guarantees that cannot be achieved from the laws of quantum mechanics alone. Recently, Lunghi et al. [Phys. Rev. Lett. 115, 030502 (2015), 10.1103/PhysRevLett.115.030502] presented a bit-commitment scheme where each party uses two agents that exchange classical information in a synchronized fashion, and that is both hiding and binding. A caveat is that the commitment time is intrinsically limited by the spatial configuration of the players, and increasing this time requires the agents to exchange messages during the whole duration of the protocol. While such a solution remains computationally attractive, its practicality is severely limited in realistic settings since all communication must remain perfectly synchronized at all times. In this work, we introduce a robust protocol for relativistic bit commitment that tolerates failures of the classical communication network. This is done by adding a third agent to both parties. Our scheme provides a quadratic improvement in terms of expected sustain time compared with the original protocol, while retaining the same level of security.

Single photon quantum cryptography.

PubMed

Beveratos, Alexios; Brouri, Rosa; Gacoin, Thierry; Villing, André; Poizat, Jean-Philippe; Grangier, Philippe

2002-10-28

We report the full implementation of a quantum cryptography protocol using a stream of single photon pulses generated by a stable and efficient source operating at room temperature. The single photon pulses are emitted on demand by a single nitrogen-vacancy color center in a diamond nanocrystal. The quantum bit error rate is less that 4.6% and the secure bit rate is 7700 bits/s. The overall performances of our system reaches a domain where single photons have a measurable advantage over an equivalent system based on attenuated light pulses.

Internet Protocol Security (IPSEC): Testing and Implications on IPv4 and IPv6 Networks

DTIC Science & Technology

2008-08-27

Message Authentication Code-Message Digest 5-96). Due to the processing power consumption and slowness of public key authentication methods, RSA ...MODP) group with a 768 -bit modulus 2. a MODP group with a 1024-bit modulus 3. an Elliptic Curve Group over GF[ 2n ] (EC2N) group with a 155-bit...nonces, digital signatures using the Digital Signature Algorithm, and the Rivest-Shamir- Adelman ( RSA ) algorithm. For more information about the

Enhancing user privacy in SARG04-based private database query protocols

NASA Astrophysics Data System (ADS)

Yu, Fang; Qiu, Daowen; Situ, Haozhen; Wang, Xiaoming; Long, Shun

2015-11-01

The well-known SARG04 protocol can be used in a private query application to generate an oblivious key. By usage of the key, the user can retrieve one out of N items from a database without revealing which one he/she is interested in. However, the existing SARG04-based private query protocols are vulnerable to the attacks of faked data from the database since in its canonical form, the SARG04 protocol lacks means for one party to defend attacks from the other. While such attacks can cause significant loss of user privacy, a variant of the SARG04 protocol is proposed in this paper with new mechanisms designed to help the user protect its privacy in private query applications. In the protocol, it is the user who starts the session with the database, trying to learn from it bits of a raw key in an oblivious way. An honesty test is used to detect a cheating database who had transmitted faked data. The whole private query protocol has O( N) communication complexity for conveying at least N encrypted items. Compared with the existing SARG04-based protocols, it is efficient in communication for per-bit learning.

Data Transfer Efficiency Over Satellite Circuits Using a Multi-Socket Extension to the File Transfer Protocol (FTP)

NASA Technical Reports Server (NTRS)

Allman, Mark; Ostermann, Shawn; Kruse, Hans

1996-01-01

In several experiments using NASA's Advanced Communications Technology Satellite (ACTS), investigators have reported disappointing throughput using the transmission control protocol/Internet protocol (TCP/IP) protocol suite over 1.536Mbit/sec (T1) satellite circuits. A detailed analysis of file transfer protocol (FTP) file transfers reveals that both the TCP window size and the TCP 'slow starter' algorithm contribute to the observed limits in throughput. In this paper we summarize the experimental and and theoretical analysis of the throughput limit imposed by TCP on the satellite circuit. We then discuss in detail the implementation of a multi-socket FTP, XFTP client and server. XFTP has been tested using the ACTS system. Finally, we discuss a preliminary set of tests on a link with non-zero bit error rates. XFTP shows promising performance under these conditions, suggesting the possibility that a multi-socket application may be less effected by bit errors than a single, large-window TCP connection.

An Efficient and Secure Arbitrary N-Party Quantum Key Agreement Protocol Using Bell States

NASA Astrophysics Data System (ADS)

Liu, Wen-Jie; Xu, Yong; Yang, Ching-Nung; Gao, Pei-Pei; Yu, Wen-Bin

2018-01-01

Two quantum key agreement protocols using Bell states and Bell measurement were recently proposed by Shukla et al. (Quantum Inf. Process. 13(11), 2391-2405, 2014). However, Zhu et al. pointed out that there are some security flaws and proposed an improved version (Quantum Inf. Process. 14(11), 4245-4254, 2015). In this study, we will show Zhu et al.'s improvement still exists some security problems, and its efficiency is not high enough. For solving these problems, we utilize four Pauli operations { I, Z, X, Y} to encode two bits instead of the original two operations { I, X} to encode one bit, and then propose an efficient and secure arbitrary N-party quantum key agreement protocol. In the protocol, the channel checking with decoy single photons is introduced to avoid the eavesdropper's flip attack, and a post-measurement mechanism is used to prevent against the collusion attack. The security analysis shows the present protocol can guarantee the correctness, security, privacy and fairness of quantum key agreement.

High-capacity quantum secure direct communication with two-photon six-qubit hyperentangled states

NASA Astrophysics Data System (ADS)

Wu, FangZhou; Yang, GuoJian; Wang, HaiBo; Xiong, Jun; Alzahrani, Faris; Hobiny, Aatef; Deng, FuGuo

2017-12-01

This study proposes the first high-capacity quantum secure direct communication (QSDC) with two-photon six-qubit hyper-entangled Bell states in two longitudinal momentum and polarization degrees of freedom (DOFs) of photon pairs, which can be generated using two 0.5 mm-thick type-I β barium borate crystal slabs aligned one behind the other and an eight-hole screen. The secret message can be independently encoded on the photon pairs with 64 unitary operations in all three DOFs. This protocol has a higher capacity than previous QSDC protocols because each photon pair can carry 6 bits of information, not just 2 or 4 bits. Our QSDC protocol decreases the influence of decoherence from environment noise by exploiting the decoy photons to check the security of the transmission of the first photon sequence. Compared with two-way QSDC protocols, our QSDC protocol is immune to an attack by an eavesdropper using Trojan horse attack strategies because it is a one-way quantum communication. The QSDC protocol has good applications in the future quantum communication because of all these features.

A Hierarchical Modulation Coherent Communication Scheme for Simultaneous Four-State Continuous-Variable Quantum Key Distribution and Classical Communication

NASA Astrophysics Data System (ADS)

Yang, Can; Ma, Cheng; Hu, Linxi; He, Guangqiang

2018-06-01

We present a hierarchical modulation coherent communication protocol, which simultaneously achieves classical optical communication and continuous-variable quantum key distribution. Our hierarchical modulation scheme consists of a quadrature phase-shifting keying modulation for classical communication and a four-state discrete modulation for continuous-variable quantum key distribution. The simulation results based on practical parameters show that it is feasible to transmit both quantum information and classical information on a single carrier. We obtained a secure key rate of 10^{-3} bits/pulse to 10^{-1} bits/pulse within 40 kilometers, and in the meantime the maximum bit error rate for classical information is about 10^{-7}. Because continuous-variable quantum key distribution protocol is compatible with standard telecommunication technology, we think our hierarchical modulation scheme can be used to upgrade the digital communication systems to extend system function in the future.

Secure multi-party quantum summation based on quantum Fourier transform

NASA Astrophysics Data System (ADS)

Yang, Hui-Yi; Ye, Tian-Yu

2018-06-01

In this paper, we propose a novel secure multi-party quantum summation protocol based on quantum Fourier transform, where the traveling particles are transmitted in a tree-type mode. The party who prepares the initial quantum states is assumed to be semi-honest, which means that she may misbehave on her own but will not conspire with anyone. The proposed protocol can resist both the outside attacks and the participant attacks. Especially, one party cannot obtain other parties' private integer strings; and it is secure for the colluding attack performed by at most n - 2 parties, where n is the number of parties. In addition, the proposed protocol calculates the addition of modulo d and implements the calculation of addition in a secret-by-secret way rather than a bit-by-bit way.

Security of counterfactual quantum cryptography

NASA Astrophysics Data System (ADS)

Yin, Zhen-Qiang; Li, Hong-Wei; Chen, Wei; Han, Zheng-Fu; Guo, Guang-Can

2010-10-01

Recently, a “counterfactual” quantum-key-distribution scheme was proposed by T.-G. Noh [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.103.230501 103, 230501 (2009)]. In this scheme, two legitimate distant peers may share secret keys even when the information carriers are not traveled in the quantum channel. We find that this protocol is equivalent to an entanglement distillation protocol. According to this equivalence, a strict security proof and the asymptotic key bit rate are both obtained when a perfect single-photon source is applied and a Trojan horse attack can be detected. We also find that the security of this scheme is strongly related to not only the bit error rate but also the yields of photons. And our security proof may shed light on the security of other two-way protocols.

Critique of a Hughes shuttle Ku-band data sampler/bit synchronizer

NASA Technical Reports Server (NTRS)

Holmes, J. K.

1980-01-01

An alternative bit synchronizer proposed for shuttle was analyzed in a noise-free environment by considering the basic operation of the loop via timing diagrams and by linearizing the bit synchronizer as an equivalent, continuous, phased-lock loop (PLL). The loop is composed of a high-frequency phase-frequency detector which is capable of detecting both phase and frequency errors and is used to track the clock, and a bit transition detector which attempts to track the transitions of the data bits. It was determined that the basic approach was a good design which, with proper implementation of the accumulator, up/down counter and logic should provide accurate mid-bit sampling with symmetric bits. However, when bit asymmetry occurs, the bit synchronizer can lock up with a large timing error, yet be quasi-stable (timing will not change unless the clock and bit sequence drift). This will result in incorrectly detecting some bits.

Experimental quantum key distribution with simulated ground-to-satellite photon losses and processing limitations

NASA Astrophysics Data System (ADS)

Bourgoin, Jean-Philippe; Gigov, Nikolay; Higgins, Brendon L.; Yan, Zhizhong; Meyer-Scott, Evan; Khandani, Amir K.; Lütkenhaus, Norbert; Jennewein, Thomas

2015-11-01

Quantum key distribution (QKD) has the potential to improve communications security by offering cryptographic keys whose security relies on the fundamental properties of quantum physics. The use of a trusted quantum receiver on an orbiting satellite is the most practical near-term solution to the challenge of achieving long-distance (global-scale) QKD, currently limited to a few hundred kilometers on the ground. This scenario presents unique challenges, such as high photon losses and restricted classical data transmission and processing power due to the limitations of a typical satellite platform. Here we demonstrate the feasibility of such a system by implementing a QKD protocol, with optical transmission and full post-processing, in the high-loss regime using minimized computing hardware at the receiver. Employing weak coherent pulses with decoy states, we demonstrate the production of secure key bits at up to 56.5 dB of photon loss. We further illustrate the feasibility of a satellite uplink by generating a secure key while experimentally emulating the varying losses predicted for realistic low-Earth-orbit satellite passes at 600 km altitude. With a 76 MHz source and including finite-size analysis, we extract 3374 bits of a secure key from the best pass. We also illustrate the potential benefit of combining multiple passes together: while one suboptimal "upper-quartile" pass produces no finite-sized key with our source, the combination of three such passes allows us to extract 165 bits of a secure key. Alternatively, we find that by increasing the signal rate to 300 MHz it would be possible to extract 21 570 bits of a secure finite-sized key in just a single upper-quartile pass.

Pattern recognition of electronic bit-sequences using a semiconductor mode-locked laser and spatial light modulators

NASA Astrophysics Data System (ADS)

Bhooplapur, Sharad; Akbulut, Mehmetkan; Quinlan, Franklyn; Delfyett, Peter J.

2010-04-01

A novel scheme for recognition of electronic bit-sequences is demonstrated. Two electronic bit-sequences that are to be compared are each mapped to a unique code from a set of Walsh-Hadamard codes. The codes are then encoded in parallel on the spectral phase of the frequency comb lines from a frequency-stabilized mode-locked semiconductor laser. Phase encoding is achieved by using two independent spatial light modulators based on liquid crystal arrays. Encoded pulses are compared using interferometric pulse detection and differential balanced photodetection. Orthogonal codes eight bits long are compared, and matched codes are successfully distinguished from mismatched codes with very low error rates, of around 10-18. This technique has potential for high-speed, high accuracy recognition of bit-sequences, with applications in keyword searches and internet protocol packet routing.

The Effects of Cognitive Jamming on Wireless Sensor Networks Used for Geolocation

DTIC Science & Technology

2012-03-01

continuously sends out random bits to the channel without following any MAC-layer etiquette [31]. Normally, the underlying MAC protocol allows...23 UDP User Datagram Protocol . . . . . . . . . . . . . . . . . . . 30 MIMO Multiple Input Multiple Output . . . . . . . . . . . . . . . 70...information is packaged and distributed on the network layer, only the physical measurements are considered. This protocol is used to detect faulty nodes

An economic and feasible Quantum Sealed-bid Auction protocol

NASA Astrophysics Data System (ADS)

Zhang, Rui; Shi, Run-hua; Qin, Jia-qi; Peng, Zhen-wan

2018-02-01

We present an economic and feasible Quantum Sealed-bid Auction protocol using quantum secure direct communication based on single photons in both the polarization and the spatial-mode degrees of freedom, where each single photon can carry two bits of classical information. Compared with previous protocols, our protocol has higher efficiency. In addition, we propose a secure post-confirmation mechanism without quantum entanglement to guarantee the security and the fairness of the auction.

Three-step semiquantum secure direct communication protocol

NASA Astrophysics Data System (ADS)

Zou, XiangFu; Qiu, DaoWen

2014-09-01

Quantum secure direct communication is the direct communication of secret messages without need for establishing a shared secret key first. In the existing schemes, quantum secure direct communication is possible only when both parties are quantum. In this paper, we construct a three-step semiquantum secure direct communication (SQSDC) protocol based on single photon sources in which the sender Alice is classical. In a semiquantum protocol, a person is termed classical if he (she) can measure, prepare and send quantum states only with the fixed orthogonal quantum basis {|0>, |1>}. The security of the proposed SQSDC protocol is guaranteed by the complete robustness of semiquantum key distribution protocols and the unconditional security of classical one-time pad encryption. Therefore, the proposed SQSDC protocol is also completely robust. Complete robustness indicates that nonzero information acquired by an eavesdropper Eve on the secret message implies the nonzero probability that the legitimate participants can find errors on the bits tested by this protocol. In the proposed protocol, we suggest a method to check Eves disturbing in the doves returning phase such that Alice does not need to announce publicly any position or their coded bits value after the photons transmission is completed. Moreover, the proposed SQSDC protocol can be implemented with the existing techniques. Compared with many quantum secure direct communication protocols, the proposed SQSDC protocol has two merits: firstly the sender only needs classical capabilities; secondly to check Eves disturbing after the transmission of quantum states, no additional classical information is needed.

Study of Using Excess Stock to Reduce Naval Aviation Depot-Level Repairable Piece Part Backorders

DTIC Science & Technology

2016-12-01

Designator Code, may get involved to ensure timely receipt. When a high-priority (Issue Priority Group 1) requisition is backordered, a CAS...alternative source for acquiring bit-piece parts is Navy excess material. Excess material is inventory designated by Navy organizations as meeting...potential alternative source for acquiring bit-piece parts is Navy excess material. Excess material is inventory designated by Navy organizations as

A Security Proof of Measurement Device Independent Quantum Key Distribution: From the View of Information Theory

NASA Astrophysics Data System (ADS)

Li, Fang-Yi; Yin, Zhen-Qiang; Li, Hong-Wei; Chen, Wei; Wang, Shuang; Wen, Hao; Zhao, Yi-Bo; Han, Zheng-Fu

2014-07-01

Although some ideal quantum key distribution protocols have been proved to be secure, there have been some demonstrations that practical quantum key distribution implementations were hacked due to some real-life imperfections. Among these attacks, detector side channel attacks may be the most serious. Recently, a measurement device independent quantum key distribution protocol [Phys. Rev. Lett. 108 (2012) 130503] was proposed and all detector side channel attacks are removed in this scheme. Here a new security proof based on quantum information theory is given. The eavesdropper's information of the sifted key bits is bounded. Then with this bound, the final secure key bit rate can be obtained.

Quantum Bit Commitment and the Reality of the Quantum State

NASA Astrophysics Data System (ADS)

Srikanth, R.

2018-01-01

Quantum bit commitment is insecure in the standard non-relativistic quantum cryptographic framework, essentially because Alice can exploit quantum steering to defer making her commitment. Two assumptions in this framework are that: (a) Alice knows the ensembles of evidence E corresponding to either commitment; and (b) system E is quantum rather than classical. Here, we show how relaxing assumption (a) or (b) can render her malicious steering operation indeterminable or inexistent, respectively. Finally, we present a secure protocol that relaxes both assumptions in a quantum teleportation setting. Without appeal to an ontological framework, we argue that the protocol's security entails the reality of the quantum state, provided retrocausality is excluded.

FPGA implementation of bit controller in double-tick architecture

NASA Astrophysics Data System (ADS)

Kobylecki, Michał; Kania, Dariusz

2017-11-01

This paper presents a comparison of the two original architectures of programmable bit controllers built on FPGAs. Programmable Logic Controllers (which include, among other things programmable bit controllers) built on FPGAs provide a efficient alternative to the controllers based on microprocessors which are expensive and often too slow. The presented and compared methods allow for the efficient implementation of any bit control algorithm written in Ladder Diagram language into the programmable logic system in accordance with IEC61131-3. In both cases, we have compared the effect of the applied architecture on the performance of executing the same bit control program in relation to its own size.

Interactive MPEG-4 low-bit-rate speech/audio transmission over the Internet

NASA Astrophysics Data System (ADS)

Liu, Fang; Kim, JongWon; Kuo, C.-C. Jay

1999-11-01

The recently developed MPEG-4 technology enables the coding and transmission of natural and synthetic audio-visual data in the form of objects. In an effort to extend the object-based functionality of MPEG-4 to real-time Internet applications, architectural prototypes of multiplex layer and transport layer tailored for transmission of MPEG-4 data over IP are under debate among Internet Engineering Task Force (IETF), and MPEG-4 systems Ad Hoc group. In this paper, we present an architecture for interactive MPEG-4 speech/audio transmission system over the Internet. It utilities a framework of Real Time Streaming Protocol (RTSP) over Real-time Transport Protocol (RTP) to provide controlled, on-demand delivery of real time speech/audio data. Based on a client-server model, a couple of low bit-rate bit streams (real-time speech/audio, pre- encoded speech/audio) are multiplexed and transmitted via a single RTP channel to the receiver. The MPEG-4 Scene Description (SD) and Object Descriptor (OD) bit streams are securely sent through the RTSP control channel. Upon receiving, an initial MPEG-4 audio- visual scene is constructed after de-multiplexing, decoding of bit streams, and scene composition. A receiver is allowed to manipulate the initial audio-visual scene presentation locally, or interactively arrange scene changes by sending requests to the server. A server may also choose to update the client with new streams and list of contents for user selection.

One Step Quantum Key Distribution Based on EPR Entanglement.

PubMed

Li, Jian; Li, Na; Li, Lei-Lei; Wang, Tao

2016-06-30

A novel quantum key distribution protocol is presented, based on entanglement and dense coding and allowing asymptotically secure key distribution. Considering the storage time limit of quantum bits, a grouping quantum key distribution protocol is proposed, which overcomes the vulnerability of first protocol and improves the maneuverability. Moreover, a security analysis is given and a simple type of eavesdropper's attack would introduce at least an error rate of 46.875%. Compared with the "Ping-pong" protocol involving two steps, the proposed protocol does not need to store the qubit and only involves one step.

Mars Rover Step Toward Possible Resumption of Drilling

NASA Image and Video Library

2017-10-23

NASA's Curiosity Mars rover conducted a test on Oct. 17, 2017, as part of the rover team's development of a new way to use the rover's drill. This image from Curiosity's front Hazard Avoidance Camera (Hazcam) shows the drill's bit touching the ground during an assessment of measurements by a sensor on the rover's robotic arm. Curiosity used its drill to acquire sample material from Martian rocks 15 times from 2013 to 2016. In December 2016, the drill's feed mechanism stopped working reliably. During the test shown in this image, the rover touched the drill bit to the ground for the first time in 10 months. The image has been adjusted to brighten shaded areas so that the bit is more evident. The date was the 1,848th Martian day, or sol, of Curiosity's work on Mars In drill use prior to December 2016, two contact posts -- the stabilizers on either side of the bit -- were placed on the target rock while the bit was in a withdrawn position. Then the motorized feed mechanism within the drill extended the bit forward, and the bit's rotation and percussion actions penetrated the rock. A promising alternative now under development and testing -- called feed-extended drilling -- uses motion of the robotic arm to directly advance the extended bit into a rock. In this image, the bit is touching the ground but the stabilizers are not. In the Sol 1848 activity, Curiosity pressed the drill bit downward, and then applied smaller sideways forces while taking measurements with a force/torque sensor on the arm. The objective was to gain understanding about how readings from the sensor can be used during drilling to adjust for any sideways pressure that might risk the bit becoming stuck in a rock. While rover-team engineers are working on an alternative drilling method, the mission continues to examine sites on Mount Sharp, Mars, with other tools. https://photojournal.jpl.nasa.gov/catalog/PIA22063

Fully Integrated Passive UHF RFID Tag for Hash-Based Mutual Authentication Protocol.

PubMed

Mikami, Shugo; Watanabe, Dai; Li, Yang; Sakiyama, Kazuo

2015-01-01

Passive radio-frequency identification (RFID) tag has been used in many applications. While the RFID market is expected to grow, concerns about security and privacy of the RFID tag should be overcome for the future use. To overcome these issues, privacy-preserving authentication protocols based on cryptographic algorithms have been designed. However, to the best of our knowledge, evaluation of the whole tag, which includes an antenna, an analog front end, and a digital processing block, that runs authentication protocols has not been studied. In this paper, we present an implementation and evaluation of a fully integrated passive UHF RFID tag that runs a privacy-preserving mutual authentication protocol based on a hash function. We design a single chip including the analog front end and the digital processing block. We select a lightweight hash function supporting 80-bit security strength and a standard hash function supporting 128-bit security strength. We show that when the lightweight hash function is used, the tag completes the protocol with a reader-tag distance of 10 cm. Similarly, when the standard hash function is used, the tag completes the protocol with the distance of 8.5 cm. We discuss the impact of the peak power consumption of the tag on the distance of the tag due to the hash function.

Progress on Ultra-Dense Quantum Communication Using Integrated Photonic Architecture

DTIC Science & Technology

2013-01-01

entanglement based quantum key distribution . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.2 Extended dispersive-optics QKD (DO-QKD) protocol...2 2.3 Analysis of non-local correlations of entangled photon pairs for arbitrary dis- persion...Section 3). 2 Protocol Development 2.1 Achieving multiple secure bits per coincidence in time-energy entanglement based quantum key distribution High

100 km differential phase shift quantum key distribution experiment with low jitter up-conversion detectors

NASA Astrophysics Data System (ADS)

Diamanti, Eleni; Takesue, Hiroki; Langrock, Carsten; Fejer, M. M.; Yamamoto, Yoshihisa

2006-12-01

We present a quantum key distribution experiment in which keys that were secure against all individual eavesdropping attacks allowed by quantum mechanics were distributed over 100 km of optical fiber. We implemented the differential phase shift quantum key distribution protocol and used low timing jitter 1.55 µm single-photon detectors based on frequency up-conversion in periodically poled lithium niobate waveguides and silicon avalanche photodiodes. Based on the security analysis of the protocol against general individual attacks, we generated secure keys at a practical rate of 166 bit/s over 100 km of fiber. The use of the low jitter detectors also increased the sifted key generation rate to 2 Mbit/s over 10 km of fiber.

A Survey of Rollback-Recovery Protocols in Message-Passing Systems

DTIC Science & Technology

1999-06-01

and M.A. Castillo. "Checkpointing through garbage collection." Technical report. Departamento de Ciencia de la Computation, Escuela de Ingenieria ...between consecutive checkpoints. It can be implemented by using the dirty-bit of the memory protection hardware or by emulating a dirty-bit in software [4...compare the program’s state with the previous checkpoint in software , and writing the difference in a new checkpoint [46]. The required storage and

Security proof of a three-state quantum-key-distribution protocol without rotational symmetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fung, C.-H.F.; Lo, H.-K.

2006-10-15

Standard security proofs of quantum-key-distribution (QKD) protocols often rely on symmetry arguments. In this paper, we prove the security of a three-state protocol that does not possess rotational symmetry. The three-state QKD protocol we consider involves three qubit states, where the first two states |0{sub z}> and |1{sub z}> can contribute to key generation, and the third state |+>=(|0{sub z}>+|1{sub z}>)/{radical}(2) is for channel estimation. This protocol has been proposed and implemented experimentally in some frequency-based QKD systems where the three states can be prepared easily. Thus, by founding on the security of this three-state protocol, we prove that thesemore » QKD schemes are, in fact, unconditionally secure against any attacks allowed by quantum mechanics. The main task in our proof is to upper bound the phase error rate of the qubits given the bit error rates observed. Unconditional security can then be proved not only for the ideal case of a single-photon source and perfect detectors, but also for the realistic case of a phase-randomized weak coherent light source and imperfect threshold detectors. Our result in the phase error rate upper bound is independent of the loss in the channel. Also, we compare the three-state protocol with the Bennett-Brassard 1984 (BB84) protocol. For the single-photon source case, our result proves that the BB84 protocol strictly tolerates a higher quantum bit error rate than the three-state protocol, while for the coherent-source case, the BB84 protocol achieves a higher key generation rate and secure distance than the three-state protocol when a decoy-state method is used.« less

Internet Protocol Handbook. Volume 4. The Domain Name System (DNS) handbook

DTIC Science & Technology

1989-08-01

Mockapetris [Page 1] 4-11 INTERNET PROTOCOL HA TDBOOK - Voue Four 1989 RFC 1034 Domain Concepts and Facilities November 1987 bandwidth consumed in distributing...Domain Names- Concepts and Facilities KFC 1034 RFC 1034 Domain Concepts and Facilities November 1’)87 - Queries contain a bit called recursion desired...during periodic sweeps to reclaim the memory consumed by old RRS. Mockapetris [Page 33] 4-43 INTERNET PROTOCOL HANDBOOK - Volume Four 1989 RFC 1034

New Rock-Drilling Method in 'Mars Yard' Test

NASA Image and Video Library

2017-10-23

This photo taken in the "Mars Yard" at NASA's Jet Propulsion Laboratory, Pasadena, California, on Aug. 1, 2017, shows a step in development of possible alternative techniques that NASA's Curiosity Mars rover might be able to use to resume drilling into rocks on Mars. In late 2016, after Curiosity's drill had collected sample material from 15 Martian rocks in four years, the drill's feed mechanism ceased working reliably. That motorized mechanism moved the bit forward or back with relation to stabilizer posts on either side of the bit. In normal drilling by Curiosity, the stabilizers were positioned on the target rock first, and then the feed mechanism extended the rotation-percussion bit into the rock. In the alternative technique seen here, called "feed-extended drilling," the test rover's stabilizers are not used to touch the rock. The bit is advanced into the rock by motion of the robotic arm rather than the drill's feed mechanism. https://photojournal.jpl.nasa.gov/catalog/PIA22062

JPEG 2000 Encoding with Perceptual Distortion Control

NASA Technical Reports Server (NTRS)

Watson, Andrew B.; Liu, Zhen; Karam, Lina J.

2008-01-01

An alternative approach has been devised for encoding image data in compliance with JPEG 2000, the most recent still-image data-compression standard of the Joint Photographic Experts Group. Heretofore, JPEG 2000 encoding has been implemented by several related schemes classified as rate-based distortion-minimization encoding. In each of these schemes, the end user specifies a desired bit rate and the encoding algorithm strives to attain that rate while minimizing a mean squared error (MSE). While rate-based distortion minimization is appropriate for transmitting data over a limited-bandwidth channel, it is not the best approach for applications in which the perceptual quality of reconstructed images is a major consideration. A better approach for such applications is the present alternative one, denoted perceptual distortion control, in which the encoding algorithm strives to compress data to the lowest bit rate that yields at least a specified level of perceptual image quality. Some additional background information on JPEG 2000 is prerequisite to a meaningful summary of JPEG encoding with perceptual distortion control. The JPEG 2000 encoding process includes two subprocesses known as tier-1 and tier-2 coding. In order to minimize the MSE for the desired bit rate, a rate-distortion- optimization subprocess is introduced between the tier-1 and tier-2 subprocesses. In tier-1 coding, each coding block is independently bit-plane coded from the most-significant-bit (MSB) plane to the least-significant-bit (LSB) plane, using three coding passes (except for the MSB plane, which is coded using only one "clean up" coding pass). For M bit planes, this subprocess involves a total number of (3M - 2) coding passes. An embedded bit stream is then generated for each coding block. Information on the reduction in distortion and the increase in the bit rate associated with each coding pass is collected. This information is then used in a rate-control procedure to determine the contribution of each coding block to the output compressed bit stream.

Finite-key analysis for the 1-decoy state QKD protocol

NASA Astrophysics Data System (ADS)

Rusca, Davide; Boaron, Alberto; Grünenfelder, Fadri; Martin, Anthony; Zbinden, Hugo

2018-04-01

It has been shown that in the asymptotic case of infinite-key length, the 2-decoy state Quantum Key Distribution (QKD) protocol outperforms the 1-decoy state protocol. Here, we present a finite-key analysis of the 1-decoy method. Interestingly, we find that for practical block sizes of up to 108 bits, the 1-decoy protocol achieves for almost all experimental settings higher secret key rates than the 2-decoy protocol. Since using only one decoy is also easier to implement, we conclude that it is the best choice for QKD, in most common practical scenarios.

One Step Quantum Key Distribution Based on EPR Entanglement

PubMed Central

Li, Jian; Li, Na; Li, Lei-Lei; Wang, Tao

2016-01-01

A novel quantum key distribution protocol is presented, based on entanglement and dense coding and allowing asymptotically secure key distribution. Considering the storage time limit of quantum bits, a grouping quantum key distribution protocol is proposed, which overcomes the vulnerability of first protocol and improves the maneuverability. Moreover, a security analysis is given and a simple type of eavesdropper’s attack would introduce at least an error rate of 46.875%. Compared with the “Ping-pong” protocol involving two steps, the proposed protocol does not need to store the qubit and only involves one step. PMID:27357865

Comment on: Supervisory Asymmetric Deterministic Secure Quantum Communication

NASA Astrophysics Data System (ADS)

Kao, Shih-Hung; Tsai, Chia-Wei; Hwang, Tzonelih

2012-12-01

In 2010, Xiu et al. (Optics Communications 284:2065-2069, 2011) proposed several applications based on a new secure four-site distribution scheme using χ-type entangled states. This paper points out that one of these applications, namely, supervisory asymmetric deterministic secure quantum communication, is subject to an information leakage problem, in which the receiver can extract two bits of a three-bit secret message without the supervisor's permission. An enhanced protocol is proposed to resolve this problem.

Method and apparatus for communicating computer data from one point to another over a communications medium

DOEpatents

Arneson, Michael R [Chippewa Falls, WI; Bowman, Terrance L [Sumner, WA; Cornett, Frank N [Chippewa Falls, WI; DeRyckere, John F [Eau Claire, WI; Hillert, Brian T [Chippewa Falls, WI; Jenkins, Philip N [Eau Claire, WI; Ma, Nan [Chippewa Falls, WI; Placek, Joseph M [Chippewa Falls, WI; Ruesch, Rodney [Eau Claire, WI; Thorson, Gregory M [Altoona, WI

2007-07-24

The present invention is directed toward a communications channel comprising a link level protocol, a driver, a receiver, and a canceller/equalizer. The link level protocol provides logic for DC-free signal encoding and recovery as well as supporting many features including CRC error detection and message resend to accommodate infrequent bit errors across the medium. The canceller/equalizer provides equalization for destabilized data signals and also provides simultaneous bi-directional data transfer. The receiver provides bit deskewing by removing synchronization error, or skewing, between data signals. The driver provides impedance controlling by monitoring the characteristics of the communications medium, like voltage or temperature, and providing a matching output impedance in the signal driver so that fewer distortions occur while the data travels across the communications medium.

The 40 Gbps cascaded bit-interleaving PON

NASA Astrophysics Data System (ADS)

Vyncke, A.; Torfs, G.; Van Praet, C.; Verbeke, M.; Duque, A.; Suvakovic, D.; Chow, H. K.; Yin, X.

2015-12-01

In this paper, a 40 Gbps cascaded bit-interleaving passive optical network (CBI-PON) is proposed to achieve power reduction in the network. The massive number of devices in the access network makes that power consumption reduction in this part of the network has a major impact on the total network power consumption. Starting from the proven BiPON technology, an extension to this concept is proposed to introduce multiple levels of bit-interleaving. The paper discusses the CBI protocol in detail, as well as an ASIC implementation of the required custom CBI Repeater and End-ONT. From the measurements of this first 40 Gbps ASIC prototype, power consumption reduction estimates are presented.

Fully Integrated Passive UHF RFID Tag for Hash-Based Mutual Authentication Protocol

PubMed Central

Mikami, Shugo; Watanabe, Dai; Li, Yang; Sakiyama, Kazuo

2015-01-01

Passive radio-frequency identification (RFID) tag has been used in many applications. While the RFID market is expected to grow, concerns about security and privacy of the RFID tag should be overcome for the future use. To overcome these issues, privacy-preserving authentication protocols based on cryptographic algorithms have been designed. However, to the best of our knowledge, evaluation of the whole tag, which includes an antenna, an analog front end, and a digital processing block, that runs authentication protocols has not been studied. In this paper, we present an implementation and evaluation of a fully integrated passive UHF RFID tag that runs a privacy-preserving mutual authentication protocol based on a hash function. We design a single chip including the analog front end and the digital processing block. We select a lightweight hash function supporting 80-bit security strength and a standard hash function supporting 128-bit security strength. We show that when the lightweight hash function is used, the tag completes the protocol with a reader-tag distance of 10 cm. Similarly, when the standard hash function is used, the tag completes the protocol with the distance of 8.5 cm. We discuss the impact of the peak power consumption of the tag on the distance of the tag due to the hash function. PMID:26491714

Microdot - A Four-Bit Microcontroller Designed for Distributed Low-End Computing in Satellites

NASA Astrophysics Data System (ADS)

2002-03-01

Many satellites are an integrated collection of sensors and actuators that require dedicated real-time control. For single processor systems, additional sensors require an increase in computing power and speed to provide the multi-tasking capability needed to service each sensor. Faster processors cost more and consume more power, which taxes a satellite's power resources and may lead to shorter satellite lifetimes. An alternative design approach is a distributed network of small and low power microcontrollers designed for space that handle the computing requirements of each individual sensor and actuator. The design of microdot, a four-bit microcontroller for distributed low-end computing, is presented. The design is based on previous research completed at the Space Electronics Branch, Air Force Research Laboratory (AFRL/VSSE) at Kirtland AFB, NM, and the Air Force Institute of Technology at Wright-Patterson AFB, OH. The Microdot has 29 instructions and a 1K x 4 instruction memory. The distributed computing architecture is based on the Philips Semiconductor I2C Serial Bus Protocol. A prototype was implemented and tested using an Altera Field Programmable Gate Array (FPGA). The prototype was operable to 9.1 MHz. The design was targeted for fabrication in a radiation-hardened-by-design gate-array cell library for the TSMC 0.35 micrometer CMOS process.

Fault-tolerant simple quantum-bit commitment unbreakable by individual attacks

NASA Astrophysics Data System (ADS)

Shimizu, Kaoru; Imoto, Nobuyuki

2002-03-01

This paper proposes a simple scheme for quantum-bit commitment that is secure against individual particle attacks, where a sender is unable to use quantum logical operations to manipulate multiparticle entanglement for performing quantum collective and coherent attacks. Our scheme employs a cryptographic quantum communication channel defined in a four-dimensional Hilbert space and can be implemented by using single-photon interference. For an ideal case of zero-loss and noiseless quantum channels, our basic scheme relies only on the physical features of quantum states. Moreover, as long as the bit-flip error rates are sufficiently small (less than a few percent), we can improve our scheme and make it fault tolerant by adopting simple error-correcting codes with a short length. Compared with the well-known Brassard-Crepeau-Jozsa-Langlois 1993 (BCJL93) protocol, our scheme is mathematically far simpler, more efficient in terms of transmitted photon number, and better tolerant of bit-flip errors.

Real-time echocardiogram transmission protocol based on regions and visualization modes.

PubMed

Cavero, Eva; Alesanco, Álvaro; García, José

2014-09-01

This paper proposes an Echocardiogram Transmission Protocol (ETP) for real-time end-to-end transmission of echocardiograms over IP networks. The ETP has been designed taking into account the echocardiogram characteristics of each visualized region, encoding each region according to its data type, visualization characteristics and diagnostic importance in order to improve the coding and thus the transmission efficiency. Furthermore, each region is sent separately and different error protection techniques can be used for each region. This leads to an efficient use of resources and provides greater protection for those regions with more clinical information. Synchronization is implemented for regions that change over time. The echocardiogram composition is different for each device. The protocol is valid for all echocardiogram devices thanks to the incorporation of configuration information which includes the composition of the echocardiogram. The efficiency of the ETP has been proved in terms of the number of bits sent with the proposed protocol. The codec and transmission rates used for the regions of interest have been set according to previous recommendations. Although the saving in the codified bits depends on the video composition, a coding gain higher than 7% with respect to without using ETP has been achieved.

Modulation and synchronization technique for MF-TDMA system

NASA Technical Reports Server (NTRS)

Faris, Faris; Inukai, Thomas; Sayegh, Soheil

1994-01-01

This report addresses modulation and synchronization techniques for a multi-frequency time division multiple access (MF-TDMA) system with onboard baseband processing. The types of synchronization techniques analyzed are asynchronous (conventional) TDMA, preambleless asynchronous TDMA, bit synchronous timing with a preamble, and preambleless bit synchronous timing. Among these alternatives, preambleless bit synchronous timing simplifies onboard multicarrier demultiplexer/demodulator designs (about 2:1 reduction in mass and power), requires smaller onboard buffers (10:1 to approximately 3:1 reduction in size), and provides better frame efficiency as well as lower onboard processing delay. Analysis and computer simulation illustrate that this technique can support a bit rate of up to 10 Mbit/s (or higher) with proper selection of design parameters. High bit rate transmission may require Doppler compensation and multiple phase error measurements. The recommended modulation technique for bit synchronous timing is coherent QPSK with differential encoding for the uplink and coherent QPSK for the downlink.

Proceedings of the Quantum Computation for Physical Modeling Workshop 2004. Held in North Falmouth, MA on 12-15 September 2004

DTIC Science & Technology

2005-10-01

late the difficulty of some basic 1-bit and n-bit quantum and classical operations in an simple unconstrained scenario. KEY WORDS: Time evolution... quantum circuit and design are presented for an optimized entangling probe attacking the BB84 Protocol of quantum key distribution (QKD) and yielding...unambiguous, at least some of the time. It follows that the BB84 (Bennett-Brassard 1984) proto- col of quantum key distribution has a vulnerability similar to

Counterfactuality of ‘counterfactual’ communication

NASA Astrophysics Data System (ADS)

Vaidman, L.

2015-11-01

The counterfactuality of the recently proposed protocols for direct quantum communication is analyzed. It is argued that the protocols can be counterfactual only for one value of the transmitted bit. The protocols achieve a reduced probability of detection of the particle in the transmission channel by increasing the number of paths in the channel. However, this probability is not lower than the probability of detecting a particle actually passing through such a multi-path channel, which was found to be surprisingly small. The relation between security and counterfactuality of the protocols is discussed. An analysis of counterfactuality of the protocols in the framework of the Bohmian interpretation is performed.

A History of the Improvement of Internet Protocols Over Satellites Using ACTS

NASA Technical Reports Server (NTRS)

Allman, Mark; Kruse, Hans; Ostermann, Shawn

2000-01-01

This paper outlines the main results of a number of ACTS experiments on the efficacy of using standard Internet protocols over long-delay satellite channels. These experiments have been jointly conducted by NASAs Glenn Research Center and Ohio University over the last six years. The focus of our investigations has been the impact of long-delay networks with non-zero bit-error rates on the performance of the suite of Internet protocols. In particular, we have focused on the most widely used transport protocol, the Transmission Control Protocol (TCP), as well as several application layer protocols. This paper presents our main results, as well as references to more verbose discussions of our experiments.

Efficacy trial of bioresonance in children with atopic dermatitis.

PubMed

Schöni, M H; Nikolaizik, W H; Schöni-Affolter, F

1997-03-01

Single case reports and uncontrolled studies claim significant improvements in patients with atopic diseases treated with bioresonance therapy, also called biophysical information therapy (BIT). To assess the efficacy of this alternative method of treatment, we performed a conventional double-blind parallel group study in children hospitalized for long-lasting atopic dermatitis. Over a period of 1.5 year, 32 children with atopic dermatitis, age range 1.5-16.8 years and hospitalized for 4-6 weeks at the Alpine Children's Hospital Davos, Switzerland, were randomized according to sex, age and severity of the skin disease to receive conventional inpatient therapy and either a putatively active or a sham (placebo) BIT treatment. Short- and long-term outcome within 1 year were assessed by skin symptom scores, sleep and itch scores, blood cell activation markers of allergy, and a questionnaire. Hospitalization and conventional therapy in a high altitude climate resulted in immediate and sustained amelioration of the disease state in both the BIT-treated and sham-treated groups. BIT had no significant additive measurable effect on the outcome variables determined in this study. The statement by protagonists of this alternative form of therapy that BIT can considerably influence or even cure atopic dermatitis was not confirmed using for the first time a conventional double-blind study design. Considering the high costs and false promises caused by the promotors of this kind of therapy, it is concluded that BIT has no place in the treatment of children with atopic dermatitis.

Alternation blindness in the representation of binary sequences.

PubMed

Yu, Ru Qi; Osherson, Daniel; Zhao, Jiaying

2018-03-01

Binary information is prevalent in the environment and contains 2 distinct outcomes. Binary sequences consist of a mixture of alternation and repetition. Understanding how people perceive such sequences would contribute to a general theory of information processing. In this study, we examined how people process alternation and repetition in binary sequences. Across 4 paradigms involving estimation, working memory, change detection, and visual search, we found that the number of alternations is underestimated compared with repetitions (Experiment 1). Moreover, recall for binary sequences deteriorates as the sequence alternates more (Experiment 2). Changes in bits are also harder to detect as the sequence alternates more (Experiment 3). Finally, visual targets superimposed on bits of a binary sequence take longer to process as alternation increases (Experiment 4). Overall, our results indicate that compared with repetition, alternation in a binary sequence is less salient in the sense of requiring more attention for successful encoding. The current study thus reveals the cognitive constraints in the representation of alternation and provides a new explanation for the overalternation bias in randomness perception. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Seaworthy Quantum Key Distribution Design and Validation (SEAKEY)

DTIC Science & Technology

2014-10-30

to single photon detection, at comparable detection efficiencies. On the other hand, error-correction codes are better developed for small-alphabet...protocol is several orders of magnitude better than the Shapiro protocol, which needs entangled states. The bits/mode performance achieved by our...putting together a software tool implemented in MATLAB , which talks to the MODTRAN database via an intermediate numerical dump of transmission data

Détection homodyne pour mémoires holographiques à stockage bit à bit

NASA Astrophysics Data System (ADS)

Maire, G.; Pauliat, G.; Roosen, G.

2006-10-01

Les mémoires holographiques à stockage bit à bit sont une alternative intéressante à l'approche holographique conventionnelle par pages de données du fait de leur architecture optique simplifiée. Nous proposons et validons ici une procédure de lecture adaptée à de telles mémoires et basée sur une détection homodyne de l'amplitude diffractée par les hologrammes. Ceci permet d'augmenter la quantité de signal utile détecté et s'avère donc prometteur pour accroître le taux de transfert de données de ces mémoires.

Secure polarization-independent subcarrier quantum key distribution in optical fiber channel using BB84 protocol with a strong reference.

PubMed

Gleim, A V; Egorov, V I; Nazarov, Yu V; Smirnov, S V; Chistyakov, V V; Bannik, O I; Anisimov, A A; Kynev, S M; Ivanova, A E; Collins, R J; Kozlov, S A; Buller, G S

2016-02-08

A quantum key distribution system based on the subcarrier wave modulation method has been demonstrated which employs the BB84 protocol with a strong reference to generate secure bits at a rate of 16.5 kbit/s with an error of 0.5% over an optical channel of 10 dB loss, and 18 bits/s with an error of 0.75% over 25 dB of channel loss. To the best of our knowledge, these results represent the highest channel loss reported for secure quantum key distribution using the subcarrier wave approach. A passive unidirectional scheme has been used to compensate for the polarization dependence of the phase modulators in the receiver module, which resulted in a high visibility of 98.8%. The system is thus fully insensitive to polarization fluctuations and robust to environmental changes, making the approach promising for use in optical telecommunication networks. Further improvements in secure key rate and transmission distance can be achieved by implementing the decoy states protocol or by optimizing the mean photon number used in line with experimental parameters.

Multiple speed expandable bit synchronizer

NASA Technical Reports Server (NTRS)

Bundinger, J. M.

1979-01-01

A multiple speed bit synchronizer was designed for installation in an inertial navigation system data decoder to extract non-return-to-zero level data and clock signal from biphase level data. The circuit automatically senses one of four pre-determined biphase data rates and synchronizes the proper clock rate to the data. Through a simple expansion of the basic design, synchronization of more than four binarily related data rates can be accomplished. The design provides an easily adaptable, low cost, low power alternative to external bit synchronizers with additional savings in size and weight.

Performance test of different 3.5 mm drill bits and consequences for orthopaedic surgery.

PubMed

Clement, Hans; Zopf, Christoph; Brandner, Markus; Tesch, Norbert P; Vallant, Rudolf; Puchwein, Paul

2015-12-01

Drilling of bones in orthopaedic and trauma surgery is a common procedure. There are yet no recommendations about which drill bits/coating should be preferred and when to change a used drill bit. In preliminary studies typical "drilling patterns" of surgeons concerning used spindle speed and feeding force were recorded. Different feeding forces were tested and abrasion was analysed using magnification and a scanning electron microscope (SEM). Acquired data were used for programming a friction stir welding machine (FSWM). Four drill bits (a default AISI 440A, a HSS, an AISI 440B and a Zirconium-oxide drill bit) were analysed for abrasive wear after 20/40/60 machine-guided and hand-driven drilled holes. Additionally different drill coatings [diamond-like carbon/grafitic (DLC), titanium nitride/carbide (Ti-N)] were tested. The mean applied feeding force by surgeons was 45 ± 15.6 Newton (N). HSS bits were still usable after 51 drill holes. Both coated AISI 440A bits showed considerable breakouts of the main cutting edge after 20 hand-driven drilled holes. The coated HSS bit showed very low abrasive wear. The non-coated AISI 440B bit had a similar durability to the HSS bits. The ZrO2 dental drill bit excelled its competitors (no considerable abrasive wear at >100 holes). If the default AISI 440A drill bit cannot be checked by 20-30× magnification after surgery, it should be replaced after 20 hand-driven drilled holes. Low price coated HSS bits could be a powerful alternative.

Comment on 'Quantum direct communication with authentication'

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Zhan-jun; Key Laboratory of Optoelectronic Information Acquisition and Manipulation of Ministry of Education of China, School of Physics and Material Science, Anhui University, Hefei 230039; Liu, Jun

2007-02-15

Two protocols of quantum direct communication with authentication [Phys. Rev. A 73, 042305 (2006)] were recently proposed by Lee, Lim, and Yang. In this paper we will show that in the two protocols the authenticator Trent should be prevented from knowing the secret message. The first protocol can be eavesdropped on by Trent using the intercept-measure-resend attack, while the second protocol can be eavesdropped on by Trent using a simple single-qubit measurement. To fix these leaks, we revise the original versions of the protocols by using the Pauli Z operation {sigma}{sub z} instead of the original bit-flip operation X. Asmore » a consequence, the attacks we present can be prevented and accordingly the protocol securities are improved.« less

Secure Multiparty AES

NASA Astrophysics Data System (ADS)

Damgård, Ivan; Keller, Marcel

We propose several variants of a secure multiparty computation protocol for AES encryption. The best variant requires 2200 + {{400}over{255}} expected elementary operations in expected 70 + {{20}over{255}} rounds to encrypt one 128-bit block with a 128-bit key. We implemented the variants using VIFF, a software framework for implementing secure multiparty computation (MPC). Tests with three players (passive security against at most one corrupted player) in a local network showed that one block can be encrypted in 2 seconds. We also argue that this result could be improved by an optimized implementation.

Open source software to control Bioflo bioreactors.

PubMed

Burdge, David A; Libourel, Igor G L

2014-01-01

Bioreactors are designed to support highly controlled environments for growth of tissues, cell cultures or microbial cultures. A variety of bioreactors are commercially available, often including sophisticated software to enhance the functionality of the bioreactor. However, experiments that the bioreactor hardware can support, but that were not envisioned during the software design cannot be performed without developing custom software. In addition, support for third party or custom designed auxiliary hardware is often sparse or absent. This work presents flexible open source freeware for the control of bioreactors of the Bioflo product family. The functionality of the software includes setpoint control, data logging, and protocol execution. Auxiliary hardware can be easily integrated and controlled through an integrated plugin interface without altering existing software. Simple experimental protocols can be entered as a CSV scripting file, and a Python-based protocol execution model is included for more demanding conditional experimental control. The software was designed to be a more flexible and free open source alternative to the commercially available solution. The source code and various auxiliary hardware plugins are publicly available for download from https://github.com/LibourelLab/BiofloSoftware. In addition to the source code, the software was compiled and packaged as a self-installing file for 32 and 64 bit windows operating systems. The compiled software will be able to control a Bioflo system, and will not require the installation of LabVIEW.

Open Source Software to Control Bioflo Bioreactors

PubMed Central

Burdge, David A.; Libourel, Igor G. L.

2014-01-01

Bioreactors are designed to support highly controlled environments for growth of tissues, cell cultures or microbial cultures. A variety of bioreactors are commercially available, often including sophisticated software to enhance the functionality of the bioreactor. However, experiments that the bioreactor hardware can support, but that were not envisioned during the software design cannot be performed without developing custom software. In addition, support for third party or custom designed auxiliary hardware is often sparse or absent. This work presents flexible open source freeware for the control of bioreactors of the Bioflo product family. The functionality of the software includes setpoint control, data logging, and protocol execution. Auxiliary hardware can be easily integrated and controlled through an integrated plugin interface without altering existing software. Simple experimental protocols can be entered as a CSV scripting file, and a Python-based protocol execution model is included for more demanding conditional experimental control. The software was designed to be a more flexible and free open source alternative to the commercially available solution. The source code and various auxiliary hardware plugins are publicly available for download from https://github.com/LibourelLab/BiofloSoftware. In addition to the source code, the software was compiled and packaged as a self-installing file for 32 and 64 bit windows operating systems. The compiled software will be able to control a Bioflo system, and will not require the installation of LabVIEW. PMID:24667828

A Weak Value Based QKD Protocol Robust Against Detector Attacks

NASA Astrophysics Data System (ADS)

Troupe, James

2015-03-01

We propose a variation of the BB84 quantum key distribution protocol that utilizes the properties of weak values to insure the validity of the quantum bit error rate estimates used to detect an eavesdropper. The protocol is shown theoretically to be secure against recently demonstrated attacks utilizing detector blinding and control and should also be robust against all detector based hacking. Importantly, the new protocol promises to achieve this additional security without negatively impacting the secure key generation rate as compared to that originally promised by the standard BB84 scheme. Implementation of the weak measurements needed by the protocol should be very feasible using standard quantum optical techniques.

Physical key-protected one-time pad

PubMed Central

Horstmeyer, Roarke; Judkewitz, Benjamin; Vellekoop, Ivo M.; Assawaworrarit, Sid; Yang, Changhuei

2013-01-01

We describe an encrypted communication principle that forms a secure link between two parties without electronically saving either of their keys. Instead, random cryptographic bits are kept safe within the unique mesoscopic randomness of two volumetric scattering materials. We demonstrate how a shared set of patterned optical probes can generate 10 gigabits of statistically verified randomness between a pair of unique 2 mm3 scattering objects. This shared randomness is used to facilitate information-theoretically secure communication following a modified one-time pad protocol. Benefits of volumetric physical storage over electronic memory include the inability to probe, duplicate or selectively reset any bits without fundamentally altering the entire key space. Our ability to securely couple the randomness contained within two unique physical objects can extend to strengthen hardware required by a variety of cryptographic protocols, which is currently a critically weak link in the security pipeline of our increasingly mobile communication culture. PMID:24345925

The Buried in Treasures Workshop: waitlist control trial of facilitated support groups for hoarding.

PubMed

Frost, Randy O; Ruby, Dylan; Shuer, Lee J

2012-11-01

Hoarding is a serious form of psychopathology that has been associated with significant health and safety concerns, as well as the source of social and economic burden (Tolin, Frost, Steketee, & Fitch, 2008; Tolin, Frost, Steketee, Gray, & Fitch, 2008). Recent developments in the treatment of hoarding have met with some success for both individual and group treatments. Nevertheless, the cost and limited accessibility of these treatments leave many hoarding sufferers without options for help. One alternative is support groups that require relatively few resources. Frost, Pekareva-Kochergina, and Maxner (2011) reported significant declines in hoarding symptoms following a non-professionally run 13-week support group (The Buried in Treasures [BIT] Workshop). The BIT Workshop is a highly structured and short term support group. The present study extended these findings by reporting on the results of a waitlist control trial of the BIT Workshop. Significant declines in all hoarding symptom measures were observed compared to a waitlist control. The treatment response rate for the BIT Workshop was similar to that obtained by previous individual and group treatment studies, despite its shorter length and lack of a trained therapist. The BIT Workshop may be an effective adjunct to cognitive behavior therapy for hoarding disorder, or an alternative when cognitive behavior therapy is inaccessible. Copyright © 2012 Elsevier Ltd. All rights reserved.

Design of MOEMS adjustable optical delay line to reduce link set-up time in a tera-bit/s optical interconnection network.

PubMed

Jing, Wencai; Zhang, Yimo; Zhou, Ge

2002-07-15

A new structure for bit synchronization in a tera-bit/s optical interconnection network has been designed using micro-electro-mechanical system (MEMS) technique. Link multiplexing has been adopted to reduce data packet communication latency. To eliminate link set-up time, adjustable optical delay lines (AODLs) have been adopted to shift the phases of the distributed optical clock signals for bit synchronization. By changing the optical path distance of the optical clock signal, the phase of the clock signal can be shifted at a very high resolution. A phase-shift resolution of 0.1 ps can be easily achieved with 30-microm alternation of the optical path length in vacuum.

An alternative design for a sparse distributed memory

NASA Technical Reports Server (NTRS)

Jaeckel, Louis A.

1989-01-01

A new design for a Sparse Distributed Memory, called the selected-coordinate design, is described. As in the original design, there are a large number of memory locations, each of which may be activated by many different addresses (binary vectors) in a very large address space. Each memory location is defined by specifying ten selected coordinates (bit positions in the address vectors) and a set of corresponding assigned values, consisting of one bit for each selected coordinate. A memory location is activated by an address if, for all ten of the locations's selected coordinates, the corresponding bits in the address vector match the respective assigned value bits, regardless of the other bits in the address vector. Some comparative memory capacity and signal-to-noise ratio estimates for the both the new and original designs are given. A few possible hardware embodiments of the new design are described.

The Level 0 Pixel Trigger system for the ALICE experiment

NASA Astrophysics Data System (ADS)

Aglieri Rinella, G.; Kluge, A.; Krivda, M.; ALICE Silicon Pixel Detector project

2007-01-01

The ALICE Silicon Pixel Detector contains 1200 readout chips. Fast-OR signals indicate the presence of at least one hit in the 8192 pixel matrix of each chip. The 1200 bits are transmitted every 100 ns on 120 data readout optical links using the G-Link protocol. The Pixel Trigger System extracts and processes them to deliver an input signal to the Level 0 trigger processor targeting a latency of 800 ns. The system is compact, modular and based on FPGA devices. The architecture allows the user to define and implement various trigger algorithms. The system uses advanced 12-channel parallel optical fiber modules operating at 1310 nm as optical receivers and 12 deserializer chips closely packed in small area receiver boards. Alternative solutions with multi-channel G-Link deserializers implemented directly in programmable hardware devices were investigated. The design of the system and the progress of the ALICE Pixel Trigger project are described in this paper.

Coexistence of WiFi and WiMAX systems based on PS-request protocols.

PubMed

Kim, Jongwoo; Park, Suwon; Rhee, Seung Hyong; Choi, Yong-Hoon; Chung, Young-uk; Hwang, Ho Young

2011-01-01

We introduce both the coexistence zone within the WiMAX frame structure and a PS-Request protocol for the coexistence of WiFi and WiMAX systems sharing a frequency band. Because we know that the PS-Request protocol has drawbacks, we propose a revised PS-Request protocol to improve the performance. Two PS-Request protocols are based on the time division operation (TDO) of WiFi system and WiMAX system to avoid the mutual interference, and use the vestigial power management (PwrMgt) bit within the Frame Control field of the frames transmitted by a WiFi AP. The performance of the revised PS-Request protocol is evaluated by computer simulation, and compared to those of the cases without a coexistence protocol and to the original PS-Request protocol.

A Tuned-RF Duty-Cycled Wake-Up Receiver with -90 dBm Sensitivity.

PubMed

Bdiri, Sadok; Derbel, Faouzi; Kanoun, Olfa

2017-12-29

A novel wake-up receiver for wireless sensor networks is introduced. It operates with a modified medium access protocol (MAC), allowing low-energy consumption and practical latency. The ultra-low-power wake-up receiver operates with enhanced duty-cycled listening. The analysis of energy models of the duty-cycle-based communication is presented. All the WuRx blocks are studied to obey the duty-cycle operation. For a mean interval time for the data exchange cycle between a transmitter and a receiver over 1.7 s and a 64-bit wake-up packet detection latency of 32 ms, the average power consumption of the wake-up receiver (WuRx) reaches down to 3 μ W . It also features scalable addressing of more than 512 bit at a data rate of 128 k bit / s -1 . At a wake-up packet error rate of 10 - 2 , the detection sensitivity reaches a minimum of - 90 dBm . The combination of the MAC protocol and the WuRx eases the adoption of different kinds of wireless sensor networks. In low traffic communication, the WuRx dramatically saves more energy than that of a network that is implementing conventional duty-cycling. In this work, a prototype was realized to evaluate the intended performance.

Alternative Line Coding Scheme with Fixed Dimming for Visible Light Communication

NASA Astrophysics Data System (ADS)

Niaz, M. T.; Imdad, F.; Kim, H. S.

2017-01-01

An alternative line coding scheme called fixed-dimming on/off keying (FD-OOK) is proposed for visible-light communication (VLC). FD-OOK reduces the flickering caused by a VLC transmitter and can maintain a 50% dimming level. Simple encoder and decoder are proposed which generates codes where the number of bits representing one is same as the number of bits representing zero. By keeping the number of ones and zeros equal the change in the brightness of lighting may be minimized and kept constant at 50%, thereby reducing the flickering in VLC. The performance of FD-OOK is analysed with two parameters: the spectral efficiency and power requirement.

Comment on "Bit-string oblivious transfer based on quantum state computational distinguishability"

NASA Astrophysics Data System (ADS)

He, Guang Ping

2015-10-01

We show that in the protocol proposed in Phys. Rev. A 91, 042306 (2015), 10.1103/PhysRevA.91.042306, a dishonest sender can always ensure with certainty that the receiver fails to get the secret message. Thus the security requirement of oblivious transfer is not met. This security problem also makes the protocol unsuitable for serving as a building block for 1-out-of-2 oblivious transfer.

Fast, efficient error reconciliation for quantum cryptography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buttler, W.T.; Lamoreaux, S.K.; Torgerson, J.R.

2003-05-01

We describe an error-reconciliation protocol, which we call Winnow, based on the exchange of parity and Hamming's 'syndrome' for N-bit subunits of a large dataset. The Winnow protocol was developed in the context of quantum-key distribution and offers significant advantages and net higher efficiency compared to other widely used protocols within the quantum cryptography community. A detailed mathematical analysis of the Winnow protocol is presented in the context of practical implementations of quantum-key distribution; in particular, the information overhead required for secure implementation is one of the most important criteria in the evaluation of a particular error-reconciliation protocol. The increasemore » in efficiency for the Winnow protocol is largely due to the reduction in authenticated public communication required for its implementation.« less

Secure quantum communication using classical correlated channel

NASA Astrophysics Data System (ADS)

Costa, D.; de Almeida, N. G.; Villas-Boas, C. J.

2016-10-01

We propose a secure protocol to send quantum information from one part to another without a quantum channel. In our protocol, which resembles quantum teleportation, a sender (Alice) and a receiver (Bob) share classical correlated states instead of EPR ones, with Alice performing measurements in two different bases and then communicating her results to Bob through a classical channel. Our secure quantum communication protocol requires the same amount of classical bits as the standard quantum teleportation protocol. In our scheme, as in the usual quantum teleportation protocol, once the classical channel is established in a secure way, a spy (Eve) will never be able to recover the information of the unknown quantum state, even if she is aware of Alice's measurement results. Security, advantages, and limitations of our protocol are discussed and compared with the standard quantum teleportation protocol.

Coexistence of WiFi and WiMAX Systems Based on PS-Request Protocols†

PubMed Central

Kim, Jongwoo; Park, Suwon; Rhee, Seung Hyong; Choi, Yong-Hoon; Chung, Young-uk; Hwang, Ho Young

2011-01-01

We introduce both the coexistence zone within the WiMAX frame structure and a PS-Request protocol for the coexistence of WiFi and WiMAX systems sharing a frequency band. Because we know that the PS-Request protocol has drawbacks, we propose a revised PS-Request protocol to improve the performance. Two PS-Request protocols are based on the time division operation (TDO) of WiFi system and WiMAX system to avoid the mutual interference, and use the vestigial power management (PwrMgt) bit within the Frame Control field of the frames transmitted by a WiFi AP. The performance of the revised PS-Request protocol is evaluated by computer simulation, and compared to those of the cases without a coexistence protocol and to the original PS-Request protocol. PMID:22163721

Practical Quantum Private Database Queries Based on Passive Round-Robin Differential Phase-shift Quantum Key Distribution.

PubMed

Li, Jian; Yang, Yu-Guang; Chen, Xiu-Bo; Zhou, Yi-Hua; Shi, Wei-Min

2016-08-19

A novel quantum private database query protocol is proposed, based on passive round-robin differential phase-shift quantum key distribution. Compared with previous quantum private database query protocols, the present protocol has the following unique merits: (i) the user Alice can obtain one and only one key bit so that both the efficiency and security of the present protocol can be ensured, and (ii) it does not require to change the length difference of the two arms in a Mach-Zehnder interferometer and just chooses two pulses passively to interfere with so that it is much simpler and more practical. The present protocol is also proved to be secure in terms of the user security and database security.

Efficient quantum state transfer in an engineered chain of quantum bits

NASA Astrophysics Data System (ADS)

Sandberg, Martin; Knill, Emanuel; Kapit, Eliot; Vissers, Michael R.; Pappas, David P.

2016-03-01

We present a method of performing quantum state transfer in a chain of superconducting quantum bits. Our protocol is based on engineering the energy levels of the qubits in the chain and tuning them all simultaneously with an external flux bias. The system is designed to allow sequential adiabatic state transfers, resulting in on-demand quantum state transfer from one end of the chain to the other. Numerical simulations of the master equation using realistic parameters for capacitive nearest-neighbor coupling, energy relaxation, and dephasing show that fast, high-fidelity state transfer should be feasible using this method.

Coherent attack on oblivious transfer based on single-qubit rotations

NASA Astrophysics Data System (ADS)

He, Guang Ping

2018-04-01

Recently a bit-string quantum oblivious transfer (OT) protocol based on single-qubit rotations was proposed (Rodrigues et al 2017 J. Phys. A: Math. Theor. 50 205301) and proven secure against few-qubit measurements. However, it was left as an open question whether the protocol remains secure against general attacks. Here, we close the gap by showing that if the receiver Bob can perform collective measurements on all qubits, then he can learn Alice’s secret message with a probability close to one. Thus the protocol fails to meet the security criterion of OT.

Deterministic and efficient quantum cryptography based on Bell's theorem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen Zengbing; Pan Jianwei; Physikalisches Institut, Universitaet Heidelberg, Philosophenweg 12, 69120 Heidelberg

2006-05-15

We propose a double-entanglement-based quantum cryptography protocol that is both efficient and deterministic. The proposal uses photon pairs with entanglement both in polarization and in time degrees of freedom; each measurement in which both of the two communicating parties register a photon can establish one and only one perfect correlation, and thus deterministically create a key bit. Eavesdropping can be detected by violation of local realism. A variation of the protocol shows a higher security, similar to the six-state protocol, under individual attacks. Our scheme allows a robust implementation under the current technology.

Advanced Shipboard Control Systems

DTIC Science & Technology

2001-05-07

Nov 1989: 41-47. Carnivale, J. A. DD-21 Presentation. Jan 1999. Deitel H.M. and P. J. Deitel . C++ How To Program . Upper Saddle River...One distinct advantage to an OSI model is that each level of the network is clearly defined, allowing different users to understand how a specific...Pri) field that tells the layer how this message is to be sent. The L2Hdr is an 8 bit section of the Link Protocol Data Unit/MAC Protocol Data

Bit by Bit: The Darwinian Basis of Life

PubMed Central

Joyce, Gerald F.

2012-01-01

All known examples of life belong to the same biology, but there is increasing enthusiasm among astronomers, astrobiologists, and synthetic biologists that other forms of life may soon be discovered or synthesized. This enthusiasm should be tempered by the fact that the probability for life to originate is not known. As a guiding principle in parsing potential examples of alternative life, one should ask: How many heritable “bits” of information are involved, and where did they come from? A genetic system that contains more bits than the number that were required to initiate its operation might reasonably be considered a new form of life. PMID:22589698

Less haste, less waste: on recycling and its limits in strand displacement systems

PubMed Central

Condon, Anne; Hu, Alan J.; Maňuch, Ján; Thachuk, Chris

2012-01-01

We study the potential for molecule recycling in chemical reaction systems and their DNA strand displacement realizations. Recycling happens when a product of one reaction is a reactant in a later reaction. Recycling has the benefits of reducing consumption, or waste, of molecules and of avoiding fuel depletion. We present a binary counter that recycles molecules efficiently while incurring just a moderate slowdown compared with alternative counters that do not recycle strands. This counter is an n-bit binary reflecting Gray code counter that advances through 2n states. In the strand displacement realization of this counter, the waste—total number of nucleotides of the DNA strands consumed—is polynomial in n, the number of bits of the counter, while the waste of alternative counters grows exponentially in n. We also show that our n-bit counter fails to work correctly when many (Θ(n)) copies of the species that represent the bits of the counter are present initially. The proof applies more generally to show that in chemical reaction systems where all but one reactant of each reaction are catalysts, computations longer than a polynomial function of the size of the system are not possible when there are polynomially many copies of the system present. PMID:22649584

24-Hour Relativistic Bit Commitment.

PubMed

Verbanis, Ephanielle; Martin, Anthony; Houlmann, Raphaël; Boso, Gianluca; Bussières, Félix; Zbinden, Hugo

2016-09-30

Bit commitment is a fundamental cryptographic primitive in which a party wishes to commit a secret bit to another party. Perfect security between mistrustful parties is unfortunately impossible to achieve through the asynchronous exchange of classical and quantum messages. Perfect security can nonetheless be achieved if each party splits into two agents exchanging classical information at times and locations satisfying strict relativistic constraints. A relativistic multiround protocol to achieve this was previously proposed and used to implement a 2-millisecond commitment time. Much longer durations were initially thought to be insecure, but recent theoretical progress showed that this is not so. In this Letter, we report on the implementation of a 24-hour bit commitment solely based on timed high-speed optical communication and fast data processing, with all agents located within the city of Geneva. This duration is more than 6 orders of magnitude longer than before, and we argue that it could be extended to one year and allow much more flexibility on the locations of the agents. Our implementation offers a practical and viable solution for use in applications such as digital signatures, secure voting and honesty-preserving auctions.

Beating the classical limits of information transmission using a quantum decoder

NASA Astrophysics Data System (ADS)

Chapman, Robert J.; Karim, Akib; Huang, Zixin; Flammia, Steven T.; Tomamichel, Marco; Peruzzo, Alberto

2018-01-01

Encoding schemes and error-correcting codes are widely used in information technology to improve the reliability of data transmission over real-world communication channels. Quantum information protocols can further enhance the performance in data transmission by encoding a message in quantum states; however, most proposals to date have focused on the regime of a large number of uses of the noisy channel, which is unfeasible with current quantum technology. We experimentally demonstrate quantum enhanced communication over an amplitude damping noisy channel with only two uses of the channel per bit and a single entangling gate at the decoder. By simulating the channel using a photonic interferometric setup, we experimentally increase the reliability of transmitting a data bit by greater than 20 % for a certain damping range over classically sending the message twice. We show how our methodology can be extended to larger systems by simulating the transmission of a single bit with up to eight uses of the channel and a two-bit message with three uses of the channel, predicting a quantum enhancement in all cases.

Cryptography in the Bounded-Quantum-Storage Model

NASA Astrophysics Data System (ADS)

Schaffner, Christian

2007-09-01

This thesis initiates the study of cryptographic protocols in the bounded-quantum-storage model. On the practical side, simple protocols for Rabin Oblivious Transfer, 1-2 Oblivious Transfer and Bit Commitment are presented. No quantum memory is required for honest players, whereas the protocols can only be broken by an adversary controlling a large amount of quantum memory. The protocols are efficient, non-interactive and can be implemented with today's technology. On the theoretical side, new entropic uncertainty relations involving min-entropy are established and used to prove the security of protocols according to new strong security definitions. For instance, in the realistic setting of Quantum Key Distribution (QKD) against quantum-memory-bounded eavesdroppers, the uncertainty relation allows to prove the security of QKD protocols while tolerating considerably higher error rates compared to the standard model with unbounded adversaries.

In-memory interconnect protocol configuration registers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Kevin Y.; Roberts, David A.

Systems, apparatuses, and methods for moving the interconnect protocol configuration registers into the main memory space of a node. The region of memory used for storing the interconnect protocol configuration registers may also be made cacheable to reduce the latency of accesses to the interconnect protocol configuration registers. Interconnect protocol configuration registers which are used during a startup routine may be prefetched into the host's cache to make the startup routine more efficient. The interconnect protocol configuration registers for various interconnect protocols may include one or more of device capability tables, memory-side statistics (e.g., to support two-level memory data mappingmore » decisions), advanced memory and interconnect features such as repair resources and routing tables, prefetching hints, error correcting code (ECC) bits, lists of device capabilities, set and store base address, capability, device ID, status, configuration, capabilities, and other settings.« less

Unconditional security of a three state quantum key distribution protocol.

PubMed

Boileau, J-C; Tamaki, K; Batuwantudawe, J; Laflamme, R; Renes, J M

2005-02-04

Quantum key distribution (QKD) protocols are cryptographic techniques with security based only on the laws of quantum mechanics. Two prominent QKD schemes are the Bennett-Brassard 1984 and Bennett 1992 protocols that use four and two quantum states, respectively. In 2000, Phoenix et al. proposed a new family of three-state protocols that offers advantages over the previous schemes. Until now, an error rate threshold for security of the symmetric trine spherical code QKD protocol has been shown only for the trivial intercept-resend eavesdropping strategy. In this Letter, we prove the unconditional security of the trine spherical code QKD protocol, demonstrating its security up to a bit error rate of 9.81%. We also discuss how this proof applies to a version of the trine spherical code QKD protocol where the error rate is evaluated from the number of inconclusive events.

Scalable SCPPM Decoder

NASA Technical Reports Server (NTRS)

Quir, Kevin J.; Gin, Jonathan W.; Nguyen, Danh H.; Nguyen, Huy; Nakashima, Michael A.; Moision, Bruce E.

2012-01-01

A decoder was developed that decodes a serial concatenated pulse position modulation (SCPPM) encoded information sequence. The decoder takes as input a sequence of four bit log-likelihood ratios (LLR) for each PPM slot in a codeword via a XAUI 10-Gb/s quad optical fiber interface. If the decoder is unavailable, it passes the LLRs on to the next decoder via a XAUI 10-Gb/s quad optical fiber interface. Otherwise, it decodes the sequence and outputs information bits through a 1-GB/s Ethernet UDP/IP (User Datagram Protocol/Internet Protocol) interface. The throughput for a single decoder unit is 150-Mb/s at an average of four decoding iterations; by connecting a number of decoder units in series, a decoding rate equal to that of the aggregate rate is achieved. The unit is controlled through a 1-GB/s Ethernet UDP/IP interface. This ground station decoder was developed to demonstrate a deep space optical communication link capability, and is unique in the scalable design to achieve real-time SCPP decoding at the aggregate data rate.

Bit Grooming: statistically accurate precision-preserving quantization with compression, evaluated in the netCDF Operators (NCO, v4.4.8+)

NASA Astrophysics Data System (ADS)

Zender, Charles S.

2016-09-01

Geoscientific models and measurements generate false precision (scientifically meaningless data bits) that wastes storage space. False precision can mislead (by implying noise is signal) and be scientifically pointless, especially for measurements. By contrast, lossy compression can be both economical (save space) and heuristic (clarify data limitations) without compromising the scientific integrity of data. Data quantization can thus be appropriate regardless of whether space limitations are a concern. We introduce, implement, and characterize a new lossy compression scheme suitable for IEEE floating-point data. Our new Bit Grooming algorithm alternately shaves (to zero) and sets (to one) the least significant bits of consecutive values to preserve a desired precision. This is a symmetric, two-sided variant of an algorithm sometimes called Bit Shaving that quantizes values solely by zeroing bits. Our variation eliminates the artificial low bias produced by always zeroing bits, and makes Bit Grooming more suitable for arrays and multi-dimensional fields whose mean statistics are important. Bit Grooming relies on standard lossless compression to achieve the actual reduction in storage space, so we tested Bit Grooming by applying the DEFLATE compression algorithm to bit-groomed and full-precision climate data stored in netCDF3, netCDF4, HDF4, and HDF5 formats. Bit Grooming reduces the storage space required by initially uncompressed and compressed climate data by 25-80 and 5-65 %, respectively, for single-precision values (the most common case for climate data) quantized to retain 1-5 decimal digits of precision. The potential reduction is greater for double-precision datasets. When used aggressively (i.e., preserving only 1-2 digits), Bit Grooming produces storage reductions comparable to other quantization techniques such as Linear Packing. Unlike Linear Packing, whose guaranteed precision rapidly degrades within the relatively narrow dynamic range of values that it can compress, Bit Grooming guarantees the specified precision throughout the full floating-point range. Data quantization by Bit Grooming is irreversible (i.e., lossy) yet transparent, meaning that no extra processing is required by data users/readers. Hence Bit Grooming can easily reduce data storage volume without sacrificing scientific precision or imposing extra burdens on users.

Practical Quantum Private Database Queries Based on Passive Round-Robin Differential Phase-shift Quantum Key Distribution

PubMed Central

Li, Jian; Yang, Yu-Guang; Chen, Xiu-Bo; Zhou, Yi-Hua; Shi, Wei-Min

2016-01-01

A novel quantum private database query protocol is proposed, based on passive round-robin differential phase-shift quantum key distribution. Compared with previous quantum private database query protocols, the present protocol has the following unique merits: (i) the user Alice can obtain one and only one key bit so that both the efficiency and security of the present protocol can be ensured, and (ii) it does not require to change the length difference of the two arms in a Mach-Zehnder interferometer and just chooses two pulses passively to interfere with so that it is much simpler and more practical. The present protocol is also proved to be secure in terms of the user security and database security. PMID:27539654

Synchronization of random bit generators based on coupled chaotic lasers and application to cryptography.

PubMed

Kanter, Ido; Butkovski, Maria; Peleg, Yitzhak; Zigzag, Meital; Aviad, Yaara; Reidler, Igor; Rosenbluh, Michael; Kinzel, Wolfgang

2010-08-16

Random bit generators (RBGs) constitute an important tool in cryptography, stochastic simulations and secure communications. The later in particular has some difficult requirements: high generation rate of unpredictable bit strings and secure key-exchange protocols over public channels. Deterministic algorithms generate pseudo-random number sequences at high rates, however, their unpredictability is limited by the very nature of their deterministic origin. Recently, physical RBGs based on chaotic semiconductor lasers were shown to exceed Gbit/s rates. Whether secure synchronization of two high rate physical RBGs is possible remains an open question. Here we propose a method, whereby two fast RBGs based on mutually coupled chaotic lasers, are synchronized. Using information theoretic analysis we demonstrate security against a powerful computational eavesdropper, capable of noiseless amplification, where all parameters are publicly known. The method is also extended to secure synchronization of a small network of three RBGs.

Issues to be resolved in Torrents—Future Revolutionised File Sharing

NASA Astrophysics Data System (ADS)

Thanekar, Sachin Arun

2010-11-01

Torrenting is a highly popular peer to peer file sharing activity that allows participants to send and receive files from other computers. As it is an advantageous technique as compare to traditional client server file sharing in terms of time, cost and speed, some drawbaks are also there. Content unavailability, lack of anonymity, leechers, cheaters and download speed consistency are the major problems to sort out. Efforts are needed to resolve these problems and to make this better application. Legal issues are also one of the measure factors of consideration. BitTorrent metafiles themselves do not store copyrighted data. Whether the publishers of BitTorrent metafiles violate copyrights by linking to copyrighted material is controversial. Various countries have taken legal action against websites that host BitTorrent trackers. Eg. Supernova.org, Torrentspy. Efforts are also needed to make such a useful protocol legal.

Entangled quantum key distribution over two free-space optical links.

PubMed

Erven, C; Couteau, C; Laflamme, R; Weihs, G

2008-10-13

We report on the first real-time implementation of a quantum key distribution (QKD) system using entangled photon pairs that are sent over two free-space optical telescope links. The entangled photon pairs are produced with a type-II spontaneous parametric down-conversion source placed in a central, potentially untrusted, location. The two free-space links cover a distance of 435 m and 1,325 m respectively, producing a total separation of 1,575 m. The system relies on passive polarization analysis units, GPS timing receivers for synchronization, and custom written software to perform the complete QKD protocol including error correction and privacy amplification. Over 6.5 hours during the night, we observed an average raw key generation rate of 565 bits/s, an average quantum bit error rate (QBER) of 4.92%, and an average secure key generation rate of 85 bits/s.

Quantifying the nonlocality of Greenberger-Horne-Zeilinger quantum correlations by a bounded communication simulation protocol.

PubMed

Branciard, Cyril; Gisin, Nicolas

2011-07-08

The simulation of quantum correlations with finite nonlocal resources, such as classical communication, gives a natural way to quantify their nonlocality. While multipartite nonlocal correlations appear to be useful resources, very little is known on how to simulate multipartite quantum correlations. We present a protocol that reproduces tripartite Greenberger-Horne-Zeilinger correlations with bounded communication: 3 bits in total turn out to be sufficient to simulate all equatorial Von Neumann measurements on the tripartite Greenberger-Horne-Zeilinger state.

ATM QoS Experiments Using TCP Applications: Performance of TCP/IP Over ATM in a Variety of Errored Links

NASA Technical Reports Server (NTRS)

Frantz, Brian D.; Ivancic, William D.

2001-01-01

Asynchronous Transfer Mode (ATM) Quality of Service (QoS) experiments using the Transmission Control Protocol/Internet Protocol (TCP/IP) were performed for various link delays. The link delay was set to emulate a Wide Area Network (WAN) and a Satellite Link. The purpose of these experiments was to evaluate the ATM QoS requirements for applications that utilize advance TCP/IP protocols implemented with large windows and Selective ACKnowledgements (SACK). The effects of cell error, cell loss, and random bit errors on throughput were reported. The detailed test plan and test results are presented herein.

Proposal for founding mistrustful quantum cryptography on coin tossing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kent, Adrian; Hewlett-Packard Laboratories, Filton Road, Stoke Gifford, Bristol BS34 8QZ,

2003-07-01

A significant branch of classical cryptography deals with the problems which arise when mistrustful parties need to generate, process, or exchange information. As Kilian showed a while ago, mistrustful classical cryptography can be founded on a single protocol, oblivious transfer, from which general secure multiparty computations can be built. The scope of mistrustful quantum cryptography is limited by no-go theorems, which rule out, inter alia, unconditionally secure quantum protocols for oblivious transfer or general secure two-party computations. These theorems apply even to protocols which take relativistic signaling constraints into account. The best that can be hoped for, in general, aremore » quantum protocols which are computationally secure against quantum attack. Here a method is described for building a classically certified bit commitment, and hence every other mistrustful cryptographic task, from a secure coin-tossing protocol. No security proof is attempted, but reasons are sketched why these protocols might resist quantum computational attack.« less

On Increasing Network Lifetime in Body Area Networks Using Global Routing with Energy Consumption Balancing

PubMed Central

Tsouri, Gill R.; Prieto, Alvaro; Argade, Nikhil

2012-01-01

Global routing protocols in wireless body area networks are considered. Global routing is augmented with a novel link cost function designed to balance energy consumption across the network. The result is a substantial increase in network lifetime at the expense of a marginal increase in energy per bit. Network maintenance requirements are reduced as well, since balancing energy consumption means all batteries need to be serviced at the same time and less frequently. The proposed routing protocol is evaluated using a hardware experimental setup comprising multiple nodes and an access point. The setup is used to assess network architectures, including an on-body access point and an off-body access point with varying number of antennas. Real-time experiments are conducted in indoor environments to assess performance gains. In addition, the setup is used to record channel attenuation data which are then processed in extensive computer simulations providing insight on the effect of protocol parameters on performance. Results demonstrate efficient balancing of energy consumption across all nodes, an average increase of up to 40% in network lifetime corresponding to a modest average increase of 0.4 dB in energy per bit, and a cutoff effect on required transmission power to achieve reliable connectivity. PMID:23201987

On increasing network lifetime in body area networks using global routing with energy consumption balancing.

PubMed

Tsouri, Gill R; Prieto, Alvaro; Argade, Nikhil

2012-09-26

Global routing protocols in wireless body area networks are considered. Global routing is augmented with a novel link cost function designed to balance energy consumption across the network. The result is a substantial increase in network lifetime at the expense of a marginal increase in energy per bit. Network maintenance requirements are reduced as well, since balancing energy consumption means all batteries need to be serviced at the same time and less frequently. The proposed routing protocol is evaluated using a hardware experimental setup comprising multiple nodes and an access point. The setup is used to assess network architectures, including an on-body access point and an off-body access point with varying number of antennas. Real-time experiments are conducted in indoor environments to assess performance gains. In addition, the setup is used to record channel attenuation data which are then processed in extensive computer simulations providing insight on the effect of protocol parameters on performance. Results demonstrate efficient balancing of energy consumption across all nodes, an average increase of up to 40% in network lifetime corresponding to a modest average increase of 0.4 dB in energy per bit, and a cutoff effect on required transmission power to achieve reliable connectivity.

47 CFR 11.31 - EAS protocol.

Code of Federal Regulations, 2013 CFR

2013-10-01

... End Of Message (EOM) Codes. (1) The Preamble and EAS Codes must use Audio Frequency Shift Keying at a rate of 520.83 bits per second to transmit the codes. Mark frequency is 2083.3 Hz and space frequency... Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Equipment Requirements § 11...

47 CFR 11.31 - EAS protocol.

Code of Federal Regulations, 2014 CFR

2014-10-01

... End Of Message (EOM) Codes. (1) The Preamble and EAS Codes must use Audio Frequency Shift Keying at a rate of 520.83 bits per second to transmit the codes. Mark frequency is 2083.3 Hz and space frequency... Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Equipment Requirements § 11...

47 CFR 11.31 - EAS protocol.

Code of Federal Regulations, 2010 CFR

2010-10-01

... End Of Message (EOM) Codes. (1) The Preamble and EAS Codes must use Audio Frequency Shift Keying at a rate of 520.83 bits per second to transmit the codes. Mark frequency is 2083.3 Hz and space frequency... Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Equipment Requirements § 11...

47 CFR 11.31 - EAS protocol.

Code of Federal Regulations, 2012 CFR

2012-10-01

... End Of Message (EOM) Codes. (1) The Preamble and EAS Codes must use Audio Frequency Shift Keying at a rate of 520.83 bits per second to transmit the codes. Mark frequency is 2083.3 Hz and space frequency... Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Equipment Requirements § 11...

47 CFR 11.31 - EAS protocol.

Code of Federal Regulations, 2011 CFR

2011-10-01

... End Of Message (EOM) Codes. (1) The Preamble and EAS Codes must use Audio Frequency Shift Keying at a rate of 520.83 bits per second to transmit the codes. Mark frequency is 2083.3 Hz and space frequency... Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Equipment Requirements § 11...

Enhancing Performance and Bit Rates in a Brain-Computer Interface System With Phase-to-Amplitude Cross-Frequency Coupling: Evidences From Traditional c-VEP, Fast c-VEP, and SSVEP Designs.

PubMed

Dimitriadis, Stavros I; Marimpis, Avraam D

2018-01-01

A brain-computer interface (BCI) is a channel of communication that transforms brain activity into specific commands for manipulating a personal computer or other home or electrical devices. In other words, a BCI is an alternative way of interacting with the environment by using brain activity instead of muscles and nerves. For that reason, BCI systems are of high clinical value for targeted populations suffering from neurological disorders. In this paper, we present a new processing approach in three publicly available BCI data sets: (a) a well-known multi-class ( N = 6) coded-modulated Visual Evoked potential (c-VEP)-based BCI system for able-bodied and disabled subjects; (b) a multi-class ( N = 32) c-VEP with slow and fast stimulus representation; and (c) a steady-state Visual Evoked potential (SSVEP) multi-class ( N = 5) flickering BCI system. Estimating cross-frequency coupling (CFC) and namely δ-θ [δ: (0.5-4 Hz), θ: (4-8 Hz)] phase-to-amplitude coupling (PAC) within sensor and across experimental time, we succeeded in achieving high classification accuracy and Information Transfer Rates (ITR) in the three data sets. Our approach outperformed the originally presented ITR on the three data sets. The bit rates obtained for both the disabled and able-bodied subjects reached the fastest reported level of 324 bits/min with the PAC estimator. Additionally, our approach outperformed alternative signal features such as the relative power (29.73 bits/min) and raw time series analysis (24.93 bits/min) and also the original reported bit rates of 10-25 bits/min . In the second data set, we succeeded in achieving an average ITR of 124.40 ± 11.68 for the slow 60 Hz and an average ITR of 233.99 ± 15.75 for the fast 120 Hz. In the third data set, we succeeded in achieving an average ITR of 106.44 ± 8.94. Current methodology outperforms any previous methodologies applied to each of the three free available BCI datasets.

Bit Grooming: Statistically accurate precision-preserving quantization with compression, evaluated in the netCDF operators (NCO, v4.4.8+)

DOE PAGES

Zender, Charles S.

2016-09-19

Geoscientific models and measurements generate false precision (scientifically meaningless data bits) that wastes storage space. False precision can mislead (by implying noise is signal) and be scientifically pointless, especially for measurements. By contrast, lossy compression can be both economical (save space) and heuristic (clarify data limitations) without compromising the scientific integrity of data. Data quantization can thus be appropriate regardless of whether space limitations are a concern. We introduce, implement, and characterize a new lossy compression scheme suitable for IEEE floating-point data. Our new Bit Grooming algorithm alternately shaves (to zero) and sets (to one) the least significant bits ofmore » consecutive values to preserve a desired precision. This is a symmetric, two-sided variant of an algorithm sometimes called Bit Shaving that quantizes values solely by zeroing bits. Our variation eliminates the artificial low bias produced by always zeroing bits, and makes Bit Grooming more suitable for arrays and multi-dimensional fields whose mean statistics are important. Bit Grooming relies on standard lossless compression to achieve the actual reduction in storage space, so we tested Bit Grooming by applying the DEFLATE compression algorithm to bit-groomed and full-precision climate data stored in netCDF3, netCDF4, HDF4, and HDF5 formats. Bit Grooming reduces the storage space required by initially uncompressed and compressed climate data by 25–80 and 5–65 %, respectively, for single-precision values (the most common case for climate data) quantized to retain 1–5 decimal digits of precision. The potential reduction is greater for double-precision datasets. When used aggressively (i.e., preserving only 1–2 digits), Bit Grooming produces storage reductions comparable to other quantization techniques such as Linear Packing. Unlike Linear Packing, whose guaranteed precision rapidly degrades within the relatively narrow dynamic range of values that it can compress, Bit Grooming guarantees the specified precision throughout the full floating-point range. Data quantization by Bit Grooming is irreversible (i.e., lossy) yet transparent, meaning that no extra processing is required by data users/readers. Hence Bit Grooming can easily reduce data storage volume without sacrificing scientific precision or imposing extra burdens on users.« less

An Improved Quantum Information Hiding Protocol Based on Entanglement Swapping of χ-type Quantum States

NASA Astrophysics Data System (ADS)

Xu, Shu-Jiang; Chen, Xiu-Bo; Wang, Lian-Hai; Ding, Qing-Yan; Zhang, Shu-Hui

2016-06-01

In 2011, Qu et al. proposed a quantum information hiding protocol based on the entanglement swapping of χ-type quantum states. Because a χ-type state can be described by the 4-particle cat states which have good symmetry, the possible output results of the entanglement swapping between a given χ-type state and all of the 16 χ-type states are divided into 8 groups instead of 16 groups of different results when the global phase is not considered. So it is difficult to read out the secret messages since each result occurs twice in each line (column) of the secret messages encoding rule for the original protocol. In fact, a 3-bit instead of a 4-bit secret message can be encoded by performing two unitary transformations on 2 particles of a χ-type quantum state in the original protocol. To overcome this defect, we propose an improved quantum information hiding protocol based on the general term formulas of the entanglement swapping among χ-type states. Supported by the National Natural Science Foundation of China under Grant Nos. 61572297, 61303199, 61272514, and 61373131, the Shandong Provincial Natural Science Foundation of China under Grant Nos. ZR2013FM025, ZR2013FQ001, ZR2014FM003, and ZY2015YL018, the Shandong Provincial Outstanding Research Award Fund for Young Scientists of China under Grant Nos. BS2015DX006 and BS2014DX007, the National Development Foundation for Cryptological Research, China under Grant No. MMJJ201401012, the Priority Academic Program Development of Jiangsu Higher Education Institutions and Jiangsu Collaborative Innovation Center on Atmospheric Environment and Equipment Technology Funds, and the Shandong Academy of Sciences Youth Fund Project, China under Grant Nos. 2015QN003 and 2013QN007

A security proof of the round-robin differential phase shift quantum key distribution protocol based on the signal disturbance

NASA Astrophysics Data System (ADS)

Sasaki, Toshihiko; Koashi, Masato

2017-06-01

The round-robin differential phase shift (RRDPS) quantum key distribution (QKD) protocol is a unique QKD protocol whose security has not been understood through an information-disturbance trade-off relation, and a sufficient amount of privacy amplification was given independently of signal disturbance. Here, we discuss the security of the RRDPS protocol in the asymptotic regime when a good estimate of the bit error rate is available as a measure of signal disturbance. The uniqueness of the RRDPS protocol shows up as a peculiar form of information-disturbance trade-off curve. When the length of a block of pulses used for encoding and the signal disturbance are both small, it provides a significantly better key rate than that from the original security proof. On the other hand, when the block length is large, the use of the signal disturbance makes little improvement in the key rate. Our analysis will bridge a gap between the RRDPS protocol and the conventional QKD protocols.

Two-dimensional distributed-phase-reference protocol for quantum key distribution

NASA Astrophysics Data System (ADS)

Bacco, Davide; Christensen, Jesper Bjerge; Castaneda, Mario A. Usuga; Ding, Yunhong; Forchhammer, Søren; Rottwitt, Karsten; Oxenløwe, Leif Katsuo

2016-12-01

Quantum key distribution (QKD) and quantum communication enable the secure exchange of information between remote parties. Currently, the distributed-phase-reference (DPR) protocols, which are based on weak coherent pulses, are among the most practical solutions for long-range QKD. During the last 10 years, long-distance fiber-based DPR systems have been successfully demonstrated, although fundamental obstacles such as intrinsic channel losses limit their performance. Here, we introduce the first two-dimensional DPR-QKD protocol in which information is encoded in the time and phase of weak coherent pulses. The ability of extracting two bits of information per detection event, enables a higher secret key rate in specific realistic network scenarios. Moreover, despite the use of more dimensions, the proposed protocol remains simple, practical, and fully integrable.

Two-dimensional distributed-phase-reference protocol for quantum key distribution.

PubMed

Bacco, Davide; Christensen, Jesper Bjerge; Castaneda, Mario A Usuga; Ding, Yunhong; Forchhammer, Søren; Rottwitt, Karsten; Oxenløwe, Leif Katsuo

2016-12-22

Quantum key distribution (QKD) and quantum communication enable the secure exchange of information between remote parties. Currently, the distributed-phase-reference (DPR) protocols, which are based on weak coherent pulses, are among the most practical solutions for long-range QKD. During the last 10 years, long-distance fiber-based DPR systems have been successfully demonstrated, although fundamental obstacles such as intrinsic channel losses limit their performance. Here, we introduce the first two-dimensional DPR-QKD protocol in which information is encoded in the time and phase of weak coherent pulses. The ability of extracting two bits of information per detection event, enables a higher secret key rate in specific realistic network scenarios. Moreover, despite the use of more dimensions, the proposed protocol remains simple, practical, and fully integrable.

Two-dimensional distributed-phase-reference protocol for quantum key distribution

PubMed Central

Bacco, Davide; Christensen, Jesper Bjerge; Castaneda, Mario A. Usuga; Ding, Yunhong; Forchhammer, Søren; Rottwitt, Karsten; Oxenløwe, Leif Katsuo

2016-01-01

Quantum key distribution (QKD) and quantum communication enable the secure exchange of information between remote parties. Currently, the distributed-phase-reference (DPR) protocols, which are based on weak coherent pulses, are among the most practical solutions for long-range QKD. During the last 10 years, long-distance fiber-based DPR systems have been successfully demonstrated, although fundamental obstacles such as intrinsic channel losses limit their performance. Here, we introduce the first two-dimensional DPR-QKD protocol in which information is encoded in the time and phase of weak coherent pulses. The ability of extracting two bits of information per detection event, enables a higher secret key rate in specific realistic network scenarios. Moreover, despite the use of more dimensions, the proposed protocol remains simple, practical, and fully integrable. PMID:28004821

Cryptographic robustness of a quantum cryptography system using phase-time coding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Molotkov, S. N.

2008-01-15

A cryptographic analysis is presented of a new quantum key distribution protocol using phase-time coding. An upper bound is obtained for the error rate that guarantees secure key distribution. It is shown that the maximum tolerable error rate for this protocol depends on the counting rate in the control time slot. When no counts are detected in the control time slot, the protocol guarantees secure key distribution if the bit error rate in the sifted key does not exceed 50%. This protocol partially discriminates between errors due to system defects (e.g., imbalance of a fiber-optic interferometer) and eavesdropping. In themore » absence of eavesdropping, the counts detected in the control time slot are not caused by interferometer imbalance, which reduces the requirements for interferometer stability.« less

Use of the DPP4BIT System for the Management of Hospital Medical Equipment.

PubMed

Tsoromokos, Dimitrios; Tsaloukidis, Nikolaos; Zarakovitis, Dimitrios; Lazakidou, Athina

2017-01-01

The Information and Communication Technologies (ICT) combined with the development of innovative skills within the broader health sector, can significantly improve and upgrade health care quality services. The proposed DDP4BIT system supports an alternative channel for digital information recording and equipment handling of Biomedical Technology Departments (BITs) of Health Care Units. This technology is ideal for all types of procedures based on handwritten forms that are commonly used in Health Care Units. The collection of useful statistics for analyzing and exporting data indicators is used in order to reduce ratios, such as operating time ratio, ideal operating time indicator, number of repetitive quality failures, total maintenance cost, etc. and supports decision-making.

Event-Triggered Distributed Average Consensus Over Directed Digital Networks With Limited Communication Bandwidth.

PubMed

Li, Huaqing; Chen, Guo; Huang, Tingwen; Dong, Zhaoyang; Zhu, Wei; Gao, Lan

2016-12-01

In this paper, we consider the event-triggered distributed average-consensus of discrete-time first-order multiagent systems with limited communication data rate and general directed network topology. In the framework of digital communication network, each agent has a real-valued state but can only exchange finite-bit binary symbolic data sequence with its neighborhood agents at each time step due to the digital communication channels with energy constraints. Novel event-triggered dynamic encoder and decoder for each agent are designed, based on which a distributed control algorithm is proposed. A scheme that selects the number of channel quantization level (number of bits) at each time step is developed, under which all the quantizers in the network are never saturated. The convergence rate of consensus is explicitly characterized, which is related to the scale of network, the maximum degree of nodes, the network structure, the scaling function, the quantization interval, the initial states of agents, the control gain and the event gain. It is also found that under the designed event-triggered protocol, by selecting suitable parameters, for any directed digital network containing a spanning tree, the distributed average consensus can be always achieved with an exponential convergence rate based on merely one bit information exchange between each pair of adjacent agents at each time step. Two simulation examples are provided to illustrate the feasibility of presented protocol and the correctness of the theoretical results.

Micro-mechanical resonators for dynamically reconfigurable reduced voltage logic gates

NASA Astrophysics Data System (ADS)

Chappanda, K. N.; Ilyas, S.; Younis, M. I.

2018-05-01

Due to the limitations of transistor-based logic devices such as their poor performance at elevated temperature, alternative computing methods are being actively investigated. In this work, we present electromechanical logic gates using electrostatically coupled in-plane micro-cantilever resonators operated at modest vacuum conditions of 5 Torr. Operating in the first resonant mode, we demonstrate 2-bit XOR, 2- and 3-bit AND, 2- and 3-bit NOR, and 1-bit NOT gates; all condensed in the same device. Through the designed electrostatic coupling, the required voltage for the logic gates is reduced by 80%, along with the reduction in the number of electrical interconnects and devices per logic operation (contrary to transistors). The device is dynamically reconfigurable between any logic gates in real time without the need for any change in the electrical interconnects and the drive circuit. By operating in the first two resonant vibration modes, we demonstrate mechanical logic gates consisting of two 2-bit AND and two 2-bit XOR gates. The device is tested at elevated temperatures and is shown to be functional as a logic gate up to 150 °C. Also, the device has high reliability with demonstrated lifetime greater than 5  ×  1012 oscillations.

Testing New Techniques for Mars Rover Rock-Drilling

NASA Image and Video Library

2017-10-23

In the summer and fall of 2017, the team operating NASA's Curiosity Mars rover conducted tests in the "Mars Yard" at NASA's Jet Propulsion Laboratory, Pasadena, California, to develop techniques that Curiosity might be able to use to resume drilling into rocks on Mars. JPL robotics engineer Vladimir Arutyunov, in this June 29, 2017, photo, checks the test rover's drill bit at its contact point with a rock. Note that the stabilizer post visible to the right of the bit is not in contact with the rock, unlike the positioning used and photographed by Curiosity when drilling into rocks on Mars in 2013 to 2016. In late 2016, after Curiosity's drill had collected sample material from 15 Martian rocks, the drill's feed mechanism ceased working reliably. That motorized mechanism moved the bit forward or back with relation to the stabilizer posts on either side of the bit. In normal drilling by Curiosity, the stabilizers were positioned on the target rock first, and then the feed mechanism extended the rotation-percussion bit into the rock. In the alternative technique seen here, called "feed-extended drilling," the test rover's stabilizers are not used to touch the rock. The bit is advanced into the rock by motion of the robotic arm rather than the drill's feed mechanism. https://photojournal.jpl.nasa.gov/catalog/PIA22061

Reducing weight precision of convolutional neural networks towards large-scale on-chip image recognition

NASA Astrophysics Data System (ADS)

Ji, Zhengping; Ovsiannikov, Ilia; Wang, Yibing; Shi, Lilong; Zhang, Qiang

2015-05-01

In this paper, we develop a server-client quantization scheme to reduce bit resolution of deep learning architecture, i.e., Convolutional Neural Networks, for image recognition tasks. Low bit resolution is an important factor in bringing the deep learning neural network into hardware implementation, which directly determines the cost and power consumption. We aim to reduce the bit resolution of the network without sacrificing its performance. To this end, we design a new quantization algorithm called supervised iterative quantization to reduce the bit resolution of learned network weights. In the training stage, the supervised iterative quantization is conducted via two steps on server - apply k-means based adaptive quantization on learned network weights and retrain the network based on quantized weights. These two steps are alternated until the convergence criterion is met. In this testing stage, the network configuration and low-bit weights are loaded to the client hardware device to recognize coming input in real time, where optimized but expensive quantization becomes infeasible. Considering this, we adopt a uniform quantization for the inputs and internal network responses (called feature maps) to maintain low on-chip expenses. The Convolutional Neural Network with reduced weight and input/response precision is demonstrated in recognizing two types of images: one is hand-written digit images and the other is real-life images in office scenarios. Both results show that the new network is able to achieve the performance of the neural network with full bit resolution, even though in the new network the bit resolution of both weight and input are significantly reduced, e.g., from 64 bits to 4-5 bits.

Secure anonymous mutual authentication for star two-tier wireless body area networks.

PubMed

Ibrahim, Maged Hamada; Kumari, Saru; Das, Ashok Kumar; Wazid, Mohammad; Odelu, Vanga

2016-10-01

Mutual authentication is a very important service that must be established between sensor nodes in wireless body area network (WBAN) to ensure the originality and integrity of the patient's data sent by sensors distributed on different parts of the body. However, mutual authentication service is not enough. An adversary can benefit from monitoring the traffic and knowing which sensor is in transmission of patient's data. Observing the traffic (even without disclosing the context) and knowing its origin, it can reveal to the adversary information about the patient's medical conditions. Therefore, anonymity of the communicating sensors is an important service as well. Few works have been conducted in the area of mutual authentication among sensor nodes in WBAN. However, none of them has considered anonymity among body sensor nodes. Up to our knowledge, our protocol is the first attempt to consider this service in a two-tier WBAN. We propose a new secure protocol to realize anonymous mutual authentication and confidential transmission for star two-tier WBAN topology. The proposed protocol uses simple cryptographic primitives. We prove the security of the proposed protocol using the widely-accepted Burrows-Abadi-Needham (BAN) logic, and also through rigorous informal security analysis. In addition, to demonstrate the practicality of our protocol, we evaluate it using NS-2 simulator. BAN logic and informal security analysis prove that our proposed protocol achieves the necessary security requirements and goals of an authentication service. The simulation results show the impact on the various network parameters, such as end-to-end delay and throughput. The nodes in the network require to store few hundred bits. Nodes require to perform very few hash invocations, which are computationally very efficient. The communication cost of the proposed protocol is few hundred bits in one round of communication. Due to the low computation cost, the energy consumed by the nodes is also low. Our proposed protocol is a lightweight anonymous mutually authentication protocol to mutually authenticate the sensor nodes with the controller node (hub) in a star two-tier WBAN topology. Results show that our protocol proves efficiency over previously proposed protocols and at the same time, achieves the necessary security requirements for a secure anonymous mutual authentication scheme. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Simpler Alternative to an Optimum FQPSK-B Viterbi Receiver

NASA Technical Reports Server (NTRS)

Lee, Dennis; Simon, Marvin; Yan, Tsun-Yee

2003-01-01

A reduced-complexity alternative to an optimum FQPSK-B Viterbi receiver has been invented. As described, the reduction in complexity is achieved at the cost of only a small reduction in power performance [performance expressed in terms of a bit-energy-to-noise-energy ratio (Eb/N0) for a given bit-error rate (BER)]. The term "FQPSK-B" denotes a baseband-filtered version of Feher quadrature-phase-shift keying, which is a patented, bandwidth-efficient phase-modulation scheme named after its inventor. Heretofore, commercial FQPSK-B receivers have performed symbol-by-symbol detection, in each case using a detection filter (either the proprietary FQPSK-B filter for better BER performance, or a simple integrate-and-dump filter with degraded performance) and a sample-and-hold circuit.

Design of Intelligent Cross-Layer Routing Protocols for Airborne Wireless Networks Under Dynamic Spectrum Access Paradigm

DTIC Science & Technology

2011-05-01

rate convolutional codes or the prioritized Rate - Compatible Punctured ...Quality of service RCPC Rate - compatible and punctured convolutional codes SNR Signal to noise ratio SSIM... Convolutional (RCPC) codes . The RCPC codes achieve UEP by puncturing off different amounts of coded bits of the parent code . The

Unconditional security of time-energy entanglement quantum key distribution using dual-basis interferometry.

PubMed

Zhang, Zheshen; Mower, Jacob; Englund, Dirk; Wong, Franco N C; Shapiro, Jeffrey H

2014-03-28

High-dimensional quantum key distribution (HDQKD) offers the possibility of high secure-key rate with high photon-information efficiency. We consider HDQKD based on the time-energy entanglement produced by spontaneous parametric down-conversion and show that it is secure against collective attacks. Its security rests upon visibility data-obtained from Franson and conjugate-Franson interferometers-that probe photon-pair frequency correlations and arrival-time correlations. From these measurements, an upper bound can be established on the eavesdropper's Holevo information by translating the Gaussian-state security analysis for continuous-variable quantum key distribution so that it applies to our protocol. We show that visibility data from just the Franson interferometer provides a weaker, but nonetheless useful, secure-key rate lower bound. To handle multiple-pair emissions, we incorporate the decoy-state approach into our protocol. Our results show that over a 200-km transmission distance in optical fiber, time-energy entanglement HDQKD could permit a 700-bit/sec secure-key rate and a photon information efficiency of 2 secure-key bits per photon coincidence in the key-generation phase using receivers with a 15% system efficiency.

Effect of quantum noise on deterministic joint remote state preparation of a qubit state via a GHZ channel

NASA Astrophysics Data System (ADS)

Wang, Ming-Ming; Qu, Zhi-Guo

2016-11-01

Quantum secure communication brings a new direction for information security. As an important component of quantum secure communication, deterministic joint remote state preparation (DJRSP) could securely transmit a quantum state with 100 % success probability. In this paper, we study how the efficiency of DJRSP is affected when qubits involved in the protocol are subjected to noise or decoherence. Taking a GHZ-based DJRSP scheme as an example, we study all types of noise usually encountered in real-world implementations of quantum communication protocols, i.e., the bit-flip, phase-flip (phase-damping), depolarizing and amplitude-damping noise. Our study shows that the fidelity of the output state depends on the phase factor, the amplitude factor and the noise parameter in the bit-flip noise, while the fidelity only depends on the amplitude factor and the noise parameter in the other three types of noise. And the receiver will get different output states depending on the first preparer's measurement result in the amplitude-damping noise. Our results will be helpful for improving quantum secure communication in real implementation.

Distributed reservation control protocols for random access broadcasting channels

NASA Technical Reports Server (NTRS)

Greene, E. P.; Ephremides, A.

1981-01-01

Attention is given to a communication network consisting of an arbitrary number of nodes which can communicate with each other via a time-division multiple access (TDMA) broadcast channel. The reported investigation is concerned with the development of efficient distributed multiple access protocols for traffic consisting primarily of single packet messages in a datagram mode of operation. The motivation for the design of the protocols came from the consideration of efficient multiple access utilization of moderate to high bandwidth (4-40 Mbit/s capacity) communication satellite channels used for the transmission of short (1000-10,000 bits) fixed length packets. Under these circumstances, the ratio of roundtrip propagation time to packet transmission time is between 100 to 10,000. It is shown how a TDMA channel can be adaptively shared by datagram traffic and constant bandwidth users such as in digital voice applications. The distributed reservation control protocols described are a hybrid between contention and reservation protocols.

Quantum and classical noise in practical quantum-cryptography systems based on polarization-entangled photons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castelletto, S.; Degiovanni, I.P.; Rastello, M.L.

2003-02-01

Quantum-cryptography key distribution (QCKD) experiments have been recently reported using polarization-entangled photons. However, in any practical realization, quantum systems suffer from either unwanted or induced interactions with the environment and the quantum measurement system, showing up as quantum and, ultimately, statistical noise. In this paper, we investigate how an ideal polarization entanglement in spontaneous parametric down-conversion (SPDC) suffers quantum noise in its practical implementation as a secure quantum system, yielding errors in the transmitted bit sequence. Since all SPDC-based QCKD schemes rely on the measurement of coincidence to assert the bit transmission between the two parties, we bundle up themore » overall quantum and statistical noise in an exhaustive model to calculate the accidental coincidences. This model predicts the quantum-bit error rate and the sifted key and allows comparisons between different security criteria of the hitherto proposed QCKD protocols, resulting in an objective assessment of performances and advantages of different systems.« less

Simplified management of ATM traffic

NASA Astrophysics Data System (ADS)

Luoma, Marko; Ilvesmaeki, Mika

1997-10-01

ATM has been under a thorough standardization process for more than ten years. Looking at it now, what have we achieved during this time period? Originally ATM was meant to be an easy and efficient protocol enabling varying services over a single network. What it is turning to be it `yet another ISDN'--network full of hopes and promises but too difficult to implement and expensive to market. The fact is that more and more `nice features' are implemented on the cost of overloading network with hard management procedures. Therefore we need to adopt a new approach. This approach keeps a strong reminder on `what is necessary.' This paper presents starting points for an alternative approach to the traffic management. We refer to this approach as `the minimum management principle.' Choosing of the suitable service classes for the ATM network is made difficult by the fact that the more services one implements the more management he needs. This is especially true for the variable bit rate connections that are usually treated based on the stochastic models. Stochastic model, at its best, can only reveal momentary characteristics in the traffic stream not the long range behavior of it. Our assumption is that ATM will move towards Internet in the sense that strict values for quality make little or no sense in the future. Therefore stochastic modeling of variable bit rate connections seems to be useless. Nevertheless we see that some traffic needs to have strict guarantees and that the only economic way of doing so is to use PCR allocation.

Controlled quantum secure communication protocol with single photons in both polarization and spatial-mode degrees of freedom

NASA Astrophysics Data System (ADS)

Wang, Lili; Ma, Wenping

2016-02-01

In this paper, we propose a new controlled quantum secure direct communication (CQSDC) protocol with single photons in both polarization and spatial-mode degrees of freedom. Based on the defined local collective unitary operations, the sender’s secret messages can be transmitted directly to the receiver through encoding secret messages on the particles. Only with the help of the third side, the receiver can reconstruct the secret messages. Each single photon in two degrees of freedom can carry two bits of information, so the cost of our protocol is less than others using entangled qubits. Moreover, the security of our QSDC network protocol is discussed comprehensively. It is shown that our new CQSDC protocol cannot only defend the outsider eavesdroppers’ several sorts of attacks but also the inside attacks. Besides, our protocol is feasible since the preparation and the measurement of single photon quantum states in both the polarization and the spatial-mode degrees of freedom are available with current quantum techniques.

Low-Energy Truly Random Number Generation with Superparamagnetic Tunnel Junctions for Unconventional Computing

NASA Astrophysics Data System (ADS)

Vodenicarevic, D.; Locatelli, N.; Mizrahi, A.; Friedman, J. S.; Vincent, A. F.; Romera, M.; Fukushima, A.; Yakushiji, K.; Kubota, H.; Yuasa, S.; Tiwari, S.; Grollier, J.; Querlioz, D.

2017-11-01

Low-energy random number generation is critical for many emerging computing schemes proposed to complement or replace von Neumann architectures. However, current random number generators are always associated with an energy cost that is prohibitive for these computing schemes. We introduce random number bit generation based on specific nanodevices: superparamagnetic tunnel junctions. We experimentally demonstrate high-quality random bit generation that represents an orders-of-magnitude improvement in energy efficiency over current solutions. We show that the random generation speed improves with nanodevice scaling, and we investigate the impact of temperature, magnetic field, and cross talk. Finally, we show how alternative computing schemes can be implemented using superparamagentic tunnel junctions as random number generators. These results open the way for fabricating efficient hardware computing devices leveraging stochasticity, and they highlight an alternative use for emerging nanodevices.

libvaxdata: VAX data format conversion routines

USGS Publications Warehouse

Baker, Lawrence M.

2005-01-01

libvaxdata provides a collection of routines for converting numeric data-integer and floating-point-to and from the formats used on a Digital Equipment Corporation1 (DEC) VAX 32-bit minicomputer (Brunner, 1991). Since the VAX numeric data formats are inherited from those used on a DEC PDP-11 16-bit minicomputer, these routines can be used to convert PDP-11 data as well. VAX numeric data formats are also the default data formats used on DEC Alpha 64-bit minicomputers running OpenVMS The libvaxdata routines are callable from Fortran or C. They require that the caller use two's-complement format for integer data and IEEE 754 format (ANSI/IEEE, 1985) for floating-point data. They also require that the 'natural' size of a C int type (integer) is 32 bits. That is the case for most modern 32-bit and 64-bit computer systems. Nevertheless, you may wish to consult the Fortran or C compiler documentation on your system to be sure. Some Fortran compilers support conversion of VAX numeric data on-the-fly when reading or writing unformatted files, either as a compiler option or a run-time I/O option. This feature may be easier to use than the libvaxdata routines. Consult the Fortran compiler documentation on your system to determine if this alternative is available to you. 1Later Compaq Computer Corporation, now Hewlett-Packard Company

2 GHz clock quantum key distribution over 260 km of standard telecom fiber.

PubMed

Wang, Shuang; Chen, Wei; Guo, Jun-Fu; Yin, Zhen-Qiang; Li, Hong-Wei; Zhou, Zheng; Guo, Guang-Can; Han, Zheng-Fu

2012-03-15

We report a demonstration of quantum key distribution (QKD) over a standard telecom fiber exceeding 50 dB in loss and 250 km in length. The differential phase shift QKD protocol was chosen and implemented with a 2 GHz system clock rate. By careful optimization of the 1 bit delayed Faraday-Michelson interferometer and the use of the superconducting single photon detector (SSPD), we achieved a quantum bit error rate below 2% when the fiber length was no more than 205 km, and of 3.45% for a 260 km fiber with 52.9 dB loss. We also improved the quantum efficiency of SSPD to obtain a high key rate for 50 km length.

Improving the capacity of the Boström-Felbinger protocol

NASA Astrophysics Data System (ADS)

Cai, Qing-Yu; Li, Bai-Wen

2004-05-01

We show that the capacity of the Boström-Felbinger (ping-pong) protocol [

The Behavior of TCP and Its Extensions in Space

NASA Technical Reports Server (NTRS)

Wang, Ruhai; Horan, Stephen

2001-01-01

The performance of Transmission Control Protocol (TCP) in space has been examined from the observations of simulation and experimental tests for several years at National Aeronautics and Space Administration (NASA), Department of Defense (DoD) and universities. At New Mexico State University (NMSU), we have been concentrating on studying the performance of two protocol suites: the file transfer protocol (ftp) running over Transmission Control Protocol/Internet Protocol (TCP/IP) stack and the file protocol (fp) running over the Space Communications Protocol Standards (SCPS)-Transport Protocol (TP) developed under the Consultative Committee for Space Data Systems (CCSDS) standards process. SCPS-TP is considered to be TCP's extensions for space communications. This dissertation experimentally studies the behavior of TCP and SCPS-TP by running the protocol suites over both the Space-to-Ground Link Simulator (SGLS) test-bed and realistic satellite link. The study concentrates on comparing protocol behavior by plotting the averaged file transfer times for different experimental configurations and analyzing them using Statistical Analysis System (SAS) based procedures. The effects of different link delays and various Bit-Error-Rates (BERS) on each protocol performance are also studied and linear regression models are built for experiments over SGLS test-bed to reflect the relationships between the file transfer time and various transmission conditions.

Towards communication-efficient quantum oblivious key distribution

NASA Astrophysics Data System (ADS)

Panduranga Rao, M. V.; Jakobi, M.

2013-01-01

Symmetrically private information retrieval, a fundamental problem in the field of secure multiparty computation, is defined as follows: A database D of N bits held by Bob is queried by a user Alice who is interested in the bit Db in such a way that (1) Alice learns Db and only Db and (2) Bob does not learn anything about Alice's choice b. While solutions to this problem in the classical domain rely largely on unproven computational complexity theoretic assumptions, it is also known that perfect solutions that guarantee both database and user privacy are impossible in the quantum domain. Jakobi [Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.83.022301 83, 022301 (2011)] proposed a protocol for oblivious transfer using well-known quantum key device (QKD) techniques to establish an oblivious key to solve this problem. Their solution provided a good degree of database and user privacy (using physical principles like the impossibility of perfectly distinguishing nonorthogonal quantum states and the impossibility of superluminal communication) while being loss-resistant and implementable with commercial QKD devices (due to the use of the Scarani-Acin-Ribordy-Gisin 2004 protocol). However, their quantum oblivious key distribution (QOKD) protocol requires a communication complexity of O(NlogN). Since modern databases can be extremely large, it is important to reduce this communication as much as possible. In this paper, we first suggest a modification of their protocol wherein the number of qubits that need to be exchanged is reduced to O(N). A subsequent generalization reduces the quantum communication complexity even further in such a way that only a few hundred qubits are needed to be transferred even for very large databases.

Twenty Seven Years of Quantum Cryptography!

NASA Astrophysics Data System (ADS)

Hughes, Richard

2011-03-01

One of the fundamental goals of cryptographic research is to minimize the assumptions underlying the protocols that enable secure communications between pairs or groups of users. In 1984, building on earlier research by Stephen Wiesner, Charles Bennett and Gilles Brassard showed how quantum physics could be harnessed to provide information-theoretic security for protocols such as the distribution of cryptographic keys, which enables two parties to secure their conventional communications. Bennett and Brassard and colleagues performed a proof-of-principle quantum key distribution (QKD) experiment with single-photon quantum state transmission over a 32-cm air path in 1991. This seminal experiment led other researchers to explore QKD in optical fibers and over line-of-sight outdoor atmospheric paths (``free-space''), resulting in dramatic increases in range, bit rate and security. These advances have been enabled by improvements in sources and single-photon detectors. Also in 1991 Artur Ekert showed how the security of QKD could be related to quantum entanglement. This insight led to a deeper understanding and proof of QKD security with practical sources and detectors in the presence of transmission loss and channel noise. Today, QKD has been implemented over ranges much greater than 100km in both fiber and free-space, multi-node network testbeds have been demonstrated, and satellite-based QKD is under study in several countries. ``Quantum hacking'' researchers have shown the importance of extending security considerations to the classical devices that produce and detect the photon quantum states. New quantum cryptographic protocols such as secure identification have been proposed, and others such as quantum secret splitting have been demonstrated. It is now possible to envision quantum cryptography providing a more secure alternative to present-day cryptographic methods for many secure communications functions. My talk will survey these remarkable developments.

Microelectromechanical reprogrammable logic device.

PubMed

Hafiz, M A A; Kosuru, L; Younis, M I

2016-03-29

In modern computing, the Boolean logic operations are set by interconnect schemes between the transistors. As the miniaturization in the component level to enhance the computational power is rapidly approaching physical limits, alternative computing methods are vigorously pursued. One of the desired aspects in the future computing approaches is the provision for hardware reconfigurability at run time to allow enhanced functionality. Here we demonstrate a reprogrammable logic device based on the electrothermal frequency modulation scheme of a single microelectromechanical resonator, capable of performing all the fundamental 2-bit logic functions as well as n-bit logic operations. Logic functions are performed by actively tuning the linear resonance frequency of the resonator operated at room temperature and under modest vacuum conditions, reprogrammable by the a.c.-driving frequency. The device is fabricated using complementary metal oxide semiconductor compatible mass fabrication process, suitable for on-chip integration, and promises an alternative electromechanical computing scheme.

Microelectromechanical reprogrammable logic device

PubMed Central

Hafiz, M. A. A.; Kosuru, L.; Younis, M. I.

2016-01-01

In modern computing, the Boolean logic operations are set by interconnect schemes between the transistors. As the miniaturization in the component level to enhance the computational power is rapidly approaching physical limits, alternative computing methods are vigorously pursued. One of the desired aspects in the future computing approaches is the provision for hardware reconfigurability at run time to allow enhanced functionality. Here we demonstrate a reprogrammable logic device based on the electrothermal frequency modulation scheme of a single microelectromechanical resonator, capable of performing all the fundamental 2-bit logic functions as well as n-bit logic operations. Logic functions are performed by actively tuning the linear resonance frequency of the resonator operated at room temperature and under modest vacuum conditions, reprogrammable by the a.c.-driving frequency. The device is fabricated using complementary metal oxide semiconductor compatible mass fabrication process, suitable for on-chip integration, and promises an alternative electromechanical computing scheme. PMID:27021295

A Robust and Efficient Quantum Private Comparison of Equality Based on the Entangled Swapping of GHZ-like State and χ + State

NASA Astrophysics Data System (ADS)

Xu, Ling; Zhao, Zhiwen

2017-08-01

A new quantum protocol with the assistance of a semi-honest third party (TP) is proposed, which allows the participants comparing the equality of their private information without disclosing them. Different from previous protocols, this protocol utilizes quantum key distribution against the collective-dephasing noise and the collective-rotation noise, which is more robust and abandons few samples, to transmit the classical information. In addition, this protocol utilizes the GHZ-like state and the χ + state to produce the entanglement swapping. And the Bell basis and the dual basis are used to measure the particle pair so that 3 bits of each participant's private information can be compared in each comparison time, which is more efficient and consumes fewer comparison times. Meanwhile, there is no need of unitary operation and hash function in this protocol. At the end, various kinds of outside attack and participant attack are discussed and analyzed to be invalid, so it can complete the comparison in security.

Patterned media towards Nano-bit magnetic recording: fabrication and challenges.

PubMed

Sbiaa, Rachid; Piramanayagam, Seidikkurippu N

2007-01-01

During the past decade, magnetic recording density of HDD has doubled almost every 18 months. To keep increasing the recording density, there is a need to make the small bits thermally stable. The most recent method using perpendicular recording media (PMR) will lose its fuel in a few years time and alternatives are sought. Patterned media, where the bits are magnetically separated from each other, offer the possibility to solve many issues encountered by PMR technology. However, implementation of patterned media would involve developing processing methods which offer high resolution (small bits), regular patterns, and high density. All these need to be achieved without sacrificing a high throughput and low cost. In this article, we review some of the ideas that have been proposed in this subject. However, the focus of the paper is on nano-imprint lithography (NIL) as it fulfills most of the needs of HDD as compared to conventional lithography using electron beam, EUV or X-Rays. The latest development of NIL and related technologies and their future prospects for patterned media are also discussed.

Dynamic quality of service model for improving performance of multimedia real-time transmission in industrial networks.

PubMed

Gopalakrishnan, Ravichandran C; Karunakaran, Manivannan

2014-01-01

Nowadays, quality of service (QoS) is very popular in various research areas like distributed systems, multimedia real-time applications and networking. The requirements of these systems are to satisfy reliability, uptime, security constraints and throughput as well as application specific requirements. The real-time multimedia applications are commonly distributed over the network and meet various time constraints across networks without creating any intervention over control flows. In particular, video compressors make variable bit-rate streams that mismatch the constant-bit-rate channels typically provided by classical real-time protocols, severely reducing the efficiency of network utilization. Thus, it is necessary to enlarge the communication bandwidth to transfer the compressed multimedia streams using Flexible Time Triggered- Enhanced Switched Ethernet (FTT-ESE) protocol. FTT-ESE provides automation to calculate the compression level and change the bandwidth of the stream. This paper focuses on low-latency multimedia transmission over Ethernet with dynamic quality-of-service (QoS) management. This proposed framework deals with a dynamic QoS for multimedia transmission over Ethernet with FTT-ESE protocol. This paper also presents distinct QoS metrics based both on the image quality and network features. Some experiments with recorded and live video streams show the advantages of the proposed framework. To validate the solution we have designed and implemented a simulator based on the Matlab/Simulink, which is a tool to evaluate different network architecture using Simulink blocks.

Periodically Relieving Ischial Sitting Load to Decrease the Risk of Pressure Ulcers

PubMed Central

Makhsous, Mohsen; Rowles, Diane M.; Rymer, William Z.; Bankard, James; Nam, Ellis K.; Chen, David; Lin, Fang

2010-01-01

Objective To investigate the relieving effect on interface pressure of an alternate sitting protocol involving a sitting posture that reduces ischial support. Design Repeated measures in 2 protocols on 3 groups of subjects. Setting Laboratory. Participants Twenty able-bodied persons, 20 persons with paraplegia, and 20 persons with tetraplegia. Interventions Two 1-hour protocols were used: alternate and normal plus pushup. In the alternate protocol, sitting posture was alternated every 10 minutes between normal (sitting upright with ischial support) and with partially removed ischial support (WO-BPS) postures; in the normal plus pushup protocol, sitting was in normal posture with pushups (lifting the subject off the seat) performed every 20 minutes. Main Outcome Measure Interface pressure on seat and backrest. Results In WO-BPS posture, the concentrated interface pressure observed around the ischia in normal posture was significantly repositioned to the thighs. By cyclically repositioning the interface pressure, the alternate protocol was superior to the normal plus pushup protocol in terms of a significantly lower average interface pressure over the buttocks. Conclusions A sitting protocol periodically reducing the ischial support helps lower the sitting load on the buttocks, especially the area close to ischial tuberosities. PMID:17601466

Multi-party quantum key agreement with five-qubit brown states

NASA Astrophysics Data System (ADS)

Cai, Tao; Jiang, Min; Cao, Gang

2018-05-01

In this paper, we propose a multi-party quantum key agreement protocol with five-qubit brown states and single-qubit measurements. Our multi-party protocol ensures each participant to contribute equally to the agreement key. Each party performs three single-qubit unitary operations on three qubits of each brown state. Finally, by measuring brown states and decoding the measurement results, all participants can negotiate a shared secret key without classical bits exchange between them. With the analysis of security, our protocol demonstrates that it can resist against both outsider and participant attacks. Compared with other schemes, it also possesses a higher information efficiency. In terms of physical operation, it requires single-qubit measurements only which weakens the hardware requirements of participant and has a better operating flexibility.

Security of counterfactual quantum cryptography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yin Zhenqiang; Li Hongwei; Chen Wei

2010-10-15

Recently, a 'counterfactual' quantum-key-distribution scheme was proposed by T.-G. Noh [Phys. Rev. Lett. 103, 230501 (2009)]. In this scheme, two legitimate distant peers may share secret keys even when the information carriers are not traveled in the quantum channel. We find that this protocol is equivalent to an entanglement distillation protocol. According to this equivalence, a strict security proof and the asymptotic key bit rate are both obtained when a perfect single-photon source is applied and a Trojan horse attack can be detected. We also find that the security of this scheme is strongly related to not only the bitmore » error rate but also the yields of photons. And our security proof may shed light on the security of other two-way protocols.« less

VCSEL-based fiber optic link for avionics: implementation and performance analyses

NASA Astrophysics Data System (ADS)

Shi, Jieqin; Zhang, Chunxi; Duan, Jingyuan; Wen, Huaitao

2006-11-01

A Gb/s fiber optic link with built-in test capability (BIT) basing on vertical-cavity surface-emitting laser (VCSEL) sources for military avionics bus for next generation has been presented in this paper. To accurately predict link performance, statistical methods and Bit Error Rate (BER) measurements have been examined. The results show that the 1Gb/s fiber optic link meets the BER requirement and values for link margin can reach up to 13dB. Analysis shows that the suggested photonic network may provide high performance and low cost interconnections alternative for future military avionics.

Leo Satellite Communication through a LEO Constellation using TCP/IP Over ATM

NASA Technical Reports Server (NTRS)

Foore, Lawrence R.; Konangi, Vijay K.; Wallett, Thomas M.

1999-01-01

The simulated performance characteristics for communication between a terrestrial client and a Low Earth Orbit (LEO) satellite server are presented. The client and server nodes consist of a Transmission Control Protocol /Internet Protocol (TCP/IP) over ATM configuration. The ATM cells from the client or the server are transmitted to a gateway, packaged with some header information and transferred to a commercial LEO satellite constellation. These cells are then routed through the constellation to a gateway on the globe that allows the client/server communication to take place. Unspecified Bit Rate (UBR) is specified as the quality of service (QoS). Various data rates are considered.

A microprocessor based on a two-dimensional semiconductor.

PubMed

Wachter, Stefan; Polyushkin, Dmitry K; Bethge, Ole; Mueller, Thomas

2017-04-11

The advent of microcomputers in the 1970s has dramatically changed our society. Since then, microprocessors have been made almost exclusively from silicon, but the ever-increasing demand for higher integration density and speed, lower power consumption and better integrability with everyday goods has prompted the search for alternatives. Germanium and III-V compound semiconductors are being considered promising candidates for future high-performance processor generations and chips based on thin-film plastic technology or carbon nanotubes could allow for embedding electronic intelligence into arbitrary objects for the Internet-of-Things. Here, we present a 1-bit implementation of a microprocessor using a two-dimensional semiconductor-molybdenum disulfide. The device can execute user-defined programs stored in an external memory, perform logical operations and communicate with its periphery. Our 1-bit design is readily scalable to multi-bit data. The device consists of 115 transistors and constitutes the most complex circuitry so far made from a two-dimensional material.

A microprocessor based on a two-dimensional semiconductor

NASA Astrophysics Data System (ADS)

Wachter, Stefan; Polyushkin, Dmitry K.; Bethge, Ole; Mueller, Thomas

2017-04-01

The advent of microcomputers in the 1970s has dramatically changed our society. Since then, microprocessors have been made almost exclusively from silicon, but the ever-increasing demand for higher integration density and speed, lower power consumption and better integrability with everyday goods has prompted the search for alternatives. Germanium and III-V compound semiconductors are being considered promising candidates for future high-performance processor generations and chips based on thin-film plastic technology or carbon nanotubes could allow for embedding electronic intelligence into arbitrary objects for the Internet-of-Things. Here, we present a 1-bit implementation of a microprocessor using a two-dimensional semiconductor--molybdenum disulfide. The device can execute user-defined programs stored in an external memory, perform logical operations and communicate with its periphery. Our 1-bit design is readily scalable to multi-bit data. The device consists of 115 transistors and constitutes the most complex circuitry so far made from a two-dimensional material.

Toward a Mobility-Driven Architecture for Multimodal Underwater Networking

DTIC Science & Technology

2017-02-01

applications. By equipping AUVs with short-range, high -bandwidth underwater wireless communications , which feature lower energy-per-bit cost than acoustic...protocols. They suffer from significant transmission path losses at high frequencies , long propagation delays, low and distance-dependent bandwidth, time...of data preprocessing, data compression, and either tethering to a surface buoy able to use radio frequency (RF) communications or using undersea

MOBS - A modular on-board switching system

NASA Astrophysics Data System (ADS)

Berner, W.; Grassmann, W.; Piontek, M.

The authors describe a multibeam satellite system that is designed for business services and for communications at a high bit rate. The repeater is regenerative with a modular onboard switching system. It acts not only as baseband switch but also as the central node of the network, performing network control and protocol evaluation. The hardware is based on a modular bus/memory architecture with associated processors.

Transfection using DEAE-dextran.

PubMed

Selden, R F

2001-05-01

Two protocols for DEAE-dextran transfection of cells are provided in this unit. The Basic Protocol describes a procedure used to transfect adherent cells and the first Alternate Protocol presents a method used to transfect suspension cells. If an increase in transfection efficiency is needed, cells can be treated with chloroquine as described in the second Alternate Protocol.

Quantum-locked key distribution at nearly the classical capacity rate.

PubMed

Lupo, Cosmo; Lloyd, Seth

2014-10-17

Quantum data locking is a protocol that allows for a small secret key to (un)lock an exponentially larger amount of information, hence yielding the strongest violation of the classical one-time pad encryption in the quantum setting. This violation mirrors a large gap existing between two security criteria for quantum cryptography quantified by two entropic quantities: the Holevo information and the accessible information. We show that the latter becomes a sensible security criterion if an upper bound on the coherence time of the eavesdropper's quantum memory is known. Under this condition, we introduce a protocol for secret key generation through a memoryless qudit channel. For channels with enough symmetry, such as the d-dimensional erasure and depolarizing channels, this protocol allows secret key generation at an asymptotic rate as high as the classical capacity minus one bit.

Quantum key distribution with prepare-and-measure Bell test

PubMed Central

Tan, Yong-gang

2016-01-01

The prepare-and-measure quantum key distribution (QKD) has the merits of fast speed, high key generation rate, and easy implementation. However, the detector side channel attacks greatly undermine the security of the key bits. The eavesdropper, Eve, exploits the flaws of the detectors to obtain illegal information without violating quantum principles. It means that she can intervene in the communication without being detected. A prepare-and-measure Bell test protocol will be proposed. By randomly carrying out Bell test at the side of the information receiver, Bob, Eve’s illegal information gain within the detector side channel attack can be well bounded. This protocol does not require any improvement on the detectors used in available prepare-and-measure QKD. Though we only illustrate its application in the BB84 protocol, it is applicable for any prepare-and-measure QKD. PMID:27733771

Improved LSB matching steganography with histogram characters reserved

NASA Astrophysics Data System (ADS)

Chen, Zhihong; Liu, Wenyao

2008-03-01

This letter bases on the researches of LSB (least significant bit, i.e. the last bit of a binary pixel value) matching steganographic method and the steganalytic method which aims at histograms of cover images, and proposes a modification to LSB matching. In the LSB matching, if the LSB of the next cover pixel matches the next bit of secret data, do nothing; otherwise, choose to add or subtract one from the cover pixel value at random. In our improved method, a steganographic information table is defined and records the changes which embedded secrete bits introduce in. Through the table, the next LSB which has the same pixel value will be judged to add or subtract one dynamically in order to ensure the histogram's change of cover image is minimized. Therefore, the modified method allows embedding the same payload as the LSB matching but with improved steganographic security and less vulnerability to attacks compared with LSB matching. The experimental results of the new method show that the histograms maintain their attributes, such as peak values and alternative trends, in an acceptable degree and have better performance than LSB matching in the respects of histogram distortion and resistance against existing steganalysis.

Examination of a Capabilities-based Prioritization Scheme for Service-Oriented Architecture Afloat

DTIC Science & Technology

2012-09-01

Oriented Architecture Afloat 5. FUNDING NUMBERS 6. AUTHOR(S) Matthew C. Horton 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS (ES) Naval...Postgraduate School Monterey, CA 93943–5000 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING /MONITORING AGENCY NAME(S) AND ADDRESS (ES) N/A...within the Internet Protocol Version 4 ( IPv4 ) header (Xiao & Ni, 1999). By manipulating three bits within this byte, applications may specify

Simple and high-speed polarization-based QKD

NASA Astrophysics Data System (ADS)

Grünenfelder, Fadri; Boaron, Alberto; Rusca, Davide; Martin, Anthony; Zbinden, Hugo

2018-01-01

We present a simplified BB84 protocol with only three quantum states and one decoy-state level. We implement this scheme using the polarization degree of freedom at telecom wavelength. Only one pulsed laser is used in order to reduce possible side-channel attacks. The repetition rate of 625 MHz and the achieved secret bit rate of 23 bps over 200 km of standard fiber are the actual state of the art.

A Tuned-RF Duty-Cycled Wake-Up Receiver with −90 dBm Sensitivity

PubMed Central

Derbel, Faouzi; Kanoun, Olfa

2017-01-01

A novel wake-up receiver for wireless sensor networks is introduced. It operates with a modified medium access protocol (MAC), allowing low-energy consumption and practical latency. The ultra-low-power wake-up receiver operates with enhanced duty-cycled listening. The analysis of energy models of the duty-cycle-based communication is presented. All the WuRx blocks are studied to obey the duty-cycle operation. For a mean interval time for the data exchange cycle between a transmitter and a receiver over 1.7 s and a 64-bit wake-up packet detection latency of 32 ms, the average power consumption of the wake-up receiver (WuRx) reaches down to 3 μW. It also features scalable addressing of more than 512 bit at a data rate of 128kbit/s−1. At a wake-up packet error rate of 10−2, the detection sensitivity reaches a minimum of −90 dBm. The combination of the MAC protocol and the WuRx eases the adoption of different kinds of wireless sensor networks. In low traffic communication, the WuRx dramatically saves more energy than that of a network that is implementing conventional duty-cycling. In this work, a prototype was realized to evaluate the intended performance. PMID:29286345

A large-alphabet three-party quantum key distribution protocol based on orbital and spin angular momenta hybrid entanglement

NASA Astrophysics Data System (ADS)

Lai, Hong; Luo, Mingxing; Zhang, Jun; Pieprzyk, Josef; Pan, Lei; Orgun, Mehmet A.

2018-07-01

The orthogonality of the orbital angular momentum (OAM) eigenstates enables a single photon carry an arbitrary number of bits. Moreover, additional degrees of freedom (DOFs) of OAM can span a high-dimensional Hilbert space, which could greatly increase information capacity and security. Moreover, the use of the spin angular momentum-OAM hybrid entangled state can increase Shannon dimensionality, because photons can be hybrid entangled in multiple DOFs. Based on these observations, we develop a hybrid entanglement quantum key distribution (QKD) protocol to achieve three-party quantum key distribution without classical message exchanges. In our proposed protocol, a communicating party uses a spatial light modulator (SLM) and a specific phase hologram to modulate photons' OAM state. Similarly, the other communicating parties use their SLMs and the fixed different phase holograms to modulate the OAM entangled photon pairs, producing the shared key among the parties Alice, Bob and Charlie without classical message exchanges. More importantly, when the same operation is repeated for every party, our protocol could be extended to a multiple-party QKD protocol.

Optical Fiber Transmission In A Picture Archiving And Communication System For Medical Applications

NASA Astrophysics Data System (ADS)

Aaron, Gilles; Bonnard, Rene

1984-03-01

In an hospital, the need for an electronic communication network is increasing along with the digitization of pictures. This local area network is intended to link some picture sources such as digital radiography, computed tomography, nuclear magnetic resonance, ultrasounds etc...with an archiving system. Interactive displays can be used in examination rooms, physicians offices and clinics. In such a system, three major requirements must be considered : bit-rate, cable length, and number of devices. - The bit-rate is very important because a maximum response time of a few seconds must be guaranteed for several mega-bit pictures. - The distance between nodes may be a few kilometers in some large hospitals. - The number of devices connected to the network is never greater than a few tens because picture sources and computers represent important hardware, and simple displays can be concentrated. All these conditions are fulfilled by optical fiber transmissions. Depending on the topology and the access protocol, two solutions are to be considered - Active ring - Active or passive star Finally Thomson-CSF developments of optical transmission devices for large networks of TV distribution bring us a technological support and a mass produc-tion which will cut down hardware costs.

Back-end and interface implementation of the STS-XYTER2 prototype ASIC for the CBM experiment

NASA Astrophysics Data System (ADS)

Kasinski, K.; Szczygiel, R.; Zabolotny, W.

2016-11-01

Each front-end readout ASIC for the High-Energy Physics experiments requires robust and effective hit data streaming and control mechanism. A new STS-XYTER2 full-size prototype chip for the Silicon Tracking System and Muon Chamber detectors in the Compressed Baryonic Matter experiment at Facility for Antiproton and Ion Research (FAIR, Germany) is a 128-channel time and amplitude measuring solution for silicon microstrip and gas detectors. It operates at 250 kHit/s/channel hit rate, each hit producing 27 bits of information (5-bit amplitude, 14-bit timestamp, position and diagnostics data). The chip back-end implements fast front-end channel read-out, timestamp-wise hit sorting, and data streaming via a scalable interface implementing the dedicated protocol (STS-HCTSP) for chip control and hit transfer with data bandwidth from 9.7 MHit/s up to 47 MHit/s. It also includes multiple options for link diagnostics, failure detection, and throttling features. The back-end is designed to operate with the data acquisition architecture based on the CERN GBTx transceivers. This paper presents the details of the back-end and interface design and its implementation in the UMC 180 nm CMOS process.

Cryptographie quantique à variables continues

NASA Astrophysics Data System (ADS)

Bencheikh, K.; Jankovic, A.; Symul, T.; Levenson, J. A.

2002-06-01

Nous avons élaboré un protocole de cryptographie quantique qui permet de générer et de distribuer une clé secrète aléatoire. Le protocole repose sur l'utilisation de paires de champs électromagnétiques dont les quadratures présentent des corrélations quantiques de type Einstein-Podolsky-Rosen. Les fluctuations quantiques instantanése constituent les bits aléatoires de la clé secrète, et la dégradation irréversible des corrélations quantiques des quadratures causée par une tierce personne permet de la détecter et de garantir la sécurité d'échange.

Continuous variable quantum key distribution: finite-key analysis of composable security against coherent attacks.

PubMed

Furrer, F; Franz, T; Berta, M; Leverrier, A; Scholz, V B; Tomamichel, M; Werner, R F

2012-09-07

We provide a security analysis for continuous variable quantum key distribution protocols based on the transmission of two-mode squeezed vacuum states measured via homodyne detection. We employ a version of the entropic uncertainty relation for smooth entropies to give a lower bound on the number of secret bits which can be extracted from a finite number of runs of the protocol. This bound is valid under general coherent attacks, and gives rise to keys which are composably secure. For comparison, we also give a lower bound valid under the assumption of collective attacks. For both scenarios, we find positive key rates using experimental parameters reachable today.

Experimental realization of equiangular three-state quantum key distribution

PubMed Central

Schiavon, Matteo; Vallone, Giuseppe; Villoresi, Paolo

2016-01-01

Quantum key distribution using three states in equiangular configuration combines a security threshold comparable with the one of the Bennett-Brassard 1984 protocol and a quantum bit error rate (QBER) estimation that does not need to reveal part of the key. We implement an entanglement-based version of the Renes 2004 protocol, using only passive optic elements in a linear scheme for the positive-operator valued measure (POVM), generating an asymptotic secure key rate of more than 10 kbit/s, with a mean QBER of 1.6%. We then demonstrate its security in the case of finite key and evaluate the key rate for both collective and general attacks. PMID:27465643

Quantum key distribution in a multi-user network at gigahertz clock rates

NASA Astrophysics Data System (ADS)

Fernandez, Veronica; Gordon, Karen J.; Collins, Robert J.; Townsend, Paul D.; Cova, Sergio D.; Rech, Ivan; Buller, Gerald S.

2005-07-01

In recent years quantum information research has lead to the discovery of a number of remarkable new paradigms for information processing and communication. These developments include quantum cryptography schemes that offer unconditionally secure information transport guaranteed by quantum-mechanical laws. Such potentially disruptive security technologies could be of high strategic and economic value in the future. Two major issues confronting researchers in this field are the transmission range (typically <100km) and the key exchange rate, which can be as low as a few bits per second at long optical fiber distances. This paper describes further research of an approach to significantly enhance the key exchange rate in an optical fiber system at distances in the range of 1-20km. We will present results on a number of application scenarios, including point-to-point links and multi-user networks. Quantum key distribution systems have been developed, which use standard telecommunications optical fiber, and which are capable of operating at clock rates of up to 2GHz. They implement a polarization-encoded version of the B92 protocol and employ vertical-cavity surface-emitting lasers with emission wavelengths of 850 nm as weak coherent light sources, as well as silicon single-photon avalanche diodes as the single photon detectors. The point-to-point quantum key distribution system exhibited a quantum bit error rate of 1.4%, and an estimated net bit rate greater than 100,000 bits-1 for a 4.2 km transmission range.

Quantum fingerprinting with coherent states and a constant mean number of photons

NASA Astrophysics Data System (ADS)

Arrazola, Juan Miguel; Lütkenhaus, Norbert

2014-06-01

We present a protocol for quantum fingerprinting that is ready to be implemented with current technology and is robust to experimental errors. The basis of our scheme is an implementation of the signal states in terms of a coherent state in a superposition of time-bin modes. Experimentally, this requires only the ability to prepare coherent states of low amplitude and to interfere them in a balanced beam splitter. The states used in the protocol are arbitrarily close in trace distance to states of O (log2n) qubits, thus exhibiting an exponential separation in abstract communication complexity compared to the classical case. The protocol uses a number of optical modes that is proportional to the size n of the input bit strings but a total mean photon number that is constant and independent of n. Given the expended resources, our protocol achieves a task that is provably impossible using classical communication only. In fact, even in the presence of realistic experimental errors and loss, we show that there exist a large range of input sizes for which our quantum protocol transmits an amount of information that can be more than two orders of magnitude smaller than a classical fingerprinting protocol.

Multi-Party Privacy-Preserving Set Intersection with Quasi-Linear Complexity

NASA Astrophysics Data System (ADS)

Cheon, Jung Hee; Jarecki, Stanislaw; Seo, Jae Hong

Secure computation of the set intersection functionality allows n parties to find the intersection between their datasets without revealing anything else about them. An efficient protocol for such a task could have multiple potential applications in commerce, health care, and security. However, all currently known secure set intersection protocols for n>2 parties have computational costs that are quadratic in the (maximum) number of entries in the dataset contributed by each party, making secure computation of the set intersection only practical for small datasets. In this paper, we describe the first multi-party protocol for securely computing the set intersection functionality with both the communication and the computation costs that are quasi-linear in the size of the datasets. For a fixed security parameter, our protocols require O(n2k) bits of communication and Õ(n2k) group multiplications per player in the malicious adversary setting, where k is the size of each dataset. Our protocol follows the basic idea of the protocol proposed by Kissner and Song, but we gain efficiency by using different representations of the polynomials associated with users' datasets and careful employment of algorithms that interpolate or evaluate polynomials on multiple points more efficiently. Moreover, the proposed protocol is robust. This means that the protocol outputs the desired result even if some corrupted players leave during the execution of the protocol.

Quantum steganography with large payload based on entanglement swapping of χ-type entangled states

NASA Astrophysics Data System (ADS)

Qu, Zhi-Guo; Chen, Xiu-Bo; Luo, Ming-Xing; Niu, Xin-Xin; Yang, Yi-Xian

2011-04-01

In this paper, we firstly propose a new simple method to calculate entanglement swapping of χ-type entangled states, and then present a novel quantum steganography protocol with large payload. The new protocol adopts entanglement swapping to build up the hidden channel within quantum secure direct communication with χ-type entangled states for securely transmitting secret messages. Comparing with the previous quantum steganographies, the capacity of the hidden channel is much higher, which is increased to eight bits. Meanwhile, due to the quantum uncertainty theorem and the no-cloning theorem its imperceptibility is proved to be great in the analysis, and its security is also analyzed in detail, which is proved that intercept-resend attack, measurement-resend attack, ancilla attack, man-in-the-middle attack or even Dos(Denial of Service) attack couldn't threaten it. As a result, the protocol can be applied in various fields of quantum communication.

Realistic noise-tolerant randomness amplification using finite number of devices.

PubMed

Brandão, Fernando G S L; Ramanathan, Ravishankar; Grudka, Andrzej; Horodecki, Karol; Horodecki, Michał; Horodecki, Paweł; Szarek, Tomasz; Wojewódka, Hanna

2016-04-21

Randomness is a fundamental concept, with implications from security of modern data systems, to fundamental laws of nature and even the philosophy of science. Randomness is called certified if it describes events that cannot be pre-determined by an external adversary. It is known that weak certified randomness can be amplified to nearly ideal randomness using quantum-mechanical systems. However, so far, it was unclear whether randomness amplification is a realistic task, as the existing proposals either do not tolerate noise or require an unbounded number of different devices. Here we provide an error-tolerant protocol using a finite number of devices for amplifying arbitrary weak randomness into nearly perfect random bits, which are secure against a no-signalling adversary. The correctness of the protocol is assessed by violating a Bell inequality, with the degree of violation determining the noise tolerance threshold. An experimental realization of the protocol is within reach of current technology.

Realistic noise-tolerant randomness amplification using finite number of devices

NASA Astrophysics Data System (ADS)

Brandão, Fernando G. S. L.; Ramanathan, Ravishankar; Grudka, Andrzej; Horodecki, Karol; Horodecki, Michał; Horodecki, Paweł; Szarek, Tomasz; Wojewódka, Hanna

2016-04-01

Randomness is a fundamental concept, with implications from security of modern data systems, to fundamental laws of nature and even the philosophy of science. Randomness is called certified if it describes events that cannot be pre-determined by an external adversary. It is known that weak certified randomness can be amplified to nearly ideal randomness using quantum-mechanical systems. However, so far, it was unclear whether randomness amplification is a realistic task, as the existing proposals either do not tolerate noise or require an unbounded number of different devices. Here we provide an error-tolerant protocol using a finite number of devices for amplifying arbitrary weak randomness into nearly perfect random bits, which are secure against a no-signalling adversary. The correctness of the protocol is assessed by violating a Bell inequality, with the degree of violation determining the noise tolerance threshold. An experimental realization of the protocol is within reach of current technology.

Experimental plug and play quantum coin flipping.

PubMed

Pappa, Anna; Jouguet, Paul; Lawson, Thomas; Chailloux, André; Legré, Matthieu; Trinkler, Patrick; Kerenidis, Iordanis; Diamanti, Eleni

2014-04-24

Performing complex cryptographic tasks will be an essential element in future quantum communication networks. These tasks are based on a handful of fundamental primitives, such as coin flipping, where two distrustful parties wish to agree on a randomly generated bit. Although it is known that quantum versions of these primitives can offer information-theoretic security advantages with respect to classical protocols, a demonstration of such an advantage in a practical communication scenario has remained elusive. Here we experimentally implement a quantum coin flipping protocol that performs strictly better than classically possible over a distance suitable for communication over metropolitan area optical networks. The implementation is based on a practical plug and play system, developed by significantly enhancing a commercial quantum key distribution device. Moreover, we provide combined quantum coin flipping protocols that are almost perfectly secure against bounded adversaries. Our results offer a useful toolbox for future secure quantum communications.

Design and implementation of a telemedicine system using Bluetooth protocol and GSM/GPRS network, for real time remote patient monitoring.

PubMed

Jasemian, Yousef; Nielsen, Lars Arendt

2005-01-01

This paper introduces the design and implementation of a generic wireless and Real-time Multi-purpose Health Care Telemedicine system applying Bluetooth protocol, Global System for Mobile Communications (GSM) and General Packet Radio Service (GPRS). The paper explores the factors that should be considered when evaluating different technologies for application in telemedicine system. The design and implementation of an embedded wireless communication platform utilising Bluetooth protocol is described, and the implementation problems and limitations are investigated. The system is tested and its telecommunication general aspects are verified. The results showed that the system has (97.9 +/- 1.3)% Up-time, 2.5 x 10(-5) Bit Error Rate, 1% Dropped Call Rate, 97.4% Call Success Rate, 5 second transmission delay in average, (3.42 +/- 0.11) kbps throughput, and the system may have application in electrocardiography.

Experimental study on all-fiber-based unidimensional continuous-variable quantum key distribution

NASA Astrophysics Data System (ADS)

Wang, Xuyang; Liu, Wenyuan; Wang, Pu; Li, Yongmin

2017-06-01

We experimentally demonstrated an all-fiber-based unidimensional continuous-variable quantum key distribution (CV QKD) protocol and analyzed its security under collective attack in realistic conditions. A pulsed balanced homodyne detector, which could not be accessed by eavesdroppers, with phase-insensitive efficiency and electronic noise, was considered. Furthermore, a modulation method and an improved relative phase-locking technique with one amplitude modulator and one phase modulator were designed. The relative phase could be locked precisely with a standard deviation of 0.5° and a mean of almost zero. Secret key bit rates of 5.4 kbps and 700 bps were achieved for transmission fiber lengths of 30 and 50 km, respectively. The protocol, which simplified the CV QKD system and reduced the cost, displayed a performance comparable to that of a symmetrical counterpart under realistic conditions. It is expected that the developed protocol can facilitate the practical application of the CV QKD.

Realistic noise-tolerant randomness amplification using finite number of devices

PubMed Central

Brandão, Fernando G. S. L.; Ramanathan, Ravishankar; Grudka, Andrzej; Horodecki, Karol; Horodecki, Michał; Horodecki, Paweł; Szarek, Tomasz; Wojewódka, Hanna

2016-01-01

Randomness is a fundamental concept, with implications from security of modern data systems, to fundamental laws of nature and even the philosophy of science. Randomness is called certified if it describes events that cannot be pre-determined by an external adversary. It is known that weak certified randomness can be amplified to nearly ideal randomness using quantum-mechanical systems. However, so far, it was unclear whether randomness amplification is a realistic task, as the existing proposals either do not tolerate noise or require an unbounded number of different devices. Here we provide an error-tolerant protocol using a finite number of devices for amplifying arbitrary weak randomness into nearly perfect random bits, which are secure against a no-signalling adversary. The correctness of the protocol is assessed by violating a Bell inequality, with the degree of violation determining the noise tolerance threshold. An experimental realization of the protocol is within reach of current technology. PMID:27098302

Silicon microdisk-based full adders for optical computing.

PubMed

Ying, Zhoufeng; Wang, Zheng; Zhao, Zheng; Dhar, Shounak; Pan, David Z; Soref, Richard; Chen, Ray T

2018-03-01

Due to the projected saturation of Moore's law, as well as the drastically increasing trend of bandwidth with lower power consumption, silicon photonics has emerged as one of the most promising alternatives that has attracted a lasting interest due to the accessibility and maturity of ultra-compact passive and active integrated photonic components. In this Letter, we demonstrate a ripple-carry electro-optic 2-bit full adder using microdisks, which replaces the core part of an electrical full adder by optical counterparts and uses light to carry signals from one bit to the next with high bandwidth and low power consumption per bit. All control signals of the operands are applied simultaneously within each clock cycle. Thus, the severe latency issue that accumulates as the size of the full adder increases can be circumvented, allowing for an improvement in computing speed and a reduction in power consumption. This approach paves the way for future high-speed optical computing systems in the post-Moore's law era.

A microprocessor based on a two-dimensional semiconductor

PubMed Central

Wachter, Stefan; Polyushkin, Dmitry K.; Bethge, Ole; Mueller, Thomas

2017-01-01

The advent of microcomputers in the 1970s has dramatically changed our society. Since then, microprocessors have been made almost exclusively from silicon, but the ever-increasing demand for higher integration density and speed, lower power consumption and better integrability with everyday goods has prompted the search for alternatives. Germanium and III–V compound semiconductors are being considered promising candidates for future high-performance processor generations and chips based on thin-film plastic technology or carbon nanotubes could allow for embedding electronic intelligence into arbitrary objects for the Internet-of-Things. Here, we present a 1-bit implementation of a microprocessor using a two-dimensional semiconductor—molybdenum disulfide. The device can execute user-defined programs stored in an external memory, perform logical operations and communicate with its periphery. Our 1-bit design is readily scalable to multi-bit data. The device consists of 115 transistors and constitutes the most complex circuitry so far made from a two-dimensional material. PMID:28398336

Development of elastomeric isolators to reduce roof bolting machine drilling noise

PubMed Central

Michael, Robert; Yantek, David; Johnson, David; Ferro, Ernie; Swope, Chad

2015-01-01

Among underground coal miners, hearing loss remains one of the most common occupational illnesses. In response to this problem, the National Institute for Occupational Safety and Health (NIOSH) Office of Mine Safety and Health Research (OMSHR) conducts research to reduce the noise emission of underground coal-mining equipment, an example of which is a roof bolting machine. Field studies show that, on average, drilling noise is the most significant contributor to a roof bolting machine operator’s noise exposure. NIOSH OMSHR has determined that the drill steel and chuck are the dominant sources of drilling noise. NIOSH OMSHR, Corry Rubber Corporation, and Kennametal, Inc. have developed a bit isolator that breaks the steel-to-steel link between the drill bit and drill steel and a chuck isolator that breaks the mechanical connection between the drill steel and the chuck, thus reducing the noise radiated by the drill steel and chuck, and the noise exposure of the roof bolter operator. This paper documents the evolution of the bit isolator and chuck isolator including various alternative designs which may enhance performance. Laboratory testing confirms that production bit and chuck isolators reduce the A-weighted sound level generated during drilling by 3.7 to 6.6 dB. Finally, this paper summarizes results of a finite element analysis used to explore the key parameters of the drill bit isolator and chuck isolator to understand the impact these parameters have on noise. PMID:26568650

A new display stream compression standard under development in VESA

NASA Astrophysics Data System (ADS)

Jacobson, Natan; Thirumalai, Vijayaraghavan; Joshi, Rajan; Goel, James

2017-09-01

The Advanced Display Stream Compression (ADSC) codec project is in development in response to a call for technologies from the Video Electronics Standards Association (VESA). This codec targets visually lossless compression of display streams at a high compression rate (typically 6 bits/pixel) for mobile/VR/HDR applications. Functionality of the ADSC codec is described in this paper, and subjective trials results are provided using the ISO 29170-2 testing protocol.

MIL-STD-1553B Marconi LSI chip set in a remote terminal application

NASA Astrophysics Data System (ADS)

Dimarino, A.

1982-11-01

Marconi Avionics is utilizing the MIL-STD-1553B LSI Chip Set in the SCADC Air Data Computer application to perform all of the required remote terminal MIL-STD-1553B protocol functions. Basic components of the RTU are the dual redundant chip set, CT3231 Transceivers, 256 x 16 RAM and a Z8002 microprocessor. Basic transfers are to/from the RAM command of the bus controller or Z8002 processor. During transfers from the processor to the RAM, the chip set busy bit is set for a period not exceeding 250 microseconds. When the transfer is complete, the busy bit is released and transfers to the data bus occur on command. The LSI Chip Set word count lines are used to locate each data word in the local memory and 4 mode codes are used in the application: reset remote terminal, transmit status word, transmitter shut-down, and override transmitter shutdown.

Variable-bias coin tossing

NASA Astrophysics Data System (ADS)

Colbeck, Roger; Kent, Adrian

2006-03-01

Alice is a charismatic quantum cryptographer who believes her parties are unmissable; Bob is a (relatively) glamorous string theorist who believes he is an indispensable guest. To prevent possibly traumatic collisions of self-perception and reality, their social code requires that decisions about invitation or acceptance be made via a cryptographically secure variable-bias coin toss (VBCT). This generates a shared random bit by the toss of a coin whose bias is secretly chosen, within a stipulated range, by one of the parties; the other party learns only the random bit. Thus one party can secretly influence the outcome, while both can save face by blaming any negative decisions on bad luck. We describe here some cryptographic VBCT protocols whose security is guaranteed by quantum theory and the impossibility of superluminal signaling, setting our results in the context of a general discussion of secure two-party computation. We also briefly discuss other cryptographic applications of VBCT.

Traffic Management in ATM Networks Over Satellite Links

NASA Technical Reports Server (NTRS)

Goyal, Rohit; Jain, Raj; Goyal, Mukul; Fahmy, Sonia; Vandalore, Bobby; vonDeak, Thomas

1999-01-01

This report presents a survey of the traffic management Issues in the design and implementation of satellite Asynchronous Transfer Mode (ATM) networks. The report focuses on the efficient transport of Transmission Control Protocol (TCP) traffic over satellite ATM. First, a reference satellite ATM network architecture is presented along with an overview of the service categories available in ATM networks. A delay model for satellite networks and the major components of delay and delay variation are described. A survey of design options for TCP over Unspecified Bit Rate (UBR), Guaranteed Frame Rate (GFR) and Available Bit Rate (ABR) services in ATM is presented. The main focus is on traffic management issues. Several recommendations on the design options for efficiently carrying data services over satellite ATM networks are presented. Most of the results are based on experiments performed on Geosynchronous (GEO) latencies. Some results for Low Earth Orbits (LEO) and Medium Earth Orbit (MEO) latencies are also provided.

Neural network based feed-forward high density associative memory

NASA Technical Reports Server (NTRS)

Daud, T.; Moopenn, A.; Lamb, J. L.; Ramesham, R.; Thakoor, A. P.

1987-01-01

A novel thin film approach to neural-network-based high-density associative memory is described. The information is stored locally in a memory matrix of passive, nonvolatile, binary connection elements with a potential to achieve a storage density of 10 to the 9th bits/sq cm. Microswitches based on memory switching in thin film hydrogenated amorphous silicon, and alternatively in manganese oxide, have been used as programmable read-only memory elements. Low-energy switching has been ascertained in both these materials. Fabrication and testing of memory matrix is described. High-speed associative recall approaching 10 to the 7th bits/sec and high storage capacity in such a connection matrix memory system is also described.

False Operation of Static Random Access Memory Cells under Alternating Current Power Supply Voltage Variation

NASA Astrophysics Data System (ADS)

Sawada, Takuya; Takata, Hidehiro; Nii, Koji; Nagata, Makoto

2013-04-01

Static random access memory (SRAM) cores exhibit susceptibility against power supply voltage variation. False operation is investigated among SRAM cells under sinusoidal voltage variation on power lines introduced by direct RF power injection. A standard SRAM core of 16 kbyte in a 90 nm 1.5 V technology is diagnosed with built-in self test and on-die noise monitor techniques. The sensitivity of bit error rate is shown to be high against the frequency of injected voltage variation, while it is not greatly influenced by the difference in frequency and phase against SRAM clocking. It is also observed that the distribution of false bits is substantially random in a cell array.

LANDSAT D local user terminal study

NASA Technical Reports Server (NTRS)

Alexander, L.; Louie, M.; Spencer, R.; Stow, W. K.

1976-01-01

The effect of the changes incorporated in the LANDSAT D system on the ability of a local user terminal to receive, record and process data in real time was studied. Alternate solutions to the problems raised by these changes were evaluated. A loading analysis was performed in order to determine the quantities of data that a local user terminal (LUT) would be interested in receiving and processing. The number of bits in an MSS and a TM scene were calculated along with the number of scenes per day that an LUT might require for processing. These then combined to a total number of processed bits/day for an LUT as a function of sensor and coverage circle radius.

Position-based coding and convex splitting for private communication over quantum channels

NASA Astrophysics Data System (ADS)

Wilde, Mark M.

2017-10-01

The classical-input quantum-output (cq) wiretap channel is a communication model involving a classical sender X, a legitimate quantum receiver B, and a quantum eavesdropper E. The goal of a private communication protocol that uses such a channel is for the sender X to transmit a message in such a way that the legitimate receiver B can decode it reliably, while the eavesdropper E learns essentially nothing about which message was transmitted. The ɛ -one-shot private capacity of a cq wiretap channel is equal to the maximum number of bits that can be transmitted over the channel, such that the privacy error is no larger than ɛ \\in (0,1). The present paper provides a lower bound on the ɛ -one-shot private classical capacity, by exploiting the recently developed techniques of Anshu, Devabathini, Jain, and Warsi, called position-based coding and convex splitting. The lower bound is equal to a difference of the hypothesis testing mutual information between X and B and the "alternate" smooth max-information between X and E. The one-shot lower bound then leads to a non-trivial lower bound on the second-order coding rate for private classical communication over a memoryless cq wiretap channel.

A Bit More to It: Scholarly Communication Forums as Socio-Technical Interaction Networks.

ERIC Educational Resources Information Center

Kling, Rob; McKim, Geoffrey; King, Adam

2003-01-01

Examines the conceptual models that help to understand the development and sustainability of scholarly and professional communication forums on the Internet. An alternative information processing model that considers information technologies as Socio-Technical Interaction Networks (STINs) and a method for modeling electronic forums as STINs are…

Demonstration of optical computing logics based on binary decision diagram.

PubMed

Lin, Shiyun; Ishikawa, Yasuhiko; Wada, Kazumi

2012-01-16

Optical circuits are low power consumption and fast speed alternatives for the current information processing based on transistor circuits. However, because of no transistor function available in optics, the architecture for optical computing should be chosen that optics prefers. One of which is Binary Decision Diagram (BDD), where signal is processed by sending an optical signal from the root through a serial of switching nodes to the leaf (terminal). Speed of optical computing is limited by either transmission time of optical signals from the root to the leaf or switching time of a node. We have designed and experimentally demonstrated 1-bit and 2-bit adders based on the BDD architecture. The switching nodes are silicon ring resonators with a modulation depth of 10 dB and the states are changed by the plasma dispersion effect. The quality, Q of the rings designed is 1500, which allows fast transmission of signal, e.g., 1.3 ps calculated by a photon escaping time. A total processing time is thus analyzed to be ~9 ps for a 2-bit adder and would scales linearly with the number of bit. It is two orders of magnitude faster than the conventional CMOS circuitry, ~ns scale of delay. The presented results show the potential of fast speed optical computing circuits.

Temporal steering and security of quantum key distribution with mutually unbiased bases against individual attacks

NASA Astrophysics Data System (ADS)

Bartkiewicz, Karol; Černoch, Antonín; Lemr, Karel; Miranowicz, Adam; Nori, Franco

2016-06-01

Temporal steering, which is a temporal analog of Einstein-Podolsky-Rosen steering, refers to temporal quantum correlations between the initial and final state of a quantum system. Our analysis of temporal steering inequalities in relation to the average quantum bit error rates reveals the interplay between temporal steering and quantum cloning, which guarantees the security of quantum key distribution based on mutually unbiased bases against individual attacks. The key distributions analyzed here include the Bennett-Brassard 1984 protocol and the six-state 1998 protocol by Bruss. Moreover, we define a temporal steerable weight, which enables us to identify a kind of monogamy of temporal correlation that is essential to quantum cryptography and useful for analyzing various scenarios of quantum causality.

Use of a Microprocessor to Implement an ADCCP Protocol (Federal Std-1003) Operating in the Unbalanced Normal Mode.

DTIC Science & Technology

1980-05-01

andcoptrpormigfrteublne nra ls fpoeue nacrac with Federal Standard 1003 fTelecommunications: Synchronous Bit Oriented Data Link Control Procedures...and the higher level user. The solution to the producer/consumer problem involves the use of PASS and SICHAL primitives and event variables or... semaphores . The event variables have been defined for the LS-microprocessor interface as part of I-1 the internal registers that are included in the F6856

Coherent communication with continuous quantum variables

NASA Astrophysics Data System (ADS)

Wilde, Mark M.; Krovi, Hari; Brun, Todd A.

2007-06-01

The coherent bit (cobit) channel is a resource intermediate between classical and quantum communication. It produces coherent versions of teleportation and superdense coding. We extend the cobit channel to continuous variables by providing a definition of the coherent nat (conat) channel. We construct several coherent protocols that use both a position-quadrature and a momentum-quadrature conat channel with finite squeezing. Finally, we show that the quality of squeezing diminishes through successive compositions of coherent teleportation and superdense coding.

A Rate-Based Congestion Control Algorithm for the SURAP 4 Packet Radio Architecture (SRNTN-72)

DTIC Science & Technology

1990-01-01

factor, one packet. as at connection initialization. However. these TCP enhancements do not solve the fairness problem. The slow start algorithm ma...and signal interference (including lamming) and by the delavs demanded b% the hink -layer protocols in the absence of contention for resources at the...values. This role would be redundant if bits-per-second rations used measurements of packet duration to determine how fast to decrease, at the expense of

Design Issues for Traffic Management for the ATM UBR + Service for TCP Over Satellite Networks

NASA Technical Reports Server (NTRS)

Jain, Raj

1999-01-01

This project was a comprehensive research program for developing techniques for improving the performance of Internet protocols over Asynchronous Transfer Mode (ATM) based satellite networks. Among the service categories provided by ATM networks, the most commonly used category for data traffic is the unspecified bit rate (UBR) service. UBR allows sources to send data into the network without any feedback control. The project resulted in the numerous ATM Forum contributions and papers.

A potent approach for the development of FPGA based DAQ system for HEP experiments

NASA Astrophysics Data System (ADS)

Khan, Shuaib Ahmad; Mitra, Jubin; David, Erno; Kiss, Tivadar; Nayak, Tapan Kumar

2017-10-01

With ever increasing particle beam energies and interaction rates in modern High Energy Physics (HEP) experiments in the present and future accelerator facilities, there has always been the demand for robust Data Acquisition (DAQ) schemes which perform in the harsh radiation environment and handle high data volume. The scheme is required to be flexible enough to adapt to the demands of future detector and electronics upgrades, and at the same time keeping the cost factor in mind. To address these challenges, in the present work, we discuss an efficient DAQ scheme for error resilient, high speed data communication on commercially available state-of-the-art FPGA with optical links. The scheme utilises GigaBit Transceiver (GBT) protocol to establish radiation tolerant communication link between on-detector front-end electronics situated in harsh radiation environment to the back-end Data Processing Unit (DPU) placed in a low radiation zone. The acquired data are reconstructed in DPU which reduces the data volume significantly, and then transmitted to the computing farms through high speed optical links using 10 Gigabit Ethernet (10GbE). In this study, we focus on implementation and testing of GBT protocol and 10GbE links on an Intel FPGA. Results of the measurements of resource utilisation, critical path delays, signal integrity, eye diagram and Bit Error Rate (BER) are presented, which are the indicators for efficient system performance.

Nanofabrication of Gate-defined GaAs/AlGaAs Lateral Quantum Dots

PubMed Central

Bureau-Oxton, Chloé; Camirand Lemyre, Julien; Pioro-Ladrière, Michel

2013-01-01

A quantum computer is a computer composed of quantum bits (qubits) that takes advantage of quantum effects, such as superposition of states and entanglement, to solve certain problems exponentially faster than with the best known algorithms on a classical computer. Gate-defined lateral quantum dots on GaAs/AlGaAs are one of many avenues explored for the implementation of a qubit. When properly fabricated, such a device is able to trap a small number of electrons in a certain region of space. The spin states of these electrons can then be used to implement the logical 0 and 1 of the quantum bit. Given the nanometer scale of these quantum dots, cleanroom facilities offering specialized equipment- such as scanning electron microscopes and e-beam evaporators- are required for their fabrication. Great care must be taken throughout the fabrication process to maintain cleanliness of the sample surface and to avoid damaging the fragile gates of the structure. This paper presents the detailed fabrication protocol of gate-defined lateral quantum dots from the wafer to a working device. Characterization methods and representative results are also briefly discussed. Although this paper concentrates on double quantum dots, the fabrication process remains the same for single or triple dots or even arrays of quantum dots. Moreover, the protocol can be adapted to fabricate lateral quantum dots on other substrates, such as Si/SiGe. PMID:24300661

Physical layer one-time-pad data encryption through synchronized semiconductor laser networks

NASA Astrophysics Data System (ADS)

Argyris, Apostolos; Pikasis, Evangelos; Syvridis, Dimitris

2016-02-01

Semiconductor lasers (SL) have been proven to be a key device in the generation of ultrafast true random bit streams. Their potential to emit chaotic signals under conditions with desirable statistics, establish them as a low cost solution to cover various needs, from large volume key generation to real-time encrypted communications. Usually, only undemanding post-processing is needed to convert the acquired analog timeseries to digital sequences that pass all established tests of randomness. A novel architecture that can generate and exploit these true random sequences is through a fiber network in which the nodes are semiconductor lasers that are coupled and synchronized to central hub laser. In this work we show experimentally that laser nodes in such a star network topology can synchronize with each other through complex broadband signals that are the seed to true random bit sequences (TRBS) generated at several Gb/s. The potential for each node to access real-time generated and synchronized with the rest of the nodes random bit streams, through the fiber optic network, allows to implement an one-time-pad encryption protocol that mixes the synchronized true random bit sequence with real data at Gb/s rates. Forward-error correction methods are used to reduce the errors in the TRBS and the final error rate at the data decoding level. An appropriate selection in the sampling methodology and properties, as well as in the physical properties of the chaotic seed signal through which network locks in synchronization, allows an error free performance.

Electronic Photography at the NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Holm, Jack; Judge, Nancianne

1995-01-01

An electronic photography facility has been established in the Imaging & Photographic Technology Section, Visual Imaging Branch, at the NASA Langley Research Center (LaRC). The purpose of this facility is to provide the LaRC community with access to digital imaging technology. In particular, capabilities have been established for image scanning, direct image capture, optimized image processing for storage, image enhancement, and optimized device dependent image processing for output. Unique approaches include: evaluation and extraction of the entire film information content through scanning; standardization of image file tone reproduction characteristics for optimal bit utilization and viewing; education of digital imaging personnel on the effects of sampling and quantization to minimize image processing related information loss; investigation of the use of small kernel optimal filters for image restoration; characterization of a large array of output devices and development of image processing protocols for standardized output. Currently, the laboratory has a large collection of digital image files which contain essentially all the information present on the original films. These files are stored at 8-bits per color, but the initial image processing was done at higher bit depths and/or resolutions so that the full 8-bits are used in the stored files. The tone reproduction of these files has also been optimized so the available levels are distributed according to visual perceptibility. Look up tables are available which modify these files for standardized output on various devices, although color reproduction has been allowed to float to some extent to allow for full utilization of output device gamut.

A Quantum Private Query Protocol for Enhancing both User and Database Privacy

NASA Astrophysics Data System (ADS)

Zhou, Yi-Hua; Bai, Xue-Wei; Li, Lei-Lei; Shi, Wei-Min; Yang, Yu-Guang

2018-01-01

In order to protect the privacy of query user and database, some QKD-based quantum private query (QPQ) protocols were proposed. Unfortunately some of them cannot resist internal attack from database perfectly; some others can ensure better user privacy but require a reduction of database privacy. In this paper, a novel two-way QPQ protocol is proposed to ensure the privacy of both sides of communication. In our protocol, user makes initial quantum states and derives the key bit by comparing initial quantum state and outcome state returned from database by ctrl or shift mode instead of announcing two non-orthogonal qubits as others which may leak part secret information. In this way, not only the privacy of database be ensured but also user privacy is strengthened. Furthermore, our protocol can also realize the security of loss-tolerance, cheat-sensitive, and resisting JM attack etc. Supported by National Natural Science Foundation of China under Grant Nos. U1636106, 61572053, 61472048, 61602019, 61502016; Beijing Natural Science Foundation under Grant Nos. 4152038, 4162005; Basic Research Fund of Beijing University of Technology (No. X4007999201501); The Scientific Research Common Program of Beijing Municipal Commission of Education under Grant No. KM201510005016

Quantum protocols within Spekkens' toy model

NASA Astrophysics Data System (ADS)

Disilvestro, Leonardo; Markham, Damian

2017-05-01

Quantum mechanics is known to provide significant improvements in information processing tasks when compared to classical models. These advantages range from computational speedups to security improvements. A key question is where these advantages come from. The toy model developed by Spekkens [R. W. Spekkens, Phys. Rev. A 75, 032110 (2007), 10.1103/PhysRevA.75.032110] mimics many of the features of quantum mechanics, such as entanglement and no cloning, regarded as being important in this regard, despite being a local hidden variable theory. In this work, we study several protocols within Spekkens' toy model where we see it can also mimic the advantages and limitations shown in the quantum case. We first provide explicit proofs for the impossibility of toy bit commitment and the existence of a toy error correction protocol and consequent k -threshold secret sharing. Then, defining a toy computational model based on the quantum one-way computer, we prove the existence of blind and verified protocols. Importantly, these two last quantum protocols are known to achieve a better-than-classical security. Our results suggest that such quantum improvements need not arise from any Bell-type nonlocality or contextuality, but rather as a consequence of steering correlations.

Fair loss-tolerant quantum coin flipping

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berlin, Guido; Brassard, Gilles; Bussieres, Felix

Coin flipping is a cryptographic primitive in which two spatially separated players, who do not trust each other, wish to establish a common random bit. If we limit ourselves to classical communication, this task requires either assumptions on the computational power of the players or it requires them to send messages to each other with sufficient simultaneity to force their complete independence. Without such assumptions, all classical protocols are so that one dishonest player has complete control over the outcome. If we use quantum communication, on the other hand, protocols have been introduced that limit the maximal bias that dishonestmore » players can produce. However, those protocols would be very difficult to implement in practice because they are susceptible to realistic losses on the quantum channel between the players or in their quantum memory and measurement apparatus. In this paper, we introduce a quantum protocol and we prove that it is completely impervious to loss. The protocol is fair in the sense that either player has the same probability of success in cheating attempts at biasing the outcome of the coin flip. We also give explicit and optimal cheating strategies for both players.« less

Polarization entanglement purification for concatenated Greenberger-Horne-Zeilinger state

NASA Astrophysics Data System (ADS)

Zhou, Lan; Sheng, Yu-Bo

2017-10-01

Entanglement purification plays a fundamental role in long-distance quantum communication. In the paper, we put forward the first polarization entanglement purification protocol (EPP) for one type of nonlocal logic-qubit entanglement, i.e., concatenated Greenberger-Horne-Zeilinger (C-GHZ) state, resorting to the photon-atom interaction in low-quality (Q) cavity. In contrast to existing EPPs, this protocol can purify the bit-flip error and phase-flip error in both physic and logic level. Instead of measuring the photons directly, this protocol only requires to measure the atom states to judge whether the protocol is successful. In this way, the purified logic entangled states can be preserved for further application. Moreover, it makes this EPP repeatable so as to obtain a higher fidelity of logic entangled states. As the logic-qubit entanglement utilizes the quantum error correction (QEC) codes, which has an inherent stability against noise and decoherence, this EPP combined with the QEC codes may provide a double protection for the entanglement from the channel noise and may have potential applications in long-distance quantum communication.

Robust general N user authentication scheme in a centralized quantum communication network via generalized GHZ states

NASA Astrophysics Data System (ADS)

Farouk, Ahmed; Batle, J.; Elhoseny, M.; Naseri, Mosayeb; Lone, Muzaffar; Fedorov, Alex; Alkhambashi, Majid; Ahmed, Syed Hassan; Abdel-Aty, M.

2018-04-01

Quantum communication provides an enormous advantage over its classical counterpart: security of communications based on the very principles of quantum mechanics. Researchers have proposed several approaches for user identity authentication via entanglement. Unfortunately, these protocols fail because an attacker can capture some of the particles in a transmitted sequence and send what is left to the receiver through a quantum channel. Subsequently, the attacker can restore some of the confidential messages, giving rise to the possibility of information leakage. Here we present a new robust General N user authentication protocol based on N-particle Greenberger-Horne-Zeilinger (GHZ) states, which makes eavesdropping detection more effective and secure, as compared to some current authentication protocols. The security analysis of our protocol for various kinds of attacks verifies that it is unconditionally secure, and that an attacker will not obtain any information about the transmitted key. Moreover, as the number of transferred key bits N becomes larger, while the number of users for transmitting the information is increased, the probability of effectively obtaining the transmitted authentication keys is reduced to zero.

A Key Establishment Protocol for RFID User in IPTV Environment

NASA Astrophysics Data System (ADS)

Jeong, Yoon-Su; Kim, Yong-Tae; Sohn, Jae-Min; Park, Gil-Cheol; Lee, Sang-Ho

In recent years, the usage of IPTV (Internet Protocol Television) has been increased. The reason is a technological convergence of broadcasting and telecommunication delivering interactive applications and multimedia content through high speed Internet connections. The main critical point of IPTV security requirements is subscriber authentication. That is, IPTV service should have the capability to identify the subscribers to prohibit illegal access. Currently, IPTV service does not provide a sound authentication mechanism to verify the identity of its wireless users (or devices). This paper focuses on a lightweight authentication and key establishment protocol based on the use of hash functions. The proposed approach provides effective authentication for a mobile user with a RFID tag whose authentication information is communicated back and forth with the IPTV authentication server via IPTV set-top box (STB). That is, the proposed protocol generates user's authentication information that is a bundle of two public keys derived from hashing user's private keys and RFID tag's session identifier, and adds 1bit to this bundled information for subscriber's information confidentiality before passing it to the authentication server.

Optimization of oligonucleotide arrays and RNA amplification protocols for analysis of transcript structure and alternative splicing.

PubMed

Castle, John; Garrett-Engele, Phil; Armour, Christopher D; Duenwald, Sven J; Loerch, Patrick M; Meyer, Michael R; Schadt, Eric E; Stoughton, Roland; Parrish, Mark L; Shoemaker, Daniel D; Johnson, Jason M

2003-01-01

Microarrays offer a high-resolution means for monitoring pre-mRNA splicing on a genomic scale. We have developed a novel, unbiased amplification protocol that permits labeling of entire transcripts. Also, hybridization conditions, probe characteristics, and analysis algorithms were optimized for detection of exons, exon-intron edges, and exon junctions. These optimized protocols can be used to detect small variations and isoform mixtures, map the tissue specificity of known human alternative isoforms, and provide a robust, scalable platform for high-throughput discovery of alternative splicing.

Optimization of oligonucleotide arrays and RNA amplification protocols for analysis of transcript structure and alternative splicing

PubMed Central

Castle, John; Garrett-Engele, Phil; Armour, Christopher D; Duenwald, Sven J; Loerch, Patrick M; Meyer, Michael R; Schadt, Eric E; Stoughton, Roland; Parrish, Mark L; Shoemaker, Daniel D; Johnson, Jason M

2003-01-01

Microarrays offer a high-resolution means for monitoring pre-mRNA splicing on a genomic scale. We have developed a novel, unbiased amplification protocol that permits labeling of entire transcripts. Also, hybridization conditions, probe characteristics, and analysis algorithms were optimized for detection of exons, exon-intron edges, and exon junctions. These optimized protocols can be used to detect small variations and isoform mixtures, map the tissue specificity of known human alternative isoforms, and provide a robust, scalable platform for high-throughput discovery of alternative splicing. PMID:14519201

The Deterministic Information Bottleneck

NASA Astrophysics Data System (ADS)

Strouse, D. J.; Schwab, David

2015-03-01

A fundamental and ubiquitous task that all organisms face is prediction of the future based on past sensory experience. Since an individual's memory resources are limited and costly, however, there is a tradeoff between memory cost and predictive payoff. The information bottleneck (IB) method (Tishby, Pereira, & Bialek 2000) formulates this tradeoff as a mathematical optimization problem using an information theoretic cost function. IB encourages storing as few bits of past sensory input as possible while selectively preserving the bits that are most predictive of the future. Here we introduce an alternative formulation of the IB method, which we call the deterministic information bottleneck (DIB). First, we argue for an alternative cost function, which better represents the biologically-motivated goal of minimizing required memory resources. Then, we show that this seemingly minor change has the dramatic effect of converting the optimal memory encoder from stochastic to deterministic. Next, we propose an iterative algorithm for solving the DIB problem. Additionally, we compare the IB and DIB methods on a variety of synthetic datasets, and examine the performance of retinal ganglion cell populations relative to the optimal encoding strategy for each problem.

Robustness of spiking Deep Belief Networks to noise and reduced bit precision of neuro-inspired hardware platforms.

PubMed

Stromatias, Evangelos; Neil, Daniel; Pfeiffer, Michael; Galluppi, Francesco; Furber, Steve B; Liu, Shih-Chii

2015-01-01

Increasingly large deep learning architectures, such as Deep Belief Networks (DBNs) are the focus of current machine learning research and achieve state-of-the-art results in different domains. However, both training and execution of large-scale Deep Networks require vast computing resources, leading to high power requirements and communication overheads. The on-going work on design and construction of spike-based hardware platforms offers an alternative for running deep neural networks with significantly lower power consumption, but has to overcome hardware limitations in terms of noise and limited weight precision, as well as noise inherent in the sensor signal. This article investigates how such hardware constraints impact the performance of spiking neural network implementations of DBNs. In particular, the influence of limited bit precision during execution and training, and the impact of silicon mismatch in the synaptic weight parameters of custom hybrid VLSI implementations is studied. Furthermore, the network performance of spiking DBNs is characterized with regard to noise in the spiking input signal. Our results demonstrate that spiking DBNs can tolerate very low levels of hardware bit precision down to almost two bits, and show that their performance can be improved by at least 30% through an adapted training mechanism that takes the bit precision of the target platform into account. Spiking DBNs thus present an important use-case for large-scale hybrid analog-digital or digital neuromorphic platforms such as SpiNNaker, which can execute large but precision-constrained deep networks in real time.

Robustness of spiking Deep Belief Networks to noise and reduced bit precision of neuro-inspired hardware platforms

PubMed Central

Stromatias, Evangelos; Neil, Daniel; Pfeiffer, Michael; Galluppi, Francesco; Furber, Steve B.; Liu, Shih-Chii

2015-01-01

Increasingly large deep learning architectures, such as Deep Belief Networks (DBNs) are the focus of current machine learning research and achieve state-of-the-art results in different domains. However, both training and execution of large-scale Deep Networks require vast computing resources, leading to high power requirements and communication overheads. The on-going work on design and construction of spike-based hardware platforms offers an alternative for running deep neural networks with significantly lower power consumption, but has to overcome hardware limitations in terms of noise and limited weight precision, as well as noise inherent in the sensor signal. This article investigates how such hardware constraints impact the performance of spiking neural network implementations of DBNs. In particular, the influence of limited bit precision during execution and training, and the impact of silicon mismatch in the synaptic weight parameters of custom hybrid VLSI implementations is studied. Furthermore, the network performance of spiking DBNs is characterized with regard to noise in the spiking input signal. Our results demonstrate that spiking DBNs can tolerate very low levels of hardware bit precision down to almost two bits, and show that their performance can be improved by at least 30% through an adapted training mechanism that takes the bit precision of the target platform into account. Spiking DBNs thus present an important use-case for large-scale hybrid analog-digital or digital neuromorphic platforms such as SpiNNaker, which can execute large but precision-constrained deep networks in real time. PMID:26217169

Error rate performance of atmospheric laser communication based on bubble model

NASA Astrophysics Data System (ADS)

Xu, Ke; Wang, Jin; Li, Yan

2009-08-01

Free-Space Optics (FSO) can provide an effective line-of-sight and wireless communication with high bandwidth over a short distance. As a promising field of wireless communication, FSO is being accepted as an alternative of the more expensive fiber-optic based solutions. Despite the advantages of FSO, atmospheric turbulence has a significant impact on laser beam propagating through the channel in the atmosphere over a long distance. Turbulent eddies of various size and refractive index result in intensity scintillation and phase wander, which can severely impair the quality of FSO communication system. In this paper, a new geometrical model is used to assess the effects of turbulence on laser beam in its propagation path. The atmosphere is modeled along the transmission path filled with spatial-distributed spherical bubbles. The size and refractive index discontinuity of each bubble is K-distributed. This Monte Carlo technique allows us to estimate the fluctuation of intensity and phase shifts along the path. A pair of uncollimated rays arrives at the receiver through different path, and an optical path difference is produced. This difference causes a delay between the two rays. At the receiver, as the two rays are superposed, the delay ultimately affects the judgement of the bits. In the simulation, we assume that when the delay exceeds half of the bit width, bit error is possible. On the contrary, when the delay is less than the bit width, the bit error will not happen. Based on this assumption, we calculate the BER under different conditions, and results are further analyzed.

High-resolution LCOS microdisplay with sub-kHz frame rate for high performance, high precision 3D sensor

NASA Astrophysics Data System (ADS)

Lazarev, Grigory; Bonifer, Stefanie; Engel, Philip; Höhne, Daniel; Notni, Gunther

2017-06-01

We report about the implementation of the liquid crystal on silicon (LCOS) microdisplay with 1920 by 1080 resolution and 720 Hz frame rate. The driving solution is FPGA-based. The input signal is converted from the ultrahigh-resolution HDMI 2.0 signal into HD frames, which follow with the specified 720 Hz frame rate. Alternatively the signal is generated directly on the FPGA with built-in pattern generator. The display is showing switching times below 1.5 ms for the selected working temperature. The bit depth of the addressed image achieves 8 bit within each frame. The microdisplay is used in the fringe projection-based 3D sensing system, implemented by Fraunhofer IOF.

Smaller Footprint Drilling System for Deep and Hard Rock Environments; Feasibility of Ultra-High-Speed Diamond Drilling

DOE Office of Scientific and Technical Information (OSTI.GOV)

TerraTek, A Schlumberger Company

2008-12-31

The two phase program addresses long-term developments in deep well and hard rock drilling. TerraTek believes that significant improvements in drilling deep hard rock will be obtained by applying ultra-high rotational speeds (greater than 10,000 rpm). The work includes a feasibility of concept research effort aimed at development that will ultimately result in the ability to reliably drill 'faster and deeper' possibly with smaller, more mobile rigs. The principle focus is on demonstration testing of diamond bits rotating at speeds in excess of 10,000 rpm to achieve high rate of penetration (ROP) rock cutting with substantially lower inputs of energymore » and loads. The significance of the 'ultra-high rotary speed drilling system' is the ability to drill into rock at very low weights on bit and possibly lower energy levels. The drilling and coring industry today does not practice this technology. The highest rotary speed systems in oil field and mining drilling and coring today run less than 10,000 rpm - usually well below 5,000 rpm. This document provides the progress through two phases of the program entitled 'Smaller Footprint Drilling System for Deep and Hard Rock Environments: Feasibility of Ultra-High-Speed Diamond Drilling' for the period starting 30 June 2003 and concluding 31 March 2009. The accomplishments of Phases 1 and 2 are summarized as follows: (1) TerraTek reviewed applicable literature and documentation and convened a project kick-off meeting with Industry Advisors in attendance (see Black and Judzis); (2) TerraTek designed and planned Phase I bench scale experiments (See Black and Judzis). Improvements were made to the loading mechanism and the rotational speed monitoring instrumentation. New drill bit designs were developed to provided a more consistent product with consistent performance. A test matrix for the final core bit testing program was completed; (3) TerraTek concluded small-scale cutting performance tests; (4) Analysis of Phase 1 data indicated that there is decreased specific energy as the rotational speed increases; (5) Technology transfer, as part of Phase 1, was accomplished with technical presentations to the industry (see Judzis, Boucher, McCammon, and Black); (6) TerraTek prepared a design concept for the high speed drilling test stand, which was planned around the proposed high speed mud motor concept. Alternative drives for the test stand were explored; a high speed hydraulic motor concept was finally used; (7) The high speed system was modified to accommodate larger drill bits than originally planned; (8) Prototype mud turbine motors and the high speed test stand were used to drive the drill bits at high speed; (9) Three different rock types were used during the testing: Sierra White granite, Crab Orchard sandstone, and Colton sandstone. The drill bits used included diamond impregnated bits, a polycrystalline diamond compact (PDC) bit, a thermally stable PDC (TSP) bit, and a hybrid TSP and natural diamond bit; and (10) The drill bits were run at rotary speeds up to 5500 rpm and weight on bit (WOB) to 8000 lbf. During Phase 2, the ROP as measured in depth of cut per bit revolution generally increased with increased WOB. The performance was mixed with increased rotary speed, with the depth cut with the impregnated drill bit generally increasing and the TSP and hybrid TSP drill bits generally decreasing. The ROP in ft/hr generally increased with all bits with increased WOB and rotary speed. The mechanical specific energy generally improved (decreased) with increased WOB and was mixed with increased rotary speed.« less

On the Search for Retrotransposons: Alternative Protocols to Obtain Sequences to Learn Profile Hidden Markov Models.

PubMed

Fischer, Carlos N; Campos, Victor De A; Barella, Victor H

2018-05-01

Profile hidden Markov models (pHMMs) have been used to search for transposable elements (TEs) in genomes. For the learning of pHMMs aimed to search for TEs of the retrotransposon class, the conventional protocol is to use the whole internal nucleotide portions of these elements as representative sequences. To further explore the potential of pHMMs in such a search, we propose five alternative ways to obtain the sets of representative sequences of TEs other than the conventional protocol. In this study, we are interested in Bel-PAO, Copia, Gypsy, and DIRS superfamilies from the retrotransposon class. We compared the pHMMs of all six protocols. The test results show that, for each TE superfamily, the pHMMs of at least two of the proposed protocols performed better than the conventional one and that the number of correct predictions provided by the latter can be improved by considering together the results of one or more of the alternative protocols.

A special attack on the multiparty quantum secret sharing of secure direct communication using single photons

NASA Astrophysics Data System (ADS)

Qin, Su-Juan; Gao, Fei; Wen, Qiao-Yan; Zhu, Fu-Chen

2008-11-01

The security of a multiparty quantum secret sharing protocol [L.F. Han, Y.M. Liu, J. Liu, Z.J. Zhang, Opt. Commun. 281 (2008) 2690] is reexamined. It is shown that any one dishonest participant can obtain all the transmitted secret bits by a special attack, where the controlled- (-iσy) gate is employed to invalidate the role of the random phase shift operation. Furthermore, a possible way to resist this attack is discussed.

Bidirectional private key exchange using delay-coupled semiconductor lasers.

PubMed

Porte, Xavier; Soriano, Miguel C; Brunner, Daniel; Fischer, Ingo

2016-06-15

We experimentally demonstrate a key exchange cryptosystem based on the phenomenon of identical chaos synchronization. In our protocol, the private key is symmetrically generated by the two communicating partners. It is built up from the synchronized bits occurring between two current-modulated bidirectionally coupled semiconductor lasers with additional self-feedback. We analyze the security of the exchanged key and discuss the amplification of its privacy. We demonstrate private key generation rates up to 11  Mbit/s over a public channel.

Distributed Topology Organization and Transmission Scheduling in Wireless Ad Hoc Networks

DTIC Science & Technology

2004-01-01

slot consists of two mini -slots that support that support full-duplex transfer–one for master-to-slave transmission and the other from slave-to-master...protocol storage requirement would only be 208 bits in this case. 111 Communication requirements Each half-duplex mini -slot can be used by either a data or...either a data or control packet, eq. (4.2) sets the minimum half-duplex mini -slot size in the system or equivalently, the maximum system period

Chess games: a model for RNA based computation.

PubMed

Cukras, A R; Faulhammer, D; Lipton, R J; Landweber, L F

1999-10-01

Here we develop the theory of RNA computing and a method for solving the 'knight problem' as an instance of a satisfiability (SAT) problem. Using only biological molecules and enzymes as tools, we developed an algorithm for solving the knight problem (3 x 3 chess board) using a 10-bit combinatorial pool and sequential RNase H digestions. The results of preliminary experiments presented here reveal that the protocol recovers far more correct solutions than expected at random, but the persistence of errors still presents the greatest challenge.

Quantum key distribution over an installed multimode optical fiber local area network.

PubMed

Namekata, Naoto; Mori, Shigehiko; Inoue, Shuichiro

2005-12-12

We have investigated the possibility of a multimode fiber link for a quantum channel. Transmission of light in an extremely underfilled mode distribution promises a single-mode-like behavior in the multimode fiber. To demonstrate the performance of the fiber link we performed quantum key distribution, on the basis of the BB84 four-state protocol, over 550 m of an installed multimode optical fiber local area network, and the quantum-bit-error rate of 1.09 percent was achieved.

Design, Implementation, and Operational Methodologies for Sub-arcsecond Attitude Determination, Control, and Stabilization of the Super-pressure Balloon-Borne Imaging Telescope (SuperBIT)

NASA Astrophysics Data System (ADS)

Javier Romualdez, Luis

Scientific balloon-borne instrumentation offers an attractive, competitive, and effective alternative to space-borne missions when considering the overall scope, cost, and development timescale required to design and launch scientific instruments. In particular, the balloon-borne environment provides a near-space regime that is suitable for a number of modern astronomical and cosmological experiments, where the atmospheric interference suffered by ground-based instrumentation is negligible at stratospheric altitudes. This work is centered around the analytical strategies and implementation considerations for the attitude determination and control of SuperBIT, a scientific balloon-borne payload capable of meeting the strict sub-arcsecond pointing and image stability requirements demanded by modern cosmological experiments. Broadly speaking, the designed stability specifications of SuperBIT coupled with its observational efficiency, image quality, and accessibility rivals state-of-the-art astronomical observatories such as the Hubble Space Telescope. To this end, this work presents an end-to-end design methodology for precision pointing balloon-borne payloads such as SuperBIT within an analytical yet implementationally grounded context. Simulation models of SuperBIT are analytically derived to aid in pre-assembly trade-off and case studies that are pertinent to the dynamic balloon-borne environment. From these results, state estimation techniques and control methodologies are extensively developed, leveraging the analytical framework of simulation models and design studies. This pre-assembly design phase is physically validated during assembly, integration, and testing through implementation in real-time hardware and software, which bridges the gap between analytical results and practical application. SuperBIT attitude determination and control is demonstrated throughout two engineering test flights that verify pointing and image stability requirements in flight, where the post-flight results close the overall design loop by suggesting practical improvements to pre-design methodologies. Overall, the analytical and practical results presented in this work, though centered around the SuperBIT project, provide generically useful and implementationally viable methodologies for high precision balloon-borne instrumentation, all of which are validated, justified, and improved both theoretically and practically. As such, the continuing development of SuperBIT, built from the work presented in this thesis, strives to further the potential for scientific balloon-borne astronomy in the near future.

Data Management for Mars Exploration Rovers

NASA Technical Reports Server (NTRS)

Snyder, Joseph F.; Smyth, David E.

2004-01-01

Data Management for the Mars Exploration Rovers (MER) project is a comprehensive system addressing the needs of development, test, and operations phases of the mission. During development of flight software, including the science software, the data management system can be simulated using any POSIX file system. During testing, the on-board file system can be bit compared with files on the ground to verify proper behavior and end-to-end data flows. During mission operations, end-to-end accountability of data products is supported, from science observation concept to data products within the permanent ground repository. Automated and human-in-the-loop ground tools allow decisions regarding retransmitting, re-prioritizing, and deleting data products to be made using higher level information than is available to a protocol-stack approach such as the CCSDS File Delivery Protocol (CFDP).

High speed bus technology development

NASA Astrophysics Data System (ADS)

Modrow, Marlan B.; Hatfield, Donald W.

1989-09-01

The development and demonstration of the High Speed Data Bus system, a 50 Million bits per second (Mbps) local data network intended for avionics applications in advanced military aircraft is described. The Advanced System Avionics (ASA)/PAVE PILLAR program provided the avionics architecture concept and basic requirements. Designs for wire and fiber optic media were produced and hardware demonstrations were performed. An efficient, robust token-passing protocol was developed and partially demonstrated. The requirements specifications, the trade-offs made, and the resulting designs for both a coaxial wire media system and a fiber optics design are examined. Also, the development of a message-oriented media access protocol is described, from requirements definition through analysis, simulation and experimentation. Finally, the testing and demonstrations conducted on the breadboard and brassboard hardware is presented.

A re-evaluation of the use of branched GDGTs as terrestrial biomarkers: Implications for the BIT Index

NASA Astrophysics Data System (ADS)

Smith, Richard W.; Bianchi, Thomas S.; Li, Xinxin

2012-03-01

This study examines estimates of soil organic matter content (%OMsoil) in marine sediments based on the branched/isoprenoid tetraether (BIT) Index, and suggests a new calculation method based on branched GDGT (brGDGT) concentrations. Four sediment cores were collected in 2008 at the 20 m isobath of the Louisiana Continental Shelf. Glycerol dialkyl glycerol tetraether (GDGTs) and cupric oxide (CuO) oxidation products were analyzed down to ˜20 cm depth to examine terrestrially-derived organic matter. BIT Indices ranged from 0.50 to 0.03, and correlated poorly with lignin (mg S, V, and C phenols 10 g-1 sediment; ∑810) and 3,5-dihydroxybenzoic acid (μg 3,5-Bd g-1 sediment; 3,5:g) concentrations, which ranged from 0.01 to 0.87 mg g-1 and 0.00 (below detection limit) to 1.39 μg g-1, respectively. By calculating mass normalized core-lipid branched GDGT (brGDGT) and crenarchaeol mass abundances with the assistance of a surrogate standard, it was shown that overall, large variations in sedimentary crenarchaeol concentrations were responsible for vertical distributions of BIT Indices, due to the relatively smaller range of brGDGT concentrations. brGDGT concentrations produced stronger correlations with terrestrial CuO oxidation products than the BIT Index, which correlated strongly with crenarchaeol concentrations. Variations in the BIT Index may therefore reflect changes in the delivery of marine-derived organic matter to sediments in regions with large seasonal or decadal shifts in productivity, such as stratified continental shelves. An in depth look at conversions of the BIT Index to percent soil organic matter using a binary mixing model with a marine BIT value of 0 and a terrestrial BIT value of 1 (%OMsoil = BIT Index * 100) used in recent literature reveals that this method results in non-linear mixing of marine and terrestrial end-members, and the shape of the mixing line is based on sedimentary crenarchaeol concentrations. An alternative approach is to use sedimentary brGDGT yields as a OMsoil proxy, rather than normalizing them to crenarchaeol. %OMsoil could then be calculated using brGDGT concentrations in a two end-member mixing model as follows:%OMsoil = ([brGDGT]sample * 100)/[brGDGT]soil, where [brGDGT]sample and [brGDGT]soil represent the concentrations of branched GDGTs in the given sediment sample and in the average soil end-member, respectively. However, due to the wide range of brGDGT concentrations found in soils both regionally and globally, assigning a terrestrial end-member may not always be possible. While this method may in some instances also be a misrepresentation of %OMsoil in sediments, both estimation methods should be used with regard to their individual strengths and weaknesses.

Comment on "Particle path through a nested Mach-Zehnder interferometer"

NASA Astrophysics Data System (ADS)

Salih, Hatim

2018-02-01

In a recent paper [Phys. Rev. A 94, 032115 (2016), 10.1103/PhysRevA.94.032115], Griffiths questioned—based on an interesting consistent-histories (CH) argument—the counterfactuality, for one of the bit choices, of the protocol of Salih et al. for communicating without sending physical particles [Phys. Rev. Lett. 110, 170502 (2013), 10.1103/PhysRevLett.110.170502]. Here, we first show that for the Mach-Zehnder version used to explain our protocol, contrary to Griffiths's claim, no family of consistent histories exists where any history has the photon traveling through the communication channel, thus rendering the question of whether the photon was in the communication channel meaningless from a CH viewpoint. We then show that for the actual Michelson-type protocol, there is a consistent-histories family for each cycle that includes histories where the photon travels through the communication channel. We show that the probability of finding the photon in the communication channel at any time is zero—proving complete counterfactuality.

An Application of Functional Analytic Psychotherapy in a Case of Anxiety Panic Disorder without Agoraphobia

ERIC Educational Resources Information Center

Bermudez, Miguel Angel Lopez; Garcia, Rafael Ferro; Calvillo, Manuel

2010-01-01

Traditional methods of diagnosis are of little therapeutic use when diagnostic criteria are based upon topographical rather than functional aspects of behavior. Also, this sentence in the original seemed rather awkward and a bit unclear. In contrast to this, several authors have put forward experience avoidance disorders as an alternative which…

Coherent one-way quantum key distribution

NASA Astrophysics Data System (ADS)

Stucki, Damien; Fasel, Sylvain; Gisin, Nicolas; Thoma, Yann; Zbinden, Hugo

2007-05-01

Quantum Key Distribution (QKD) consists in the exchange of a secrete key between two distant points [1]. Even if quantum key distribution systems exist and commercial systems are reaching the market [2], there are still improvements to be made: simplify the construction of the system; increase the secret key rate. To this end, we present a new protocol for QKD tailored to work with weak coherent pulses and at high bit rates [3]. The advantages of this system are that the setup is experimentally simple and it is tolerant to reduced interference visibility and to photon number splitting attacks, thus resulting in a high efficiency in terms of distilled secret bits per qubit. After having successfully tested the feasibility of the system [3], we are currently developing a fully integrated and automated prototype within the SECOQC project [4]. We present the latest results using the prototype. We also discuss the issue of the photon detection, which still remains the bottleneck for QKD.

Sagnac secret sharing over telecom fiber networks.

PubMed

Bogdanski, Jan; Ahrens, Johan; Bourennane, Mohamed

2009-01-19

We report the first Sagnac quantum secret sharing (in three-and four-party implementations) over 1550 nm single mode fiber (SMF) networks, using a single qubit protocol with phase encoding. Our secret sharing experiment has been based on a single qubit protocol, which has opened the door to practical secret sharing implementation over fiber telecom channels and in free-space. The previous quantum secret sharing proposals were based on multiparticle entangled states, difficult in the practical implementation and not scalable. Our experimental data in the three-party implementation show stable (in regards to birefringence drift) quantum secret sharing transmissions at the total Sagnac transmission loop distances of 55-75 km with the quantum bit error rates (QBER) of 2.3-2.4% for the mean photon number micro?= 0.1 and 1.7-2.1% for micro= 0.3. In the four-party case we have achieved quantum secret sharing transmissions at the total Sagnac transmission loop distances of 45-55 km with the quantum bit error rates (QBER) of 3.0-3.7% for the mean photon number micro= 0.1 and 1.8-3.0% for micro?= 0.3. The stability of quantum transmission has been achieved thanks to our new concept for compensation of SMF birefringence effects in Sagnac, based on a polarization control system and a polarization insensitive phase modulator. The measurement results have showed feasibility of quantum secret sharing over telecom fiber networks in Sagnac configuration, using standard fiber telecom components.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hayashi, A.; Hashimoto, T.; Horibe, M.

In quantum teleportation, neither Alice nor Bob acquires any classical knowledge on teleported states. The teleportation protocol is said to be oblivious to both parties. In remote state preparation (RSP), it is assumed that Alice is given complete classical knowledge on the state that is to be prepared by Bob. Recently, Leung and Shor [e-print quant-ph/0201008] showed that the same amount of classical information as that in teleportation needs to be transmitted in any exact and deterministic RSP protocol that is oblivious to Bob. Assuming that the dimension of subsystems in the prior-entangled state is the same as the dimensionmore » of the input space, we study similar RSP protocols, but not necessarily oblivious to Bob. We show that in this case Bob's quantum operation can be safely assumed to be a unitary transformation. We then derive an equation that is a necessary and sufficient condition for such a protocol to exist. By studying this equation, we show that one-qubit RSP requires two classical bits of communication, which is the same amount as in teleportation, even if the protocol is not assumed oblivious to Bob. For higher dimensions, it is still an open question whether the amount of classical communication can be reduced by abandoning oblivious conditions.« less

Influence of the Distribution of Tag IDs on RFID Memoryless Anti-Collision Protocols.

PubMed

Cmiljanic, Nikola; Landaluce, Hugo; Perallos, Asier; Arjona, Laura

2017-08-17

In recent years, Radio Frequency Identification (RFID) has become very popular. The main feature of this technology is that RFID tags do not require close handling and no line of sight is required between the reader and the tags. RFID is a technology that uses radio frequencies in order to identify tags, which do not need to be positioned accurately relative to the reader. Tags share the communication channel, increasing the likelihood of causing a problem, viz., a message collision. Tree based protocols can resolve these collisions, but require a uniform tag ID distribution. This means they are very dependent of the distribution of the IDs of the tags. Tag IDs are written in the tag and contain a predefined bit string of data. A study of the influence of the tag ID distribution on the protocols' behaviour is proposed here. A new protocol, called the Flexible Query window Tree (FQwT) is presented to estimate the tag ID distribution, taking into consideration the type of distribution. The aim is to create a flexible anti-collision protocol in order to identify a set of tags that constitute an ID distribution. As a result, the reader classifies tags into groups determined by using a distribution estimator. Simulations show that the FQwT protocol contributes to significant reductions in identification time and energy consumption regardless of the type of ID distribution.

A program of telementoring in laparoscopic bariatric surgery.

PubMed

Fuertes-Guiró, Fernando; Vitali-Erion, Enrique; Rodriguez-Franco, Amalia

2016-01-01

This study proposes a system for teaching and surgical support with the benefits of online Information and Communications Technology (ITC) -based telementoring for laparoscopic bariatric surgery (LBS). A system of telementoring was established between a university center and two community hospitals. Telementoring was performed via internet protocol using a direct point-to-point connection, ASDL 1.2 Mbps, time delay 150 ms, 256-bit advanced encryption standard (AES). In the period of time selected, all interventions for LBS in both hospitals were included. When patients agree with telementoring, data outcomes (operating time, hospital stay, conversion to open surgery and complications) were collected. The rest of these interventions were recorded. Thirty-six patients underwent elective LBS, 20 of whom were referred and accepted for telementoring. Patients selected without telementoring took longer: 200 (46) min vs 139 (33) min, p < 0.01. There were two conversions in non-mentored groups. The hospital stay was 4.6 (0.5) days for telementored interventions and 6.7 (0.5) days without mentoring (p < 0.01). Four patients (12,5%) in non-mentored groups suffered minor complications. This program supports the safety and feasibility of telementoring in LBS. Telementoring is an alternative in community hospitals because it can improve the quality of advanced procedures of laparoscopic surgery.

Components of an Anticancer Diet: Dietary Recommendations, Restrictions and Supplements of the Bill Henderson Protocol

PubMed Central

Mannion, Cynthia; Page, Stacey; Bell, Laurie Heilman; Verhoef, Marja

2010-01-01

The use of complementary and alternative medicines including dietary supplements, herbals and special diets to prevent or treat disease continues to be popular. The following paper provides a description of an alternative dietary approach to the self-management and treatment of cancer, the Bill Henderson Protocol (BHP). This diet encourages daily intake of raw foods, a combination of cottage cheese and flaxseed oil and a number of supplements. Some foods and food groups are restricted (e.g., gluten, meat, dairy). Early background theory that contributed to the protocol’s development is presented as is a summary of relevant evidence concerning the anti-cancer fighting properties of the individual components. Supplement intake is considered in relation to daily recommended intakes. Challenges and risks to protocol adherence are discussed. As with many complementary and alternative interventions, clear evidence of this dietary protocol’s safety and efficacy is lacking. Consumers of this protocol may require guidance on the ability of this protocol to meet their individual nutritional needs. PMID:22254073

Controlled Bidirectional Quantum Secure Direct Communication

PubMed Central

Chou, Yao-Hsin; Lin, Yu-Ting; Zeng, Guo-Jyun; Lin, Fang-Jhu; Chen, Chi-Yuan

2014-01-01

We propose a novel protocol for controlled bidirectional quantum secure communication based on a nonlocal swap gate scheme. Our proposed protocol would be applied to a system in which a controller (supervisor/Charlie) controls the bidirectional communication with quantum information or secret messages between legitimate users (Alice and Bob). In this system, the legitimate users must obtain permission from the controller in order to exchange their respective quantum information or secret messages simultaneously; the controller is unable to obtain any quantum information or secret messages from the decoding process. Moreover, the presence of the controller also avoids the problem of one legitimate user receiving the quantum information or secret message before the other, and then refusing to help the other user decode the quantum information or secret message. Our proposed protocol is aimed at protecting against external and participant attacks on such a system, and the cost of transmitting quantum bits using our protocol is less than that achieved in other studies. Based on the nonlocal swap gate scheme, the legitimate users exchange their quantum information or secret messages without transmission in a public channel, thus protecting against eavesdroppers stealing the secret messages. PMID:25006596

ALT-114 and ALT-118 Alternative Approaches to NIST-Traceable Reference Gases

EPA Science Inventory

In 2016, US EPA approved two separate alternatives (ALT 114 and ALT 118) for the preparation and certification of Hydrogen Chloride (HCl) and Mercury (Hg) cylinder reference gas standards that can serve as EPA Protocol gases where EPA Protocol are required, but unavailable. The a...

Quantum repeaters using continuous-variable teleportation

NASA Astrophysics Data System (ADS)

Dias, Josephine; Ralph, T. C.

2017-02-01

Quantum optical states are fragile and can become corrupted when passed through a lossy communication channel. Unlike for classical signals, optical amplifiers cannot be used to recover quantum signals. Quantum repeaters have been proposed as a way of reducing errors and hence increasing the range of quantum communications. Current protocols target specific discrete encodings, for example quantum bits encoded on the polarization of single photons. We introduce a more general approach that can reduce the effect of loss on any quantum optical encoding, including those based on continuous variables such as the field amplitudes. We show that in principle the protocol incurs a resource cost that scales polynomially with distance. We analyze the simplest implementation and find that while its range is limited it can still achieve useful improvements in the distance over which quantum entanglement of field amplitudes can be distributed.

Improving the efficiency of quantum hash function by dense coding of coin operators in discrete-time quantum walk

NASA Astrophysics Data System (ADS)

Yang, YuGuang; Zhang, YuChen; Xu, Gang; Chen, XiuBo; Zhou, Yi-Hua; Shi, WeiMin

2018-03-01

Li et al. first proposed a quantum hash function (QHF) in a quantum-walk architecture. In their scheme, two two-particle interactions, i.e., I interaction and π-phase interaction are introduced and the choice of I or π-phase interactions at each iteration depends on a message bit. In this paper, we propose an efficient QHF by dense coding of coin operators in discrete-time quantum walk. Compared with existing QHFs, our protocol has the following advantages: the efficiency of the QHF can be doubled and even more; only one particle is enough and two-particle interactions are unnecessary so that quantum resources are saved. It is a clue to apply the dense coding technique to quantum cryptographic protocols, especially to the applications with restricted quantum resources.

Towards a Quantum Memory assisted MDI-QKD node

NASA Astrophysics Data System (ADS)

Namazi, Mehdi; Vallone, Giuseppe; Jordaan, Bertus; Goham, Connor; Shahrokhshahi, Reihaneh; Villoresi, Paolo; Figueroa, Eden

2017-04-01

The creation of large quantum network that permits the communication of quantum states and the secure distribution of cryptographic keys requires multiple operational quantum memories. In this work we present our progress towards building a prototypical quantum network that performs the memory-assisted measurement device independent QKD protocol. Currently our network combines the quantum part of the BB84 protocol with room-temperature quantum memory operation, while still maintaining relevant quantum bit error rates for single-photon level operation. We will also discuss our efforts to use a network of two room temperature quantum memories, receiving, storing and transforming randomly polarized photons in order to realize Bell state measurements. The work was supported by the US-Navy Office of Naval Research, Grant Number N00141410801, the National Science Foundation, Grant Number PHY-1404398 and the Simons Foundation, Grant Number SBF241180.

An Evaluation of Alternative Designs for a Grid Information Service

NASA Technical Reports Server (NTRS)

Smith, Warren; Waheed, Abdul; Meyers, David; Yan, Jerry; Kwak, Dochan (Technical Monitor)

2001-01-01

The Globus information service wasn't working well. There were many updates of data from Globus daemons which saturated the single server and users couldn't retrieve information. We created a second server for NASA and Alliance. Things were great on that server, but a bit slow on the other server. We needed to know exactly how the information service was being used. What were the best servers and configurations? This viewgraph presentation gives an overview of the evaluation of alternative designs for a Grid Information Service. Details are given on the workload characterization, methodology used, and the performance evaluation.

The compression–error trade-off for large gridded data sets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silver, Jeremy D.; Zender, Charles S.

The netCDF-4 format is widely used for large gridded scientific data sets and includes several compression methods: lossy linear scaling and the non-lossy deflate and shuffle algorithms. Many multidimensional geoscientific data sets exhibit considerable variation over one or several spatial dimensions (e.g., vertically) with less variation in the remaining dimensions (e.g., horizontally). On such data sets, linear scaling with a single pair of scale and offset parameters often entails considerable loss of precision. We introduce an alternative compression method called "layer-packing" that simultaneously exploits lossy linear scaling and lossless compression. Layer-packing stores arrays (instead of a scalar pair) of scalemore » and offset parameters. An implementation of this method is compared with lossless compression, storing data at fixed relative precision (bit-grooming) and scalar linear packing in terms of compression ratio, accuracy and speed. When viewed as a trade-off between compression and error, layer-packing yields similar results to bit-grooming (storing between 3 and 4 significant figures). Bit-grooming and layer-packing offer significantly better control of precision than scalar linear packing. Relative performance, in terms of compression and errors, of bit-groomed and layer-packed data were strongly predicted by the entropy of the exponent array, and lossless compression was well predicted by entropy of the original data array. Layer-packed data files must be "unpacked" to be readily usable. The compression and precision characteristics make layer-packing a competitive archive format for many scientific data sets.« less

The compression–error trade-off for large gridded data sets

DOE PAGES

Silver, Jeremy D.; Zender, Charles S.

2017-01-27

The netCDF-4 format is widely used for large gridded scientific data sets and includes several compression methods: lossy linear scaling and the non-lossy deflate and shuffle algorithms. Many multidimensional geoscientific data sets exhibit considerable variation over one or several spatial dimensions (e.g., vertically) with less variation in the remaining dimensions (e.g., horizontally). On such data sets, linear scaling with a single pair of scale and offset parameters often entails considerable loss of precision. We introduce an alternative compression method called "layer-packing" that simultaneously exploits lossy linear scaling and lossless compression. Layer-packing stores arrays (instead of a scalar pair) of scalemore » and offset parameters. An implementation of this method is compared with lossless compression, storing data at fixed relative precision (bit-grooming) and scalar linear packing in terms of compression ratio, accuracy and speed. When viewed as a trade-off between compression and error, layer-packing yields similar results to bit-grooming (storing between 3 and 4 significant figures). Bit-grooming and layer-packing offer significantly better control of precision than scalar linear packing. Relative performance, in terms of compression and errors, of bit-groomed and layer-packed data were strongly predicted by the entropy of the exponent array, and lossless compression was well predicted by entropy of the original data array. Layer-packed data files must be "unpacked" to be readily usable. The compression and precision characteristics make layer-packing a competitive archive format for many scientific data sets.« less

Continued Development of a Universal Network Interface Device Using the Intel 8086 and 8089 16-Bit Microprocessors.

DTIC Science & Technology

1983-12-15

7 "AD-RI38 iig CONTINUED DE VELOPMlENT OF UNIERSL NETWORK INTERFCE 1/2 DEVICE USING THE I..(U) AIR FORCE INST OF TECHD-F13 ill WRIGHT PATTERSON AFB...Protocols," IEEE Transactions on Communications, COM-28(4):433-44 (April 1980). 3. Borgsmiller, Michael. "The Serial Communications Interface Board...Interconnections," IEEE Transactions on Communications, COM-28(4): 425- 432, (April 1980). 4. I L Appendix A UNID II Data Flow Diagrams (Ref 10:26-34) This

Design, Development, and Demonstration of a Prognostic and Diagnostics Health Monitoring System for the CROWS Platform

DTIC Science & Technology

2010-06-01

automatically appended onto the data packet by the CC2420 transceiver. The frame control field (FCF), data sequence number, and frame check sequence (FCS...by the CC2420 over the MAC protocol data unit (MPDU), i.e., the length field is not part of the FCS. This field is automatically generated and...verified by the CC2420 hardware when the AUTOCRC control bit is set in the MODEMCTRL0 control register’s field . If the FCS check indicates that a data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nielsen, Erik; Blume-Kohout, Robin; Rudinger, Kenneth

PyGSTi is an implementation of Gate Set Tomography in the python programming language. Gate Set Tomography (GST) is a theory and protocol for simultaneously estimating the state preparation, gate operations, and measurement effects of a physical system of one or many quantum bits (qubits). These estimates are based entirely on the statistics of experimental measurements, and their interpretation and analysis can provide a detailed understanding of the types of errors/imperfections in the physical system. In this way, GST provides not only a means of certifying the "goodness" of qubits but also a means of debugging (i.e. improving) them.

Some conservative estimates in quantum cryptography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Molotkov, S. N.

2006-08-15

Relationship is established between the security of the BB84 quantum key distribution protocol and the forward and converse coding theorems for quantum communication channels. The upper bound Q{sub c} {approx} 11% on the bit error rate compatible with secure key distribution is determined by solving the transcendental equation H(Q{sub c})=C-bar({rho})/2, where {rho} is the density matrix of the input ensemble, C-bar({rho}) is the classical capacity of a noiseless quantum channel, and H(Q) is the capacity of a classical binary symmetric channel with error rate Q.

Alternating-Offers Protocol for Multi-issue Bilateral Negotiation in Semantic-Enabled Marketplaces

NASA Astrophysics Data System (ADS)

Ragone, Azzurra; di Noia, Tommaso; di Sciascio, Eugenio; Donini, Francesco M.

We present a semantic-based approach to multi-issue bilateral negotiation for e-commerce. We use Description Logics to model advertisements, and relations among issues as axioms in a TBox. We then introduce a logic-based alternating-offers protocol, able to handle conflicting information, that merges non-standard reasoning services in Description Logics with utility thoery to find the most suitable agreements. We illustrate and motivate the theoretical framework, the logical language, and the negotiation protocol.

Learning to assign binary weights to binary descriptor

NASA Astrophysics Data System (ADS)

Huang, Zhoudi; Wei, Zhenzhong; Zhang, Guangjun

2016-10-01

Constructing robust binary local feature descriptors are receiving increasing interest due to their binary nature, which can enable fast processing while requiring significantly less memory than their floating-point competitors. To bridge the performance gap between the binary and floating-point descriptors without increasing the computational cost of computing and matching, optimal binary weights are learning to assign to binary descriptor for considering each bit might contribute differently to the distinctiveness and robustness. Technically, a large-scale regularized optimization method is applied to learn float weights for each bit of the binary descriptor. Furthermore, binary approximation for the float weights is performed by utilizing an efficient alternatively greedy strategy, which can significantly improve the discriminative power while preserve fast matching advantage. Extensive experimental results on two challenging datasets (Brown dataset and Oxford dataset) demonstrate the effectiveness and efficiency of the proposed method.

Anisotropic transmissive coding metamaterials based on dispersion modulation of spoof surface plasmon polaritons

NASA Astrophysics Data System (ADS)

Pang, Yongqiang; Li, Yongfeng; Zhang, Jieqiu; Chen, Hongya; Xu, Zhuo; Qu, Shaobo

2018-06-01

Anisotropic transmissive coding metamaterials (CMMs) have been designed and demonstrated in this work. High-efficiency transmission with the amplitudes close to unity is achieved by ultrathin metallic tapered blade structures, on which incident waves can be highly coupled into spoof surface plasmon polaritons (SSPPs). The transmission phase can be therefore manipulated with much freedom by designing the dispersion of the SSPPs. These tapered blade structures are designed as the anisotropic unit cells of the CMMs. Two 1-bit anisotropic CMMs with different coding sequences were first designed and simulated, and then a 2-bit anisotropic CMM was designed and measured experimentally. The measured results agree well with the simulations. It is expected that this work provides an alternative method for designing the transmissive CMMs, and may find potential applications in the beam forming technique.

Narb-Based Analysis of Tweets Related to United Airlines Controversy: Learning beyond the Media

ERIC Educational Resources Information Center

Mitra, Ananda

2017-01-01

The use of narrative bits--narbs--has been discussed as an alternative means of looking at opinions of those who are producing narbs, for instance, in the form of tweets. The American carrier, United Airlines, came under media attention in April 2016 when a passenger was forcibly removed from a flight. This resulted in a spike in tweets around the…

Evaluation of BLAST-based edge-weighting metrics used for homology inference with the Markov Clustering algorithm.

PubMed

Gibbons, Theodore R; Mount, Stephen M; Cooper, Endymion D; Delwiche, Charles F

2015-07-10

Clustering protein sequences according to inferred homology is a fundamental step in the analysis of many large data sets. Since the publication of the Markov Clustering (MCL) algorithm in 2002, it has been the centerpiece of several popular applications. Each of these approaches generates an undirected graph that represents sequences as nodes connected to each other by edges weighted with a BLAST-based metric. MCL is then used to infer clusters of homologous proteins by analyzing these graphs. The various approaches differ only by how they weight the edges, yet there has been very little direct examination of the relative performance of alternative edge-weighting metrics. This study compares the performance of four BLAST-based edge-weighting metrics: the bit score, bit score ratio (BSR), bit score over anchored length (BAL), and negative common log of the expectation value (NLE). Performance is tested using the Extended CEGMA KOGs (ECK) database, which we introduce here. All metrics performed similarly when analyzing full-length sequences, but dramatic differences emerged as progressively larger fractions of the test sequences were split into fragments. The BSR and BAL successfully rescued subsets of clusters by strengthening certain types of alignments between fragmented sequences, but also shifted the largest correct scores down near the range of scores generated from spurious alignments. This penalty outweighed the benefits in most test cases, and was greatly exacerbated by increasing the MCL inflation parameter, making these metrics less robust than the bit score or the more popular NLE. Notably, the bit score performed as well or better than the other three metrics in all scenarios. The results provide a strong case for use of the bit score, which appears to offer equivalent or superior performance to the more popular NLE. The insight that MCL-based clustering methods can be improved using a more tractable edge-weighting metric will greatly simplify future implementations. We demonstrate this with our own minimalist Python implementation: Porthos, which uses only standard libraries and can process a graph with 25 m + edges connecting the 60 k + KOG sequences in half a minute using less than half a gigabyte of memory.

Remote Observing with the Keck Telescope Using the ACTS Satellite

NASA Technical Reports Server (NTRS)

Cohen, Judy; Shopbell, Patrick; Bergman, Larry

1998-01-01

As a technical demonstration project for the NASA Advanced Communications Technology Satellite (ACTS), we have implemented remote observing on the 10-meter Keck II telescope on Mauna Kea in Hawaii from the California Institute of Technology campus in Pasadena. The data connection consists of optical fiber networks in Hawaii and California, connecting the end-points to high data rate (HDR) ACTS satellite antennae at JPL in Pasadena and at the Tripler Army Medical Center in Honolulu. The terrestrial fiber networks run the asynchronous transfer mode (ATM) protocol at DS-3 (45 Mbit/sec) speeds, providing ample bandwidth to enable remote observing with a software environment identical to that used for on-site observing in Hawaii. This experiment has explored the data requirements of remote observing with a modern research telescope and large-format detector arrays. While the maximum burst data rates are lower than those required for many other applications (e.g., HDTV), the network reliability and data integrity requirements are critical. As we show in this report, the former issue particularly may be the greatest challenge for satellite networks for this class of application. We have also experimented with the portability of standard TCP/IP applications to satellite networks, demonstrating the need for alternative TCP congestion algorithms and minimization of bit error rates (BER). Reliability issues aside, we have demonstrated that true remote observing over high-speed networks provides several important advantages over standard observing paradigms. Technical advantages of the high-speed network access include more rapid download of data to a user's home institution and the opportunity for alternative communication facilities between members of an observing team, such as audio- and videoconferencing.

A gossip based information fusion protocol for distributed frequent itemset mining

NASA Astrophysics Data System (ADS)

Sohrabi, Mohammad Karim

2018-07-01

The computational complexity, huge memory space requirement, and time-consuming nature of frequent pattern mining process are the most important motivations for distribution and parallelization of this mining process. On the other hand, the emergence of distributed computational and operational environments, which causes the production and maintenance of data on different distributed data sources, makes the parallelization and distribution of the knowledge discovery process inevitable. In this paper, a gossip based distributed itemset mining (GDIM) algorithm is proposed to extract frequent itemsets, which are special types of frequent patterns, in a wireless sensor network environment. In this algorithm, local frequent itemsets of each sensor are extracted using a bit-wise horizontal approach (LHPM) from the nodes which are clustered using a leach-based protocol. Heads of clusters exploit a gossip based protocol in order to communicate each other to find the patterns which their global support is equal to or more than the specified support threshold. Experimental results show that the proposed algorithm outperforms the best existing gossip based algorithm in term of execution time.

Measurement device-independent quantum dialogue

NASA Astrophysics Data System (ADS)

Maitra, Arpita

2017-12-01

Very recently, the experimental demonstration of quantum secure direct communication (QSDC) with state-of-the-art atomic quantum memory has been reported (Zhang et al. in Phys Rev Lett 118:220501, 2017). Quantum dialogue (QD) falls under QSDC where the secrete messages are communicated simultaneously between two legitimate parties. The successful experimental demonstration of QSDC opens up the possibilities for practical implementation of QD protocols. Thus, it is necessary to analyze the practical security issues of QD protocols for future implementation. Since the very first proposal for QD by Nguyen (Phys Lett A 328:6-10, 2004), a large number of variants and extensions have been presented till date. However, all of those leak half of the secret bits to the adversary through classical communications of the measurement results. In this direction, motivated by the idea of Lo et al. (Phys Rev Lett 108:130503, 2012), we propose a measurement device-independent quantum dialogue scheme which is resistant to such information leakage as well as side-channel attacks. In the proposed protocol, Alice and Bob, two legitimate parties, are allowed to prepare the states only. The states are measured by an untrusted third party who may himself behave as an adversary. We show that our protocol is secure under this adversarial model. The current protocol does not require any quantum memory, and thus, it is inherently robust against memory attacks. Such robustness might not be guaranteed in the QSDC protocol with quantum memory (Zhang et al. 2017).

Security of two quantum cryptography protocols using the same four qubit states

DOE Office of Scientific and Technical Information (OSTI.GOV)

Branciard, Cyril; Ecole Nationale Superieure des Telecommunications, 46, rue Barrault, 75013 Paris; Gisin, Nicolas

2005-09-15

The first quantum cryptography protocol, proposed by Bennett and Brassard in 1984 (BB84), has been widely studied in recent years. This protocol uses four states (more precisely, two complementary bases) for the encoding of the classical bit. Recently, it has been noticed that by using the same four states, but a different encoding of information, one can define a protocol which is more robust in practical implementations, specifically when attenuated laser pulses are used instead of single-photon sources [V. Scarani et al., Phys. Rev. Lett. 92, 057901 (2004), referred to as the SARG04 protocol]. We present a detailed study ofmore » SARG04 in two different regimes. In the first part, we consider an implementation with a single-photon source: we derive bounds on the error rate Q for security against all possible attacks by the eavesdropper. The lower and the upper bound obtained for SARG04 (Q < or approx. 10.95% and Q > or approx. 14.9%, respectively) are close to those obtained for BB84 (Q < or approx. 12.4% and Q > or approx. 14.6%, respectively). In the second part, we consider a realistic source consisting of an attenuated laser and improve on previous analysis by allowing Alice to optimize the mean number of photons as a function of the distance. The SARG04 protocol is found to perform better than BB84, both in secret-key rate and in maximal achievable distance, for a wide class of Eve's attacks.« less

Recommended Methodology for Inter-Service/Agency Automated Message Processing Exchange (I-S/A AMPE). Cost and Schedule Analysis of Security Alternatives.

DTIC Science & Technology

1982-02-23

segregate the computer and storage from the outside world 2. Administrative security to control access to secure computer facilities 3. Network security to...Classification Alternative A- 8 NETWORK KG GENSER DSSCS AMPE TERMINALS TP No. 022-4668-A Figure A-2. Dedicated Switching Architecture Alternative A- 9...communications protocol with the network and GENSER message transmission to the - I-S/A AMPE processor. 7. DSSCS TPU - Handles communications protocol with

Influence of the Distribution of Tag IDs on RFID Memoryless Anti-Collision Protocols

PubMed Central

Cmiljanic, Nikola; Landaluce, Hugo; Perallos, Asier; Arjona, Laura

2017-01-01

In recent years, Radio Frequency Identification (RFID) has become very popular. The main feature of this technology is that RFID tags do not require close handling and no line of sight is required between the reader and the tags. RFID is a technology that uses radio frequencies in order to identify tags, which do not need to be positioned accurately relative to the reader. Tags share the communication channel, increasing the likelihood of causing a problem, viz., a message collision. Tree based protocols can resolve these collisions, but require a uniform tag ID distribution. This means they are very dependent of the distribution of the IDs of the tags. Tag IDs are written in the tag and contain a predefined bit string of data. A study of the influence of the tag ID distribution on the protocols’ behaviour is proposed here. A new protocol, called the Flexible Query window Tree (FQwT) is presented to estimate the tag ID distribution, taking into consideration the type of distribution. The aim is to create a flexible anti-collision protocol in order to identify a set of tags that constitute an ID distribution. As a result, the reader classifies tags into groups determined by using a distribution estimator. Simulations show that the FQwT protocol contributes to significant reductions in identification time and energy consumption regardless of the type of ID distribution. PMID:28817070

Flexible Peripheral Component Interconnect Input/Output Card

NASA Technical Reports Server (NTRS)

Bigelow, Kirk K.; Jerry, Albert L.; Baricio, Alisha G.; Cummings, Jon K.

2010-01-01

The Flexible Peripheral Component Interconnect (PCI) Input/Output (I/O) Card is an innovative circuit board that provides functionality to interface between a variety of devices. It supports user-defined interrupts for interface synchronization, tracks system faults and failures, and includes checksum and parity evaluation of interface data. The card supports up to 16 channels of high-speed, half-duplex, low-voltage digital signaling (LVDS) serial data, and can interface combinations of serial and parallel devices. Placement of a processor within the field programmable gate array (FPGA) controls an embedded application with links to host memory over its PCI bus. The FPGA also provides protocol stacking and quick digital signal processor (DSP) functions to improve host performance. Hardware timers, counters, state machines, and other glue logic support interface communications. The Flexible PCI I/O Card provides an interface for a variety of dissimilar computer systems, featuring direct memory access functionality. The card has the following attributes: 8/16/32-bit, 33-MHz PCI r2.2 compliance, Configurable for universal 3.3V/5V interface slots, PCI interface based on PLX Technology's PCI9056 ASIC, General-use 512K 16 SDRAM memory, General-use 1M 16 Flash memory, FPGA with 3K to 56K logical cells with embedded 27K to 198K bits RAM, I/O interface: 32-channel LVDS differential transceivers configured in eight, 4-bit banks; signaling rates to 200 MHz per channel, Common SCSI-3, 68-pin interface connector.

Transitioning to Low-GWP Alternatives in Aerosols

EPA Pesticide Factsheets

This fact sheet provides information on low-GWP alternatives for non-medical commercial aerosols, relevant to the Montreal Protocol. It discusses HFC alternatives, market trends, and challenges to market entry for alternatives and potential solutions.

Quantum computing on encrypted data

NASA Astrophysics Data System (ADS)

Fisher, K. A. G.; Broadbent, A.; Shalm, L. K.; Yan, Z.; Lavoie, J.; Prevedel, R.; Jennewein, T.; Resch, K. J.

2014-01-01

The ability to perform computations on encrypted data is a powerful tool for protecting privacy. Recently, protocols to achieve this on classical computing systems have been found. Here, we present an efficient solution to the quantum analogue of this problem that enables arbitrary quantum computations to be carried out on encrypted quantum data. We prove that an untrusted server can implement a universal set of quantum gates on encrypted quantum bits (qubits) without learning any information about the inputs, while the client, knowing the decryption key, can easily decrypt the results of the computation. We experimentally demonstrate, using single photons and linear optics, the encryption and decryption scheme on a set of gates sufficient for arbitrary quantum computations. As our protocol requires few extra resources compared with other schemes it can be easily incorporated into the design of future quantum servers. These results will play a key role in enabling the development of secure distributed quantum systems.

Public-key quantum digital signature scheme with one-time pad private-key

NASA Astrophysics Data System (ADS)

Chen, Feng-Lin; Liu, Wan-Fang; Chen, Su-Gen; Wang, Zhi-Hua

2018-01-01

A quantum digital signature scheme is firstly proposed based on public-key quantum cryptosystem. In the scheme, the verification public-key is derived from the signer's identity information (such as e-mail) on the foundation of identity-based encryption, and the signature private-key is generated by one-time pad (OTP) protocol. The public-key and private-key pair belongs to classical bits, but the signature cipher belongs to quantum qubits. After the signer announces the public-key and generates the final quantum signature, each verifier can verify publicly whether the signature is valid or not with the public-key and quantum digital digest. Analysis results show that the proposed scheme satisfies non-repudiation and unforgeability. Information-theoretic security of the scheme is ensured by quantum indistinguishability mechanics and OTP protocol. Based on the public-key cryptosystem, the proposed scheme is easier to be realized compared with other quantum signature schemes under current technical conditions.

Quantum computing on encrypted data.

PubMed

Fisher, K A G; Broadbent, A; Shalm, L K; Yan, Z; Lavoie, J; Prevedel, R; Jennewein, T; Resch, K J

2014-01-01

The ability to perform computations on encrypted data is a powerful tool for protecting privacy. Recently, protocols to achieve this on classical computing systems have been found. Here, we present an efficient solution to the quantum analogue of this problem that enables arbitrary quantum computations to be carried out on encrypted quantum data. We prove that an untrusted server can implement a universal set of quantum gates on encrypted quantum bits (qubits) without learning any information about the inputs, while the client, knowing the decryption key, can easily decrypt the results of the computation. We experimentally demonstrate, using single photons and linear optics, the encryption and decryption scheme on a set of gates sufficient for arbitrary quantum computations. As our protocol requires few extra resources compared with other schemes it can be easily incorporated into the design of future quantum servers. These results will play a key role in enabling the development of secure distributed quantum systems.

Direct measurement of weakly nonequilibrium system entropy is consistent with Gibbs–Shannon form

PubMed Central

2017-01-01

Stochastic thermodynamics extends classical thermodynamics to small systems in contact with one or more heat baths. It can account for the effects of thermal fluctuations and describe systems far from thermodynamic equilibrium. A basic assumption is that the expression for Shannon entropy is the appropriate description for the entropy of a nonequilibrium system in such a setting. Here we measure experimentally this function in a system that is in local but not global equilibrium. Our system is a micron-scale colloidal particle in water, in a virtual double-well potential created by a feedback trap. We measure the work to erase a fraction of a bit of information and show that it is bounded by the Shannon entropy for a two-state system. Further, by measuring directly the reversibility of slow protocols, we can distinguish unambiguously between protocols that can and cannot reach the expected thermodynamic bounds. PMID:29073017

Intraosseous Heat Generation During Osteotomy Performed Freehand and Through Template With an Integrated Metal Guide Sleeve: An In Vitro Study.

PubMed

Barrak, Ibrahim; Joób-Fancsaly, Árpád; Braunitzer, Gábor; Varga, Endre; Boa, Kristóf; Piffkó, József

2018-06-01

To investigate drill wear and consequent intraosseous temperature elevation during freehand and guided bone drilling, with attention to the effect of metal-on-metal contact during guided drilling. Osteotomies were performed on bovine ribs, with 2.0 mm diameter stainless steel drill bits of the SMART Guide System, under 3 sterilization protocols, at 800, 1200, 1500, and 2000 rpm. Sterilization was performed after every 3 drilling. Temperature was measured after every 30 drilling. The studied contributing factors had a cumulative effect, and each contributed significantly to temperature elevation. Whether guide use led to a near-necrotic (47°C) temperature increment depended largely on the applied sterilization protocol. The metal sleeve is a significant contributing factor to heat generation during guided osteotomy, but its effect can be offset by keeping the other studied factors under control.

GLOBECOM '84 - Global Telecommunications Conference, Atlanta, GA, November 26-29, 1984, Conference Record. Volume 3

NASA Astrophysics Data System (ADS)

Attention is given to aspects of quality assurance methodologies in development life cycles, optical intercity transmission systems, multiaccess protocols, system and technology aspects in the case of regional/domestic satellites, advances in SSB-AM radio transmission over terrestrial and satellite network, and development environments for telecommunications systems. Other subjects studied are concerned with business communication networks for voice and data, VLSI in local network and communication protocol, product evaluation and support, an update regarding Videotex, topics in communication theory, topics in radio propagation, a status report regarding societal effects of technology in the workplace, digital image processing, and adaptive signal processing for communications. The management of the reliability function in the development process is considered along with Giga-bit technologies for long distance large capacity optical transmission equipment. The application of gallium arsenide analog and digital integrated circuits for high-speed fiber optical communications, and a simple algorithm for image data coding.

Phase-encoded measurement device independent quantum key distribution without a shared reference frame

NASA Astrophysics Data System (ADS)

Zhuo-Dan, Zhu; Shang-Hong, Zhao; Chen, Dong; Ying, Sun

2018-07-01

In this paper, a phase-encoded measurement device independent quantum key distribution (MDI-QKD) protocol without a shared reference frame is presented, which can generate secure keys between two parties while the quantum channel or interferometer introduces an unknown and slowly time-varying phase. The corresponding secret key rate and single photons bit error rate is analysed, respectively, with single photons source (SPS) and weak coherent source (WCS), taking finite-key analysis into account. The numerical simulations show that the modified phase-encoded MDI-QKD protocol has apparent superiority both in maximal secure transmission distance and key generation rate while possessing the improved robustness and practical security in the high-speed case. Moreover, the rejection of the frame-calibrating part will intrinsically reduce the consumption of resources as well as the potential security flaws of practical MDI-QKD systems.

Counterfactual quantum cryptography based on weak coherent states

NASA Astrophysics Data System (ADS)

Yin, Zhen-Qiang; Li, Hong-Wei; Yao, Yao; Zhang, Chun-Mei; Wang, Shuang; Chen, Wei; Guo, Guang-Can; Han, Zheng-Fu

2012-08-01

In the “counterfactual quantum cryptography” scheme [T.-G. Noh, Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.103.230501 103, 230501 (2009)], two legitimate distant peers may share secret-key bits even when the information carriers do not travel in the quantum channel. The security of this protocol with an ideal single-photon source has been proved by Yin [Z.-Q. Yin, H. W. Li, W. Chen, Z. F. Han, and G. C. Guo, Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.82.042335 82, 042335 (2010)]. In this paper, we prove the security of the counterfactual-quantum-cryptography scheme based on a commonly used weak-coherent-laser source by considering a general collective attack. The basic assumption of this proof is that the efficiency and dark-counting rate of a single-photon detector are consistent for any n-photon Fock states. Then through randomizing the phases of the encoding weak coherent states, Eve's ancilla will be transformed into a classical mixture. Finally, the lower bound of the secret-key-bit rate and a performance analysis for the practical implementation are both given.

Solution-Processed Carbon Nanotube True Random Number Generator.

PubMed

Gaviria Rojas, William A; McMorrow, Julian J; Geier, Michael L; Tang, Qianying; Kim, Chris H; Marks, Tobin J; Hersam, Mark C

2017-08-09

With the growing adoption of interconnected electronic devices in consumer and industrial applications, there is an increasing demand for robust security protocols when transmitting and receiving sensitive data. Toward this end, hardware true random number generators (TRNGs), commonly used to create encryption keys, offer significant advantages over software pseudorandom number generators. However, the vast network of devices and sensors envisioned for the "Internet of Things" will require small, low-cost, and mechanically flexible TRNGs with low computational complexity. These rigorous constraints position solution-processed semiconducting single-walled carbon nanotubes (SWCNTs) as leading candidates for next-generation security devices. Here, we demonstrate the first TRNG using static random access memory (SRAM) cells based on solution-processed SWCNTs that digitize thermal noise to generate random bits. This bit generation strategy can be readily implemented in hardware with minimal transistor and computational overhead, resulting in an output stream that passes standardized statistical tests for randomness. By using solution-processed semiconducting SWCNTs in a low-power, complementary architecture to achieve TRNG, we demonstrate a promising approach for improving the security of printable and flexible electronics.

ATCA digital controller hardware for vertical stabilization of plasmas in tokamaks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Batista, A. J. N.; Sousa, J.; Varandas, C. A. F.

2006-10-15

The efficient vertical stabilization (VS) of plasmas in tokamaks requires a fast reaction of the VS controller, for example, after detection of edge localized modes (ELM). For controlling the effects of very large ELMs a new digital control hardware, based on the Advanced Telecommunications Computing Architecture trade mark sign (ATCA), is being developed aiming to reduce the VS digital control loop cycle (down to an optimal value of 10 {mu}s) and improve the algorithm performance. The system has 1 ATCA trade mark sign processor module and up to 12 ATCA trade mark sign control modules, each one with 32 analogmore » input channels (12 bit resolution), 4 analog output channels (12 bit resolution), and 8 digital input/output channels. The Aurora trade mark sign and PCI Express trade mark sign communication protocols will be used for data transport, between modules, with expected latencies below 2 {mu}s. Control algorithms are implemented on a ix86 based processor with 6 Gflops and on field programmable gate arrays with 80 GMACS, interconnected by serial gigabit links in a full mesh topology.« less

Simulation Modeling and Performance Evaluation of Space Networks

NASA Technical Reports Server (NTRS)

Jennings, Esther H.; Segui, John

2006-01-01

In space exploration missions, the coordinated use of spacecraft as communication relays increases the efficiency of the endeavors. To conduct trade-off studies of the performance and resource usage of different communication protocols and network designs, JPL designed a comprehensive extendable tool, the Multi-mission Advanced Communications Hybrid Environment for Test and Evaluation (MACHETE). The design and development of MACHETE began in 2000 and is constantly evolving. Currently, MACHETE contains Consultative Committee for Space Data Systems (CCSDS) protocol standards such as Proximity-1, Advanced Orbiting Systems (AOS), Packet Telemetry/Telecommand, Space Communications Protocol Specification (SCPS), and the CCSDS File Delivery Protocol (CFDP). MACHETE uses the Aerospace Corporation s Satellite Orbital Analysis Program (SOAP) to generate the orbital geometry information and contact opportunities. Matlab scripts provide the link characteristics. At the core of MACHETE is a discrete event simulator, QualNet. Delay Tolerant Networking (DTN) is an end-to-end architecture providing communication in and/or through highly stressed networking environments. Stressed networking environments include those with intermittent connectivity, large and/or variable delays, and high bit error rates. To provide its services, the DTN protocols reside at the application layer of the constituent internets, forming a store-and-forward overlay network. The key capabilities of the bundling protocols include custody-based reliability, ability to cope with intermittent connectivity, ability to take advantage of scheduled and opportunistic connectivity, and late binding of names to addresses. In this presentation, we report on the addition of MACHETE models needed to support DTN, namely: the Bundle Protocol (BP) model. To illustrate the use of MACHETE with the additional DTN model, we provide an example simulation to benchmark its performance. We demonstrate the use of the DTN protocol and discuss statistics gathered concerning the total time needed to simulate numerous bundle transmissions

Analysis of practical backoff protocols for contention resolution with multiple servers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldberg, L.A.; MacKenzie, P.D.

Backoff protocols are probably the most widely used protocols for contention resolution in multiple access channels. In this paper, we analyze the stochastic behavior of backoff protocols for contention resolution among a set of clients and servers, each server being a multiple access channel that deals with contention like an Ethernet channel. We use the standard model in which each client generates requests for a given server according to a Bemoulli distribution with a specified mean. The client-server request rate of a system is the maximum over all client-server pairs (i, j) of the sum of all request rates associatedmore » with either client i or server j. Our main result is that any superlinear polynomial backoff protocol is stable for any multiple-server system with a sub-unit client-server request rate. We confirm the practical relevance of our result by demonstrating experimentally that the average waiting time of requests is very small when such a system is run with reasonably few clients and reasonably small request rates such as those that occur in actual ethernets. Our result is the first proof of stability for any backoff protocol for contention resolution with multiple servers. Our result is also the first proof that any weakly acknowledgment based protocol is stable for contention resolution with multiple servers and such high request rates. Two special cases of our result are of interest. Hastad, Leighton and Rogoff have shown that for a single-server system with a sub-unit client-server request rate any modified superlinear polynomial backoff protocol is stable. These modified backoff protocols are similar to standard backoff protocols but require more random bits to implement. The special case of our result in which there is only one server extends the result of Hastad, Leighton and Rogoff to standard (practical) backoff protocols. Finally, our result applies to dynamic routing in optical networks.« less

Fastener Starter

NASA Technical Reports Server (NTRS)

Chandler, Faith; Garton, Harry; Valentino, Bill; Amett, Mike

2005-01-01

The Fastener Starter is a creative solution to prevent the loss of small fasteners during their installation. This is the only currently available tool that can firmly grip and hold a single screw, bolt, nut, washer, spacer, or any combination of these parts. Other commercially available fastener starters are unable to accommodate a variety of parts simultaneously. The Fastener Starter is a more capable and easier tool to use than prior tools. Its compact size allows it to be used effectively in cramped, difficult-to-see locations. Its design also allows it to be used with or without handles and extenders in other difficult-to-reach locations. It provides better protection against cross threading and loss of fasteners and associated parts. The Fastener Starter is non-magnetic and does not off-gas, thus meeting flight hardware requirements. The Fastener Starter incorporates a combination of features of several commercially available tools, providing an improved means of installing small fasteners. The Fastener Starter includes a custom molded insert that can be removed easily and replaced with a conventional tool bit (e.g., a screwdriver or hex-driver bit). When used with the insert, the Fastener Starter prevents cross threading and damage to internal threaded holes. This is achieved by allowing the fastener to slip within the tool insert when used without a conventional tool bit. Alternatively, without the insert and with a tool bit, the Fastener Starter can torque a fastener. The Fastener Starter has a square recess hole that accepts a conventional square drive handle or extension to accommodate a variety of applications by providing flexibility in handle style and length.

Analysis of the convective characteristics during the mutual evolution of an inverted trough/low vortex and its induced rainstorm over the northeastern Sichuan basin, China

NASA Astrophysics Data System (ADS)

Chen, Yongren; Li, Yueqing; Qi, Dongmei

2018-04-01

Based on a variety of ground-based and satellite-derived observational data, we studied a flood-rainstorm event that occurred over northeastern Sichuan, China, from the 8th to the 14th of September 2014. Four periods of mesoscale convective system (MCS) activity were found during a mutual evolution process of an 850-hPa basin inverted trough (BIT) and 850-hPa basin low vortex (BLV). Among them, the first three periods occurred in an alternating evolution of the BIT and BLV (called the first stage), and then, the fourth period was stimulated by continuous activity of the BLV (called the second stage). During the first stage, MCSs enhanced (weakened) under the situation of the BIT (BLV), and then during the second stage MCSs developed to their strongest levels. Further analysis of the reasons behind the enhancement and weakening of MCSs revealed an obvious characteristic of upper level (lower level) positive (negative) divergence in the BIT situation of the first stage and BLV situation of the second stage. By comparison, under the BLV situation of the first stage, the vertical helicity was larger in the upward airflow of the zonal circulation, and the direction of the wet Q-vector was toward the ascending airflow in the vertical direction. In the horizontal direction, the negative divergence of the wet Q-vector corresponded to the position of water vapor flux convergence. In addition, in the early development of convection, sounding data showed a humidity profile of dry upper and wet lower levels, as well as a larger value of convective available potential energy, which triggered convective activity under the favorable dynamic conditions of atmosphere. When the above characteristics weakened, the convective activity also weakened. Therefore, the formation of multiple convective systems was closely related to the adjustment in atmospheric conditions around the BIT and BLV.

The microcomputer workstation - An alternate hardware architecture for remotely sensed image analysis

NASA Technical Reports Server (NTRS)

Erickson, W. K.; Hofman, L. B.; Donovan, W. E.

1984-01-01

Difficulties regarding the digital image analysis of remotely sensed imagery can arise in connection with the extensive calculations required. In the past, an expensive large to medium mainframe computer system was needed for performing these calculations. For image-processing applications smaller minicomputer-based systems are now used by many organizations. The costs for such systems are still in the range from $100K to $300K. Recently, as a result of new developments, the use of low-cost microcomputers for image processing and display systems appeared to have become feasible. These developments are related to the advent of the 16-bit microprocessor and the concept of the microcomputer workstation. Earlier 8-bit microcomputer-based image processing systems are briefly examined, and a computer workstation architecture is discussed. Attention is given to a microcomputer workstation developed by Stanford University, and the design and implementation of a workstation network.

Data recording and playback on video tape--a multi-channel analog interface for a digital audio processor system.

PubMed

Blaettler, M; Bruegger, A; Forster, I C; Lehareinger, Y

1988-03-01

The design of an analog interface to a digital audio signal processor (DASP)-video cassette recorder (VCR) system is described. The complete system represents a low-cost alternative to both FM instrumentation tape recorders and multi-channel chart recorders. The interface or DASP input-output unit described in this paper enables the recording and playback of up to 12 analog channels with a maximum of 12 bit resolution and a bandwidth of 2 kHz per channel. Internal control and timing in the recording component of the interface is performed using ROMs which can be reprogrammed to suit different analog-to-digital converter hardware. Improvement in the bandwidth specifications is possible by connecting channels in parallel. A parallel 16 bit data output port is provided for direct transfer of the digitized data to a computer.

NB-PLC channel modelling with cyclostationary noise addition & OFDM implementation for smart grid

NASA Astrophysics Data System (ADS)

Thomas, Togis; Gupta, K. K.

2016-03-01

Power line communication (PLC) technology can be a viable solution for the future ubiquitous networks because it provides a cheaper alternative to other wired technology currently being used for communication. In smart grid Power Line Communication (PLC) is used to support communication with low rate on low voltage (LV) distribution network. In this paper, we propose the channel modelling of narrowband (NB) PLC in the frequency range 5 KHz to 500 KHz by using ABCD parameter with cyclostationary noise addition. Behaviour of the channel was studied by the addition of 11KV/230V transformer, by varying load location and load. Bit error rate (BER) Vs signal to noise ratio SNR) was plotted for the proposed model by employing OFDM. Our simulation results based on the proposed channel model show an acceptable performance in terms of bit error rate versus signal to noise ratio, which enables communication required for smart grid applications.

Method of joint bit rate/modulation format identification and optical performance monitoring using asynchronous delay-tap sampling for radio-over-fiber systems

NASA Astrophysics Data System (ADS)

Guesmi, Latifa; Menif, Mourad

2016-08-01

In the context of carrying a wide variety of modulation formats and data rates for home networks, the study covers the radio-over-fiber (RoF) technology, where the need for an alternative way of management, automated fault diagnosis, and formats identification is expressed. Also, RoF signals in an optical link are impaired by various linear and nonlinear effects including chromatic dispersion, polarization mode dispersion, amplified spontaneous emission noise, and so on. Hence, for this purpose, we investigated the sampling method based on asynchronous delay-tap sampling in conjunction with a cross-correlation function for the joint bit rate/modulation format identification and optical performance monitoring. Three modulation formats with different data rates are used to demonstrate the validity of this technique, where the identification accuracy and the monitoring ranges reached high values.

Duplex Direct Data Distribution System

NASA Technical Reports Server (NTRS)

Greenfield, Israel (Technical Monitor)

2001-01-01

The NASA Glenn Research Center (GRC) is developing and demonstrating communications and network technologies that are helping to enable the near-Earth space Internet. GRC envisions several service categories. The first of these categories is direct data distribution or D3 (pronounced "D-cubed"). Commercially provided D3 will make it possible to download a data set from a spacecraft, like the International Space Station. as easily as one can extract a file from a remote server today, using a file transfer protocol. In a second category, NASA spacecraft will make use of commercial satellite communication (SATCOM) systems. Some of those services will come from purchasing time on unused transponders that cover landmasses. While it is likely there will be gaps in service coverage, Internet services should be available using these systems. This report addresses alternative methods of implementing a full duplex enhancement of the GRC developed experimental Ka-Band Direct Data Distribution (D3) space-to-ground communication link. The resulting duplex version is called the Duplex Direct Data Distribution (D4) system. The D4 system is intended to provide high-data-rate commercial direct or internet-based communications service between the NASA spacecraft in low earth orbit (LEO) and the respective principal investigators associated with these spacecraft. Candidate commercial services were assessed regarding their near-term potential to meet NASA requirements. Candidates included Ka-band and V-band geostationary orbit and non-geostationary orbit satellite relay services and direct downlink ("LEO teleport") services. End-to-end systems concepts were examined and characterized in terms of alternative link layer architectures. Alternatives included a Direct Link, a Relay Link, a Hybrid Link, and a Dual Mode Link. The direct link assessment examined sample ground terminal placements and antenna angle issues. The SATCOM-based alternatives examined existing or proposed commercial SATCOM services that could be available in the 2005 time frame. The alternatives were evaluated and compared in terms of average daily system throughput and cost per bit. Throughput was estimated based on hypothetical scenarios supporting the International Space Station and polar orbiting missions. The feasibility of using standard TCP and a modified TCP was evaluated and risks were identified. An estimate of the TCP acknowledgment data rate required to support a return channel rate of 622 Mbps was developed using OPNET.

Enhanced protocol for real-time transmission of echocardiograms over wireless channels.

PubMed

Cavero, Eva; Alesanco, Alvaro; García, Jose

2012-11-01

This paper presents a methodology to transmit clinical video over wireless networks in real-time. A 3-D set partitioning in hierarchical trees compression prior to transmission is proposed. In order to guarantee the clinical quality of the compressed video, a clinical evaluation specific to each video modality has to be made. This evaluation indicates the minimal transmission rate necessary for an accurate diagnosis. However, the channel conditions produce errors and distort the video. A reliable application protocol is therefore proposed using a hybrid solution in which either retransmission or retransmission combined with forward error correction (FEC) techniques are used, depending on the channel conditions. In order to analyze the proposed methodology, the 2-D mode of an echocardiogram has been assessed. A bandwidth of 200 kbps is necessary to guarantee its clinical quality. The transmission using the proposed solution and retransmission and FEC techniques working separately have been simulated and compared in high-speed uplink packet access (HSUPA) and worldwide interoperability for microwave access (WiMAX) networks. The proposed protocol achieves guaranteed clinical quality for bit error rates higher than with the other protocols, being for a mobile speed of 60 km/h up to 3.3 times higher for HSUPA and 10 times for WiMAX.

Development of a multilocus-based approach for sponge (phylum Porifera) identification: refinement and limitations.

PubMed

Yang, Qi; Franco, Christopher M M; Sorokin, Shirley J; Zhang, Wei

2017-02-02

For sponges (phylum Porifera), there is no reliable molecular protocol available for species identification. To address this gap, we developed a multilocus-based Sponge Identification Protocol (SIP) validated by a sample of 37 sponge species belonging to 10 orders from South Australia. The universal barcode COI mtDNA, 28S rRNA gene (D3-D5), and the nuclear ITS1-5.8S-ITS2 region were evaluated for their suitability and capacity for sponge identification. The highest Bit Score was applied to infer the identity. The reliability of SIP was validated by phylogenetic analysis. The 28S rRNA gene and COI mtDNA performed better than the ITS region in classifying sponges at various taxonomic levels. A major limitation is that the databases are not well populated and possess low diversity, making it difficult to conduct the molecular identification protocol. The identification is also impacted by the accuracy of the morphological classification of the sponges whose sequences have been submitted to the database. Re-examination of the morphological identification further demonstrated and improved the reliability of sponge identification by SIP. Integrated with morphological identification, the multilocus-based SIP offers an improved protocol for more reliable and effective sponge identification, by coupling the accuracy of different DNA markers.

Development of a multilocus-based approach for sponge (phylum Porifera) identification: refinement and limitations

PubMed Central

Yang, Qi; Franco, Christopher M. M.; Sorokin, Shirley J.; Zhang, Wei

2017-01-01

For sponges (phylum Porifera), there is no reliable molecular protocol available for species identification. To address this gap, we developed a multilocus-based Sponge Identification Protocol (SIP) validated by a sample of 37 sponge species belonging to 10 orders from South Australia. The universal barcode COI mtDNA, 28S rRNA gene (D3–D5), and the nuclear ITS1-5.8S-ITS2 region were evaluated for their suitability and capacity for sponge identification. The highest Bit Score was applied to infer the identity. The reliability of SIP was validated by phylogenetic analysis. The 28S rRNA gene and COI mtDNA performed better than the ITS region in classifying sponges at various taxonomic levels. A major limitation is that the databases are not well populated and possess low diversity, making it difficult to conduct the molecular identification protocol. The identification is also impacted by the accuracy of the morphological classification of the sponges whose sequences have been submitted to the database. Re-examination of the morphological identification further demonstrated and improved the reliability of sponge identification by SIP. Integrated with morphological identification, the multilocus-based SIP offers an improved protocol for more reliable and effective sponge identification, by coupling the accuracy of different DNA markers. PMID:28150727

Proof-of-principle test of coherent-state continuous variable quantum key distribution through turbulent atmosphere (Conference Presentation)

NASA Astrophysics Data System (ADS)

Derkach, Ivan D.; Peuntinger, Christian; Ruppert, László; Heim, Bettina; Gunthner, Kevin; Usenko, Vladyslav C.; Elser, Dominique; Marquardt, Christoph; Filip, Radim; Leuchs, Gerd

2016-10-01

Continuous-variable quantum key distribution is a practical application of quantum information theory that is aimed at generation of secret cryptographic key between two remote trusted parties and that uses multi-photon quantum states as carriers of key bits. Remote parties share the secret key via a quantum channel, that presumably is under control of of an eavesdropper, and which properties must be taken into account in the security analysis. Well-studied fiber-optical quantum channels commonly possess stable transmittance and low noise levels, while free-space channels represent a simpler, less demanding and more flexible alternative, but suffer from atmospheric effects such as turbulence that in particular causes a non-uniform transmittance distribution referred to as fading. Nonetheless free-space channels, providing an unobstructed line-of-sight, are more apt for short, mid-range and potentially long-range (using satellites) communication and will play an important role in the future development and implementation of QKD networks. It was previously theoretically shown that coherent-state CV QKD should be in principle possible to implement over a free-space fading channel, but strong transmittance fluctuations result in the significant modulation-dependent channel excess noise. In this regime the post-selection of highly transmitting sub-channels may be needed, which can even restore the security of the protocol in the strongly turbulent channels. We now report the first proof-of-principle experimental test of coherent state CV QKD protocol using different levels Gaussian modulation over a mid-range (1.6-kilometer long) free-space atmospheric quantum channel. The transmittance of the link was characterized using intensity measurements for the reference but channel estimation using the modulated coherent states was also studied. We consider security against Gaussian collective attacks, that were shown to be optimal against CV QKD protocols . We assumed a general entangling cloner collective attack (modeled using data obtained from the state measurement results on both trusted sides of the protocol), that allows to purify the noise added in the quantum channel . Our security analysis of coherent-state protocol also took into account the effect of imperfect channel estimation, limited post-processing efficiency and finite data ensemble size on the performance of the protocol. In this regime we observe the positive key rate even without the need of applying post-selection. We show the positive improvement of the key rate with increase of the modulation variance, still remaining low enough to tolerate the transmittance fluctuations. The obtained results show that coherent-state CV QKD protocol that uses real free-space atmospheric channel can withstand negative influence of transmittance fluctuations, limited post-processing efficiency, imperfect channel estimation and other finite-size effects, and be successfully implemented. Our result paves the way to the full-scale implementation of the CV QKD in real free-space channels at mid-range distances.

Practical scheme for error control using feedback

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarovar, Mohan; Milburn, Gerard J.; Ahn, Charlene

2004-05-01

We describe a scheme for quantum-error correction that employs feedback and weak measurement rather than the standard tools of projective measurement and fast controlled unitary gates. The advantage of this scheme over previous protocols [for example, Ahn et al. Phys. Rev. A 65, 042301 (2001)], is that it requires little side processing while remaining robust to measurement inefficiency, and is therefore considerably more practical. We evaluate the performance of our scheme by simulating the correction of bit flips. We also consider implementation in a solid-state quantum-computation architecture and estimate the maximal error rate that could be corrected with current technology.

Subcarrier Wave Quantum Key Distribution in Telecommunication Network with Bitrate 800 kbit/s

NASA Astrophysics Data System (ADS)

Gleim, A. V.; Nazarov, Yu. V.; Egorov, V. I.; Smirnov, S. V.; Bannik, O. I.; Chistyakov, V. V.; Kynev, S. M.; Anisimov, A. A.; Kozlov, S. A.; Vasiliev, V. N.

2015-09-01

In the course of work on creating the first quantum communication network in Russia we demonstrated quantum key distribution in metropolitan optical network infrastructure. A single-pass subcarrier wave quantum cryptography scheme was used in the experiments. BB84 protocol with strong reference was chosen for performing key distribution. The registered sifted key rate in an optical cable with 1.5 dB loss was 800 Kbit/s. Signal visibility exceeded 98%, and quantum bit error rate value was 1%. The achieved result is a record for this type of systems.

Projection of two biphoton qutrits onto a maximally entangled state.

PubMed

Halevy, A; Megidish, E; Shacham, T; Dovrat, L; Eisenberg, H S

2011-04-01

Bell state measurements, in which two quantum bits are projected onto a maximally entangled state, are an essential component of quantum information science. We propose and experimentally demonstrate the projection of two quantum systems with three states (qutrits) onto a generalized maximally entangled state. Each qutrit is represented by the polarization of a pair of indistinguishable photons-a biphoton. The projection is a joint measurement on both biphotons using standard linear optics elements. This demonstration enables the realization of quantum information protocols with qutrits, such as teleportation and entanglement swapping. © 2011 American Physical Society

Bennett clocking of quantum-dot cellular automata and the limits to binary logic scaling.

PubMed

Lent, Craig S; Liu, Mo; Lu, Yuhui

2006-08-28

We examine power dissipation in different clocking schemes for molecular quantum-dot cellular automata (QCA) circuits. 'Landauer clocking' involves the adiabatic transition of a molecular cell from the null state to an active state carrying data. Cell layout creates devices which allow data in cells to interact and thereby perform useful computation. We perform direct solutions of the equation of motion for the system in contact with the thermal environment and see that Landauer's Principle applies: one must dissipate an energy of at least k(B)T per bit only when the information is erased. The ideas of Bennett can be applied to keep copies of the bit information by echoing inputs to outputs, thus embedding any logically irreversible circuit in a logically reversible circuit, at the cost of added circuit complexity. A promising alternative which we term 'Bennett clocking' requires only altering the timing of the clocking signals so that bit information is simply held in place by the clock until a computational block is complete, then erased in the reverse order of computation. This approach results in ultralow power dissipation without additional circuit complexity. These results offer a concrete example in which to consider recent claims regarding the fundamental limits of binary logic scaling.

Bennett clocking of quantum-dot cellular automata and the limits to binary logic scaling

NASA Astrophysics Data System (ADS)

Lent, Craig S.; Liu, Mo; Lu, Yuhui

2006-08-01

We examine power dissipation in different clocking schemes for molecular quantum-dot cellular automata (QCA) circuits. 'Landauer clocking' involves the adiabatic transition of a molecular cell from the null state to an active state carrying data. Cell layout creates devices which allow data in cells to interact and thereby perform useful computation. We perform direct solutions of the equation of motion for the system in contact with the thermal environment and see that Landauer's Principle applies: one must dissipate an energy of at least kBT per bit only when the information is erased. The ideas of Bennett can be applied to keep copies of the bit information by echoing inputs to outputs, thus embedding any logically irreversible circuit in a logically reversible circuit, at the cost of added circuit complexity. A promising alternative which we term 'Bennett clocking' requires only altering the timing of the clocking signals so that bit information is simply held in place by the clock until a computational block is complete, then erased in the reverse order of computation. This approach results in ultralow power dissipation without additional circuit complexity. These results offer a concrete example in which to consider recent claims regarding the fundamental limits of binary logic scaling.

Families of quantum fingerprinting protocols

NASA Astrophysics Data System (ADS)

Lovitz, Benjamin; Lütkenhaus, Norbert

2018-03-01

We introduce several families of quantum fingerprinting protocols to evaluate the equality function on two n -bit strings in the simultaneous message passing model. The original quantum fingerprinting protocol uses a tensor product of a small number of O (logn ) -qubit high-dimensional signals [H. Buhrman et al., Phys. Rev. Lett. 87, 167902 (2001), 10.1103/PhysRevLett.87.167902], whereas a recently proposed optical protocol uses a tensor product of O (n ) single-qubit signals, while maintaining the O (logn ) information leakage of the original protocol [J. M. Arazola and N. Lütkenhaus, Phys. Rev. A 89, 062305 (2014), 10.1103/PhysRevA.89.062305]. We find a family of protocols which interpolate between the original and optical protocols while maintaining the O (logn ) information leakage, thus demonstrating a tradeoff between the number of signals sent and the dimension of each signal. There has been interest in experimental realization of the recently proposed optical protocol using coherent states [F. Xu et al., Nat. Commun. 6, 8735 (2015), 10.1038/ncomms9735; J.-Y. Guan et al., Phys. Rev. Lett. 116, 240502 (2016), 10.1103/PhysRevLett.116.240502], but as the required number of laser pulses grows linearly with the input size n , eventual challenges for the long-time stability of experimental setups arise. We find a coherent state protocol which reduces the number of signals by a factor 1/2 while also reducing the information leakage. Our reduction makes use of a simple modulation scheme in optical phase space, and we find that more complex modulation schemes are not advantageous. Using a similar technique, we improve a recently proposed coherent state protocol for evaluating the Euclidean distance between two real unit vectors [N. Kumar et al., Phys. Rev. A 95, 032337 (2017), 10.1103/PhysRevA.95.032337] by reducing the number of signals by a factor 1/2 and also reducing the information leakage.

All-optical clock recovery, photonic balancing, and saturated asymmetric filtering for fiber optic communication systems

NASA Astrophysics Data System (ADS)

Parsons, Earl Ryan

In this dissertation I investigated a multi-channel and multi-bit rate all-optical clock recovery device. This device, a birefringent Fabry-Perot resonator, had previously been demonstrated to simultaneously recover the clock signal from 10 wavelength channels operating at 10 Gb/s and one channel at 40 Gb/s. Similar to clock signals recovered from a conventional Fabry-Perot resonator, the clock signal from the birefringent resonator suffers from a bit pattern effect. I investigated this bit pattern effect for birefringent resonators numerically and experimentally and found that the bit pattern effect is less prominent than for clock signals from a conventional Fabry-Perot resonator. I also demonstrated photonic balancing which is an all-optical alternative to electrical balanced detection for phase shift keyed signals. An RZ-DPSK data signal was demodulated using a delay interferometer. The two logically opposite outputs from the delay interferometer then counter-propagated in a saturated SOA. This process created a differential signal which used all the signal power present in two consecutive symbols. I showed that this scheme could provide an optical alternative to electrical balanced detection by reducing the required OSNR by 3 dB. I also show how this method can provide amplitude regeneration to a signal after modulation format conversion. In this case an RZ-DPSK signal was converted to an amplitude modulation signal by the delay interferometer. The resulting amplitude modulated signal is degraded by both the amplitude noise and the phase noise of the original signal. The two logically opposite outputs from the delay interferometer again counter-propagated in a saturated SOA. Through limiting amplification and noise modulation this scheme provided amplitude regeneration and improved the Q-factor of the demodulated signal by 3.5 dB. Finally I investigated how SPM provided by the SOA can provide a method to reduce the in-band noise of a communication signal. The marks, which represented data, experienced a spectral shift due to SPM while the spaces, which consisted of noise, did not. A bandpass filter placed after the SOA then selected the signal and filtered out what was originally in-band noise. The receiver sensitivity was improved by 3 dB.

Searching for the Holy Grail of Learning Outcomes. SERU Project and Consortium Research Paper. Research & Occasional Paper Series: CSHE.3.12

ERIC Educational Resources Information Center

Douglass, John Aubrey; Thomson, Gregg; Zhao, Chun-Mei

2012-01-01

The search for the Holy Grail to measure learning gains started in the US, but the Organisation for Economic Co-operation and Development (OECD) wants to take it global. Here we tell a bit of this story and raise serious questions regarding the validity of the Collegiate Learning Assessment test and suggest there are alternatives. The merit of the…

32-Bit-Wide Memory Tolerates Failures

NASA Technical Reports Server (NTRS)

Buskirk, Glenn A.

1990-01-01

Electronic memory system of 32-bit words corrects bit errors caused by some common type of failures - even failure of entire 4-bit-wide random-access-memory (RAM) chip. Detects failure of two such chips, so user warned that ouput of memory may contain errors. Includes eight 4-bit-wide DRAM's configured so each bit of each DRAM assigned to different one of four parallel 8-bit words. Each DRAM contributes only 1 bit to each 8-bit word.

Alternative parallel ring protocols

NASA Technical Reports Server (NTRS)

Mukkamala, R.; Foudriat, E. C.; Maly, Kurt J.; Kale, V.

1990-01-01

Communication protocols are know to influence the utilization and performance of communication network. The effect of two token ring protocols on a gigabit network with multiple ring structure is investigated. In the first protocol, a mode sends at most one message on receiving a token. In the second protocol, a mode sends all the waiting messages when a token is received. The behavior of these protocols is shown to be highly dependent on the number of rings as well as the load in the network.

Mission Control Operations: Employing a New High Performance Design for Communications Links Supporting Exploration Programs

NASA Technical Reports Server (NTRS)

Jackson, Dan E., Jr.

2015-01-01

The planetary exploration programs demand a totally new examination of data multiplexing, digital communications protocols and data transmission principles for both ground and spacecraft operations. Highly adaptive communications devices on-board and on the ground must provide the greatest possible transmitted data density between deployed crew personnel, spacecraft and ground control teams. Regarding these requirements, this proposal borrows from research into quantum mechanical computing by applying the concept of a qubit, a single bit that represents 16 states, to radio frequency (RF) communications link design for exploration programs. This concept of placing multiple character values into a single data bit can easily make the evolutionary steps needed to meet exploration mission demands. To move the qubit from the quantum mechanical research laboratory into long distance RF data transmission, this proposal utilizes polarization modulation of the RF carrier signal to represent numbers from zero to fifteen. It introduces the concept of a binary-to-hexadecimal converter that quickly chops any data stream into 16-bit words and connects variously polarized feedhorns to a single-frequency radio transmitter. Further, the concept relies on development of a receiver that uses low-noise amplifiers and an antenna array to quickly assess carrier polarity and perform hexadecimal to binary conversion. Early testbed experiments using the International Space Station (ISS) as an operations laboratory can be implemented to provide the most cost-effective return for research investment. The improvement in signal-to-noise ratio while supporting greater baseband data rates that could be achieved through this concept justifies its consideration for long-distance exploration programs.

Comparison of a row-column speller vs. a novel lateral single-character speller: assessment of BCI for severe motor disabled patients.

PubMed

Pires, Gabriel; Nunes, Urbano; Castelo-Branco, Miguel

2012-06-01

Non-invasive brain-computer interface (BCI) based on electroencephalography (EEG) offers a new communication channel for people suffering from severe motor disorders. This paper presents a novel P300-based speller called lateral single-character (LSC). The LSC performance is compared to that of the standard row-column (RC) speller. We developed LSC, a single-character paradigm comprising all letters of the alphabet following an event strategy that significantly reduces the time for symbol selection, and explores the intrinsic hemispheric asymmetries in visual perception to improve the performance of the BCI. RC and LSC paradigms were tested by 10 able-bodied participants, seven participants with amyotrophic lateral sclerosis (ALS), five participants with cerebral palsy (CP), one participant with Duchenne muscular dystrophy (DMD), and one participant with spinal cord injury (SCI). The averaged results, taking into account all participants who were able to control the BCI online, were significantly higher for LSC, 26.11 bit/min and 89.90% accuracy, than for RC, 21.91 bit/min and 88.36% accuracy. The two paradigms produced different waveforms and the signal-to-noise ratio was significantly higher for LSC. Finally, the novel LSC also showed new discriminative features. The results suggest that LSC is an effective alternative to RC, and that LSC still has a margin for potential improvement in bit rate and accuracy. The high bit rates and accuracy of LSC are a step forward for the effective use of BCI in clinical applications. Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Robust QKD-based private database queries based on alternative sequences of single-qubit measurements

NASA Astrophysics Data System (ADS)

Yang, YuGuang; Liu, ZhiChao; Chen, XiuBo; Zhou, YiHua; Shi, WeiMin

2017-12-01

Quantum channel noise may cause the user to obtain a wrong answer and thus misunderstand the database holder for existing QKD-based quantum private query (QPQ) protocols. In addition, an outside attacker may conceal his attack by exploiting the channel noise. We propose a new, robust QPQ protocol based on four-qubit decoherence-free (DF) states. In contrast to existing QPQ protocols against channel noise, only an alternative fixed sequence of single-qubit measurements is needed by the user (Alice) to measure the received DF states. This property makes it easy to implement the proposed protocol by exploiting current technologies. Moreover, to retain the advantage of flexible database queries, we reconstruct Alice's measurement operators so that Alice needs only conditioned sequences of single-qubit measurements.

Effect of PDC bit design and confining pressure on bit-balling tendencies while drilling shale using water base mud

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hariharan, P.R.; Azar, J.J.

1996-09-01

A good majority of all oilwell drilling occurs in shale and other clay-bearing rocks. In the light of relatively fewer studies conducted, the problem of bit-balling in PDC bits while drilling shale has been addressed with the primary intention of attempting to quantify the degree of balling, as well as to investigate the influence of bit design and confining pressures. A series of full-scale laboratory drilling tests under simulated down hole conditions were conducted utilizing seven different PDC bits in Catoosa shale. Test results have indicated that the non-dimensional parameter R{sub d} [(bit torque).(weight-on-bit)/(bit diameter)] is a good indicator ofmore » the degree of bit-balling and that it correlated well with Specific-Energy. Furthermore, test results have shown bit-profile and bit-hydraulic design to be key parameters of bit design that dictate the tendency of balling in shales under a given set of operating conditions. A bladed bit was noticed to ball less compared to a ribbed or open-faced bit. Likewise, related to bit profile, test results have indicated that the parabolic profile has a lesser tendency to ball compared to round and flat profiles. The tendency of PDC bits to ball was noticed to increase with increasing confining pressures for the set of drilling conditions used.« less

An Enhanced LoRaWAN Security Protocol for Privacy Preservation in IoT with a Case Study on a Smart Factory-Enabled Parking System.

PubMed

You, Ilsun; Kwon, Soonhyun; Choudhary, Gaurav; Sharma, Vishal; Seo, Jung Taek

2018-06-08

The Internet of Things (IoT) utilizes algorithms to facilitate intelligent applications across cities in the form of smart-urban projects. As the majority of devices in IoT are battery operated, their applications should be facilitated with a low-power communication setup. Such facility is possible through the Low-Power Wide-Area Network (LPWAN), but at a constrained bit rate. For long-range communication over LPWAN, several approaches and protocols are adopted. One such protocol is the Long-Range Wide Area Network (LoRaWAN), which is a media access layer protocol for long-range communication between the devices and the application servers via LPWAN gateways. However, LoRaWAN comes with fewer security features as a much-secured protocol consumes more battery because of the exorbitant computational overheads. The standard protocol fails to support end-to-end security and perfect forward secrecy while being vulnerable to the replay attack that makes LoRaWAN limited in supporting applications where security (especially end-to-end security) is important. Motivated by this, an enhanced LoRaWAN security protocol is proposed, which not only provides the basic functions of connectivity between the application server and the end device, but additionally averts these listed security issues. The proposed protocol is developed with two options, the Default Option (DO) and the Security-Enhanced Option (SEO). The protocol is validated through Burrows⁻Abadi⁻Needham (BAN) logic and the Automated Validation of Internet Security Protocols and Applications (AVISPA) tool. The proposed protocol is also analyzed for overheads through system-based and low-power device-based evaluations. Further, a case study on a smart factory-enabled parking system is considered for its practical application. The results, in terms of network latency with reliability fitting and signaling overheads, show paramount improvements and better performance for the proposed protocol compared with the two handshake options, Pre-Shared Key (PSK) and Elliptic Curve Cryptography (ECC), of Datagram Transport Layer Security (DTLS).

Detecting relay attacks on RFID communication systems using quantum bits

NASA Astrophysics Data System (ADS)

Jannati, Hoda; Ardeshir-Larijani, Ebrahim

2016-11-01

RFID systems became widespread in variety of applications because of their simplicity in manufacturing and usability. In the province of critical infrastructure protection, RFID systems are usually employed to identify and track people, objects and vehicles that enter restricted areas. The most important vulnerability which is prevalent among all protocols employed in RFID systems is against relay attacks. Until now, to protect RFID systems against this kind of attack, the only approach is the utilization of distance-bounding protocols which are not applicable over low-cost devices such as RFID passive tags. This work presents a novel technique using emerging quantum technologies to detect relay attacks on RFID systems. Recently, it is demonstrated that quantum key distribution (QKD) can be implemented in a client-server scheme where client only requires an on-chip polarization rotator that may be integrated into a handheld device. Now we present our technique for a tag-reader scenario which needs similar resources as the mentioned QKD scheme. We argue that our technique requires less resources and provides lower probability of false alarm for the system, compared with distance-bounding protocols, and may pave the way to enhance the security of current RFID systems.

Providing Internet Access to High-Resolution Lunar Images

NASA Technical Reports Server (NTRS)

Plesea, Lucian

2008-01-01

The OnMoon server is a computer program that provides Internet access to high-resolution Lunar images, maps, and elevation data, all suitable for use in geographical information system (GIS) software for generating images, maps, and computational models of the Moon. The OnMoon server implements the Open Geospatial Consortium (OGC) Web Map Service (WMS) server protocol and supports Moon-specific extensions. Unlike other Internet map servers that provide Lunar data using an Earth coordinate system, the OnMoon server supports encoding of data in Moon-specific coordinate systems. The OnMoon server offers access to most of the available high-resolution Lunar image and elevation data. This server can generate image and map files in the tagged image file format (TIFF) or the Joint Photographic Experts Group (JPEG), 8- or 16-bit Portable Network Graphics (PNG), or Keyhole Markup Language (KML) format. Image control is provided by use of the OGC Style Layer Descriptor (SLD) protocol. Full-precision spectral arithmetic processing is also available, by use of a custom SLD extension. This server can dynamically add shaded relief based on the Lunar elevation to any image layer. This server also implements tiled WMS protocol and super-overlay KML for high-performance client application programs.

Polarization entanglement purification of nonlocal microwave photons based on the cross-Kerr effect in circuit QED

NASA Astrophysics Data System (ADS)

Zhang, Hao; Liu, Qian; Xu, Xu-Sheng; Xiong, Jun; Alsaedi, Ahmed; Hayat, Tasawar; Deng, Fu-Guo

2017-11-01

Microwave photons have become very important qubits in quantum communication, as the first quantum satellite has been launched successfully. Therefore, it is a necessary and meaningful task for ensuring the high security and efficiency of microwave-based quantum communication in practice. Here, we present an original polarization entanglement purification protocol for nonlocal microwave photons based on the cross-Kerr effect in circuit quantum electrodynamics (QED). Our protocol can solve the problem that the purity of maximally entangled states used for constructing quantum channels will decrease due to decoherence from environment noise. This task is accomplished by means of the polarization parity-check quantum nondemolition (QND) detector, the bit-flipping operation, and the linear microwave elements. The QND detector is composed of several cross-Kerr effect systems which can be realized by coupling two superconducting transmission line resonators to a superconducting molecule with the N -type level structure. We give the applicable experimental parameters of QND measurement system in circuit QED and analyze the fidelities. Our protocol has good applications in long-distance quantum communication assisted by microwave photons in the future, such as satellite quantum communication.

Sensitivity of simulated deep ocean natural radiocarbon to gas exchange velocity and historical atmospheric Δ14C variations

NASA Astrophysics Data System (ADS)

Wagner, Hannes; Koeve, Wolfgang; Kriest, Iris; Oschlies, Andreas

2015-04-01

Simulated deep ocean natural radiocarbon is frequently used to assess model performance of deep ocean ventilation in Ocean General Circulation Models (OGCMs). It has been shown to be sensitive to a variety of model parameters, such as the mixing parameterization, convection scheme and vertical resolution. Here we use three different ocean models (MIT2.8, ECCO, UVic) to evaluate the sensitivity of simulated deep ocean natural radiocarbon to two other factors, while keeping the model physics constant: (1) the gas exchange velocity and (2) historic variations in atmospheric Δ^1^4C boundary conditions. We find that simulated natural Δ^1^4C decreases by 14-20 ‰ throughout the deep ocean and consistently in all three models, if the gas exchange velocity is lowered by 30 % with respect to the OCMIP-2 protocol, to become more consistent with newer estimates of the oceans uptake of bomb derived ^1^4C. Simulated deep ocean natural Δ^1^4C furthermore decreases by 3-9 ‰ throughout the deep Pacific, Indian and Southern Oceans and consistently in all three models, if the models are forced with the observed atmospheric Δ^1^4C history, instead of an often made pragmatic assumption of a constant atmospheric Δ^1^4C value of zero. Applying both improvements (gas exchange reduction, as well as atmospheric Δ^1^4C history implementation) concomitantly and accounting for the present uncertainty in gas exchange velocity estimates (between 10 and 40 % reduction with respect to the OCMIP-2 protocol) simulated deep ocean Δ^1^4C decreases by 10-30 ‰ throughout the deep Pacific, Indian and Southern Ocean. This translates to a ^1^4C-age increase of 100-300 years and indicates, that models, which in former assessments (based on the OCMIP-2 protocol) had been identified to have an accurate deep ocean ventilation, should now be regarded as rather having a bit too sluggish a ventilation. Models, which on the other hand had been identified to have a bit too fast a deep ocean ventilation, should now be regarded as rather having a more accurate ventilation.

Proper nozzle location, bit profile, and cutter arrangement affect PDC-bit performance significantly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garcia-Gavito, D.; Azar, J.J.

1994-09-01

During the past 20 years, the drilling industry has looked to new technology to halt the exponentially increasing costs of drilling oil, gas, and geothermal wells. This technology includes bit design innovations to improve overall drilling performance and reduce drilling costs. These innovations include development of drag bits that use PDC cutters, also called PDC bits, to drill long, continuous intervals of soft to medium-hard formations more economically than conventional three-cone roller-cone bits. The cost advantage is the result of higher rates of penetration (ROP's) and longer bit life obtained with the PDC bits. An experimental study comparing the effectsmore » of polycrystalline-diamond-compact (PDC)-bit design features on the dynamic pressure distribution at the bit/rock interface was conducted on a full-scale drilling rig. Results showed that nozzle location, bit profile, and cutter arrangement are significant factors in PDC-bit performance.« less

Acquisition and Retaining Granular Samples via a Rotating Coring Bit

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph; Badescu, Mircea; Sherrit, Stewart

2013-01-01

This device takes advantage of the centrifugal forces that are generated when a coring bit is rotated, and a granular sample is entered into the bit while it is spinning, making it adhere to the internal wall of the bit, where it compacts itself into the wall of the bit. The bit can be specially designed to increase the effectiveness of regolith capturing while turning and penetrating the subsurface. The bit teeth can be oriented such that they direct the regolith toward the bit axis during the rotation of the bit. The bit can be designed with an internal flute that directs the regolith upward inside the bit. The use of both the teeth and flute can be implemented in the same bit. The bit can also be designed with an internal spiral into which the various particles wedge. In another implementation, the bit can be designed to collect regolith primarily from a specific depth. For that implementation, the bit can be designed such that when turning one way, the teeth guide the regolith outward of the bit and when turning in the opposite direction, the teeth will guide the regolith inward into the bit internal section. This mechanism can be implemented with or without an internal flute. The device is based on the use of a spinning coring bit (hollow interior) as a means of retaining granular sample, and the acquisition is done by inserting the bit into the subsurface of a regolith, soil, or powder. To demonstrate the concept, a commercial drill and a coring bit were used. The bit was turned and inserted into the soil that was contained in a bucket. While spinning the bit (at speeds of 600 to 700 RPM), the drill was lifted and the soil was retained inside the bit. To prove this point, the drill was turned horizontally, and the acquired soil was still inside the bit. The basic theory behind the process of retaining unconsolidated mass that can be acquired by the centrifugal forces of the bit is determined by noting that in order to stay inside the interior of the bit, the frictional force must be greater than the weight of the sample. The bit can be designed with an internal sleeve to serve as a container for granular samples. This tube-shaped component can be extracted upon completion of the sampling, and the bottom can be capped by placing the bit onto a corklike component. Then, upon removal of the internal tube, the top section can be sealed. The novel features of this device are: center dot A mechanism of acquiring and retaining granular samples using a coring bit without a closed door. center dot An acquisition bit that has internal structure such as a waffle pattern for compartmentalizing or helical internal flute to propel the sample inside the bit and help in acquiring and retaining granular samples. center dot A bit with an internal spiral into which the various particles wedge. center dot A design that provides a method of testing frictional properties of the granular samples and potentially segregating particles based on size and density. A controlled acceleration or deceleration may be used to drop the least-frictional particles or to eventually shear the unconsolidated material near the bit center.

Research Supporting Satellite Communications Technology

NASA Technical Reports Server (NTRS)

Horan Stephen; Lyman, Raphael

2005-01-01

This report describes the second year of research effort under the grant Research Supporting Satellite Communications Technology. The research program consists of two major projects: Fault Tolerant Link Establishment and the design of an Auto-Configurable Receiver. The Fault Tolerant Link Establishment protocol is being developed to assist the designers of satellite clusters to manage the inter-satellite communications. During this second year, the basic protocol design was validated with an extensive testing program. After this testing was completed, a channel error model was added to the protocol to permit the effects of channel errors to be measured. This error generation was used to test the effects of channel errors on Heartbeat and Token message passing. The C-language source code for the protocol modules was delivered to Goddard Space Flight Center for integration with the GSFC testbed. The need for a receiver autoconfiguration capability arises when a satellite-to-ground transmission is interrupted due to an unexpected event, the satellite transponder may reset to an unknown state and begin transmitting in a new mode. During Year 2, we completed testing of these algorithms when noise-induced bit errors were introduced. We also developed and tested an algorithm for estimating the data rate, assuming an NRZ-formatted signal corrupted with additive white Gaussian noise, and we took initial steps in integrating both algorithms into the SDR test bed at GSFC.

Expeditious reconciliation for practical quantum key distribution

NASA Astrophysics Data System (ADS)

Nakassis, Anastase; Bienfang, Joshua C.; Williams, Carl J.

2004-08-01

The paper proposes algorithmic and environmental modifications to the extant reconciliation algorithms within the BB84 protocol so as to speed up reconciliation and privacy amplification. These algorithms have been known to be a performance bottleneck 1 and can process data at rates that are six times slower than the quantum channel they serve2. As improvements in single-photon sources and detectors are expected to improve the quantum channel throughput by two or three orders of magnitude, it becomes imperative to improve the performance of the classical software. We developed a Cascade-like algorithm that relies on a symmetric formulation of the problem, error estimation through the segmentation process, outright elimination of segments with many errors, Forward Error Correction, recognition of the distinct data subpopulations that emerge as the algorithm runs, ability to operate on massive amounts of data (of the order of 1 Mbit), and a few other minor improvements. The data from the experimental algorithm we developed show that by operating on massive arrays of data we can improve software performance by better than three orders of magnitude while retaining nearly as many bits (typically more than 90%) as the algorithms that were designed for optimal bit retention.

Scaleable wireless web-enabled sensor networks

NASA Astrophysics Data System (ADS)

Townsend, Christopher P.; Hamel, Michael J.; Sonntag, Peter A.; Trutor, B.; Arms, Steven W.

2002-06-01

Our goal was to develop a long life, low cost, scalable wireless sensing network, which collects and distributes data from a wide variety of sensors over the internet. Time division multiple access was employed with RF transmitter nodes (each w/unique16 bit address) to communicate digital data to a single receiver (range 1/3 mile). One thousand five channel nodes can communicate to one receiver (30 minute update). Current draw (sleep) is 20 microamps, allowing 5 year battery life w/one 3.6 volt Li-Ion AA size battery. The network nodes include sensor excitation (AC or DC), multiplexer, instrumentation amplifier, 16 bit A/D converter, microprocessor, and RF link. They are compatible with thermocouples, strain gauges, load/torque transducers, inductive/capacitive sensors. The receiver (418 MHz) includes a single board computer (SBC) with Ethernet capability, internet file transfer protocols (XML/HTML), and data storage. The receiver detects data from specific nodes, performs error checking, records the data. The web server interrogates the SBC (from Microsoft's Internet Explorer or Netscape's Navigator) to distribute data. This system can collect data from thousands of remote sensors on a smart structure, and be shared by an unlimited number of users.

``The Legal Bit's in Russian'': Making Sense of Downloaded Music

NASA Astrophysics Data System (ADS)

Kibby, Marjorie D.

Peer-to-peer sharing of music files grew in the face of consumer dissatisfaction with the compact disc and the absence of any real alternative. Many users were more or less “forced” to turn to illegal file sharing to access single tracks, back catalogues, and niche genres. Recently the almost simultaneous arrival of broadband internet and the iPod has seen music downloading become a respectable activity and a multi-billion dollar industry.

All-optical cryptography of M-QAM formats by using two-dimensional spectrally sliced keys.

PubMed

Abbade, Marcelo L F; Cvijetic, Milorad; Messani, Carlos A; Alves, Cleiton J; Tenenbaum, Stefan

2015-05-10

There has been an increased interest in enhancing the security of optical communications systems and networks. All-optical cryptography methods have been considered as an alternative to electronic data encryption. In this paper we propose and verify the use of a novel all-optical scheme based on cryptographic keys applied on the spectral signal for encryption of the M-QAM modulated data with bit rates of up to 200 gigabits per second.

A ROF transport system using phase & polarization modulation based on OFDM technique

NASA Astrophysics Data System (ADS)

Mallick, Khaleda; Patra, Ardhendu Sekhar

2018-05-01

A radio-over-fiber (ROF) transport system using phase and polarization modulator based on orthogonal frequency division multiplexing (OFDM) technique has been proposed and demonstrated, to transmit 2.5 Gbps at 7.5 GHz over 40 km single mode fiber (SMF). The transmission performance is observed by proper bit error rate and clear eye diagram. Our proposed system become a prominent alternative, as it has advantages of communication link for greater bandwidth and data rates.

A Concurrent Smalltalk Compiler for the Message-Driven Processor

DTIC Science & Technology

1988-05-01

apj with bits from low-bit (inclusive) to high-bit (exclusive) set. ;;;Low-bit defaults to zero. (defmacro brange (high-bit &optional low-bit) (list...n2) (null (cddr num))) (aetg bits (b+ bits (if (>- nl n2) ( brange (1+ nl) n2) ( brange (1+ n2) ni)))) (error "Bad bmap range: -S" flu.)))) (t (error...vlocs) flat ((vlive (b- finst-vllv* mast) *I.( brange firat-context-slot-nun))) (next (inst-next last))) (if (bempty vlive) (delete-module module inat

Effects of plastic bits on the condition and behaviour of captive-reared pheasants.

PubMed

Butler, D A; Davis, C

2010-03-27

Between 2005 and 2007, data were collected from game farms across England and Wales to examine the effects of the use of bits on the physiological condition and behaviour of pheasants. On each site, two pheasant pens kept in the same conditions were randomly allocated to either use bits or not. The behaviour and physiological conditions of pheasants in each treatment pen were assessed on the day of bitting and weekly thereafter until release. Detailed records of feed usage, medications and mortality were also kept. Bits halved the number of acts of bird-on-bird pecking, but they doubled the incidence of headshaking and scratching. Bits caused nostril inflammation and bill deformities in some birds, particularly after seven weeks of age. In all weeks after bitting, feather condition was poorer in non-bitted pheasants than in those fitted with bits. Less than 3 per cent of bitted birds had damaged skin, but in the non-bitted pens this figure increased over time to 23 per cent four weeks later. Feed use and mortality did not differ between bitted and non-bitted birds.

Programmable superpositions of Ising configurations

NASA Astrophysics Data System (ADS)

Sieberer, Lukas M.; Lechner, Wolfgang

2018-05-01

We present a framework to prepare superpositions of bit strings, i.e., many-body spin configurations, with deterministic programmable probabilities. The spin configurations are encoded in the degenerate ground states of the lattice-gauge representation of an all-to-all connected Ising spin glass. The ground-state manifold is invariant under variations of the gauge degrees of freedom, which take the form of four-body parity constraints. Our framework makes use of these degrees of freedom by individually tuning them to dynamically prepare programmable superpositions. The dynamics combines an adiabatic protocol with controlled diabatic transitions. We derive an effective model that allows one to determine the control parameters efficiently even for large system sizes.

Masking Quantum Information is Impossible

NASA Astrophysics Data System (ADS)

Modi, Kavan; Pati, Arun Kumar; SenDe, Aditi; Sen, Ujjwal

2018-06-01

Classical information encoded in composite quantum states can be completely hidden from the reduced subsystems and may be found only in the correlations. Can the same be true for quantum information? If quantum information is hidden from subsystems and spread over quantum correlation, we call it masking of quantum information. We show that while this may still be true for some restricted sets of nonorthogonal quantum states, it is not possible for arbitrary quantum states. This result suggests that quantum qubit commitment—a stronger version of the quantum bit commitment—is not possible in general. Our findings may have potential applications in secret sharing and future quantum communication protocols.

Quantum generalisation of feedforward neural networks

NASA Astrophysics Data System (ADS)

Wan, Kwok Ho; Dahlsten, Oscar; Kristjánsson, Hlér; Gardner, Robert; Kim, M. S.

2017-09-01

We propose a quantum generalisation of a classical neural network. The classical neurons are firstly rendered reversible by adding ancillary bits. Then they are generalised to being quantum reversible, i.e., unitary (the classical networks we generalise are called feedforward, and have step-function activation functions). The quantum network can be trained efficiently using gradient descent on a cost function to perform quantum generalisations of classical tasks. We demonstrate numerically that it can: (i) compress quantum states onto a minimal number of qubits, creating a quantum autoencoder, and (ii) discover quantum communication protocols such as teleportation. Our general recipe is theoretical and implementation-independent. The quantum neuron module can naturally be implemented photonically.

Quantum teleportation between distant matter qubits.

PubMed

Olmschenk, S; Matsukevich, D N; Maunz, P; Hayes, D; Duan, L-M; Monroe, C

2009-01-23

Quantum teleportation is the faithful transfer of quantum states between systems, relying on the prior establishment of entanglement and using only classical communication during the transmission. We report teleportation of quantum information between atomic quantum memories separated by about 1 meter. A quantum bit stored in a single trapped ytterbium ion (Yb+) is teleported to a second Yb+ atom with an average fidelity of 90% over a replete set of states. The teleportation protocol is based on the heralded entanglement of the atoms through interference and detection of photons emitted from each atom and guided through optical fibers. This scheme may be used for scalable quantum computation and quantum communication.

Hybrid quantum processors: molecular ensembles as quantum memory for solid state circuits.

PubMed

Rabl, P; DeMille, D; Doyle, J M; Lukin, M D; Schoelkopf, R J; Zoller, P

2006-07-21

We investigate a hybrid quantum circuit where ensembles of cold polar molecules serve as long-lived quantum memories and optical interfaces for solid state quantum processors. The quantum memory realized by collective spin states (ensemble qubit) is coupled to a high-Q stripline cavity via microwave Raman processes. We show that, for convenient trap-surface distances of a few microm, strong coupling between the cavity and ensemble qubit can be achieved. We discuss basic quantum information protocols, including a swap from the cavity photon bus to the molecular quantum memory, and a deterministic two qubit gate. Finally, we investigate coherence properties of molecular ensemble quantum bits.

A network architecture for International Business Satellite communications

NASA Astrophysics Data System (ADS)

Takahata, Fumio; Nohara, Mitsuo; Takeuchi, Yoshio

Demand Assignment (DA) control is expected to be introduced in the International Business Satellte communications (IBS) network in order to cope with a growing international business traffic. The paper discusses the DA/IBS network from the viewpoints of network configuration, satellite channel configuration and DA control. The network configuration proposed here consists of one Central Station with network management function and several Network Coordination Stations with user management function. A satellite channel configuration is also presented along with a tradeoff study on transmission bit rate, high power amplifier output power requirement, and service quality. The DA control flow and protocol based on CCITT Signalling System No. 7 are also proposed.

Experimental purification of single qubits.

PubMed

Ricci, M; De Martini, F; Cerf, N J; Filip, R; Fiurásek, J; Macchiavello, C

2004-10-22

We report the experimental realization of the purification protocol for single qubits sent through a depolarizing channel. The qubits are associated with polarization states of single photons and the protocol is achieved by means of passive linear optical elements. The present approach may represent a convenient alternative to the distillation and error correction protocols of quantum information.

Using Green Star Metrics to Optimize the Greenness of Literature Protocols for Syntheses

ERIC Educational Resources Information Center

Duarte, Rita C. C.; Ribeiro, M. Gabriela T. C.; Machado, Adélio A. S. C.

2015-01-01

A procedure to improve the greenness of a synthesis, without performing laboratory work, using alternative protocols available in the literature is presented. The greenness evaluation involves the separate assessment of the different steps described in the available protocols--reaction, isolation, and purification--as well as the global process,…

A 1000+ channel bionic communication system.

PubMed

Schulman, Joseph H; Mobley, J Phil; Wolfe, James; Stover, Howard; Krag, Adrian

2006-01-01

The wireless electronic nervous system interface known as the functional electrical stimulation-battery powered bion system is being developed at the Alfred Mann Foundation. It contains a real-time propagated wave micro-powered multichannel communication system. This system is designed to send bi-directional messages between an external master controller unit (MCU), and each one of a group of injectable stimulator-sensor battery powered bion implants (BPB). The system is capable of communicating in each direction about 90 times per second using a structure of 850 time slots within a repeating 11 millisecond time window. The system's total Time Division Multiple Access (TDMA) communication capability is about 77,000 two-way communications per second on a single 5 MHz wide radio channel. Each time slot can be used by one BPB, or shared alternately by two or more BPBs. Each bidirectional communication consists of a 15 data bit message sent from the MCU sequentially to each BPB and 10 data bit message sent sequentially from each BPB to the MCU. Redundancy bits are included to provide error detection and correction. This communication system is designed to draw only a few microamps from the 3.6 volt, 3.0 mAHr lithium ion (LiIon) battery contained in each BPB, and the majority of the communications circuitry is contained within a 1.4x5 mm integrated circuit.

Evaluate the Feasibility of Using Frontal SSVEP to Implement an SSVEP-Based BCI in Young, Elderly and ALS Groups.

PubMed

Hsu, Hao-Teng; Lee, I-Hui; Tsai, Han-Ting; Chang, Hsiang-Chih; Shyu, Kuo-Kai; Hsu, Chuan-Chih; Chang, Hsiao-Huang; Yeh, Ting-Kuang; Chang, Chun-Yen; Lee, Po-Lei

2016-05-01

This paper studies the amplitude-frequency characteristic of frontal steady-state visual evoked potential (SSVEP) and its feasibility as a control signal for brain computer interface (BCI). SSVEPs induced by different stimulation frequencies, from 13 ~ 31 Hz in 2 Hz steps, were measured in eight young subjects, eight elders and seven ALS patients. Each subject was requested to participate in a calibration study and an application study. The calibration study was designed to find the amplitude-frequency characteristics of SSVEPs recorded from Oz and Fpz positions, while the application study was designed to test the feasibility of using frontal SSVEP to control a two-command SSVEP-based BCI. The SSVEP amplitude was detected by an epoch-average process which enables artifact-contaminated epochs can be removed. The seven ALS patients were severely impaired, and four patients, who were incapable of completing our BCI task, were excluded from calculation of BCI performance. The averaged accuracies, command transfer intervals and information transfer rates in operating frontal SSVEP-based BCI were 96.1%, 3.43 s/command, and 14.42 bits/min in young subjects; 91.8%, 6.22 s/command, and 6.16 bits/min in elders; 81.2%, 12.14 s/command, and 1.51 bits/min in ALS patients, respectively. The frontal SSVEP could be an alternative choice to design SSVEP-based BCI.

Private States, Quantum Data Hiding, and the Swapping of Perfect Secrecy.

PubMed

Christandl, Matthias; Ferrara, Roberto

2017-12-01

An important contribution to the understanding of quantum key distribution has been the discovery of entangled states from which secret bits, but no maximally entangled states, can be extracted [Horodecki et al., Phys. Rev. Lett. 94, 200501 (2005)PRLTAO0031-900710.1103/PhysRevLett.94.200501]. The construction of those states was based on an intuition that the quantum mechanical phenomena of data hiding and privacy might be related. In this Letter we firmly connect these two phenomena and highlight three aspects of this result. First, we simplify the definition of the secret key rate. Second, we give a formula for the one-way distillable entanglement of certain private states. Third, we consider the problem of extending the distance of quantum key distribution with help of intermediate stations, a setting called the quantum key repeater. We show that for protocols that first distill private states, it is essentially optimal to use the standard quantum repeater protocol based on entanglement distillation and entanglement swapping.

Usefulness of multiqubit W-type states in quantum information processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, P.; Adhikari, S.; Kumar, A., E-mail: atulk@iitj.ac.in

We analyze the efficiency of multiqubit W-type states as resources for quantum information. For this, we identify and generalize four-qubit W-type states. Our results show that these states can be used as resources for deterministic quantum information processing. The utility of results, however, is limited by the availability of experimental setups to perform and distinguish multiqubit measurements. We therefore emphasize protocols where two users want to establish an optimal bipartite entanglement using the partially entangled W-type states. We find that for such practical purposes, four-qubit W-type states can be a better resource in comparison to three-qubit W-type states. For amore » dense coding protocol, our states can be used deterministically to send two bits of classical message by locally manipulating a single qubit. In addition, we also propose a realistic experimental method to prepare the four-qubit W-type states using standard unitary operations and weak measurements.« less

Compression and Transmission of RF Signals for Telediagnosis

NASA Astrophysics Data System (ADS)

Seko, Toshihiro; Doi, Motonori; Oshiro, Osamu; Chihara, Kunihiro

2000-05-01

Health care is a critical issue nowadays. Much emphasis is given to quality care for all people. Telediagnosis has attracted public attention. We propose a new method of ultrasound image transmission for telediagnosis. In conventional methods, video image signals are transmitted. In our method, the RF signals which are acquired by an ultrasound probe, are transmitted. The RF signals can be transformed to color Doppler images or high-resolution images by a receiver. Because a stored form is adopted, the proposed system can be realized with existent technology such as hyper text transfer protocol (HTTP) and file transfer protocol (FTP). In this paper, we describe two lossless compression methods which specialize in the transmission of RF signals. One of the methods uses the characteristics of the RF signal. In the other method, the amount of the data is reduced. Measurements were performed in water targeting an iron block and triangular Styrofoam. Additionally, abdominal fat measurement was performed. Our method achieved a compression rate of 13% with 8 bit data.

Unforgeable noise-tolerant quantum tokens

PubMed Central

Pastawski, Fernando; Yao, Norman Y.; Jiang, Liang; Lukin, Mikhail D.; Cirac, J. Ignacio

2012-01-01

The realization of devices that harness the laws of quantum mechanics represents an exciting challenge at the interface of modern technology and fundamental science. An exemplary paragon of the power of such quantum primitives is the concept of “quantum money” [Wiesner S (1983) ACM SIGACT News 15:78–88]. A dishonest holder of a quantum bank note will invariably fail in any counterfeiting attempts; indeed, under assumptions of ideal measurements and decoherence-free memories such security is guaranteed by the no-cloning theorem. In any practical situation, however, noise, decoherence, and operational imperfections abound. Thus, the development of secure “quantum money”-type primitives capable of tolerating realistic infidelities is of both practical and fundamental importance. Here, we propose a novel class of such protocols and demonstrate their tolerance to noise; moreover, we prove their rigorous security by determining tight fidelity thresholds. Our proposed protocols require only the ability to prepare, store, and measure single quantum bit memories, making their experimental realization accessible with current technologies.

Private States, Quantum Data Hiding, and the Swapping of Perfect Secrecy

NASA Astrophysics Data System (ADS)

Christandl, Matthias; Ferrara, Roberto

2017-12-01

An important contribution to the understanding of quantum key distribution has been the discovery of entangled states from which secret bits, but no maximally entangled states, can be extracted [Horodecki et al., Phys. Rev. Lett. 94, 200501 (2005), 10.1103/PhysRevLett.94.200501]. The construction of those states was based on an intuition that the quantum mechanical phenomena of data hiding and privacy might be related. In this Letter we firmly connect these two phenomena and highlight three aspects of this result. First, we simplify the definition of the secret key rate. Second, we give a formula for the one-way distillable entanglement of certain private states. Third, we consider the problem of extending the distance of quantum key distribution with help of intermediate stations, a setting called the quantum key repeater. We show that for protocols that first distill private states, it is essentially optimal to use the standard quantum repeater protocol based on entanglement distillation and entanglement swapping.

Practical secure quantum communications

NASA Astrophysics Data System (ADS)

Diamanti, Eleni

2015-05-01

We review recent advances in the field of quantum cryptography, focusing in particular on practical implementations of two central protocols for quantum network applications, namely key distribution and coin flipping. The former allows two parties to share secret messages with information-theoretic security, even in the presence of a malicious eavesdropper in the communication channel, which is impossible with classical resources alone. The latter enables two distrustful parties to agree on a random bit, again with information-theoretic security, and with a cheating probability lower than the one that can be reached in a classical scenario. Our implementations rely on continuous-variable technology for quantum key distribution and on a plug and play discrete-variable system for coin flipping, and necessitate a rigorous security analysis adapted to the experimental schemes and their imperfections. In both cases, we demonstrate the protocols with provable security over record long distances in optical fibers and assess the performance of our systems as well as their limitations. The reported advances offer a powerful toolbox for practical applications of secure communications within future quantum networks.

Southern blotting.

PubMed

Brown, T

2001-05-01

Southern blotting is the transfer of DNA fragments from an electrophoresis gel to a membrane support (the properties and advantages of the different types of membrane, transfer buffer, and transfer method are discussed in detail), resulting in immobilization of the DNA fragments, so the membrane carries a semipermanent reproduction of the banding pattern of the gel. After immobilization, the DNA can be subjected to hybridization analysis, enabling bands with sequence similarity to a labeled probe to be identified. This appendix describes Southern blotting via upward capillary transfer of DNA from an agarose gel onto a nylon or nitrocellulose membrane, using a high-salt transfer buffer to promote binding of DNA to the membrane. With the high-salt buffer, the DNA becomes bound to the membrane during transfer but not permanently immobilized. Immobilization is achieved by UV irradiation (for nylon) or baking (for nitrocellulose). A Support Protocol describes how to calibrate a UV transilluminator for optimal UV irradiation of a nylon membrane. An alternate protocol details transfer using nylon membranes and an alkaline buffer, and is primarily used with positively charged nylon membranes. The advantage of this combination is that no post-transfer immobilization step is required, as the positively charged membrane binds DNA irreversibly under alkaline transfer conditions. The method can also be used with neutral nylon membranes but less DNA will be retained. A second alternate protocol describes a transfer method based on a different transfer-stack setup. The traditional method of upward capillary transfer of DNA from gel to membrane described in the first basic and alternate protocols has certain disadvantages, notably the fact that the gel can become crushed by the weighted filter papers and paper towels that are laid on top of it. This slows down the blotting process and may reduce the amount of DNA that can be transferred. The downward capillary method described in the second alternate protocol is therefore more rapid than the basic protocol and can result in more complete transfer. Although the ease and reliability of capillary transfer methods makes this far and away the most popular system for Southern blotting with agarose gels, it unfortunately does not work with polyacrylamide gels, whose smaller pore size impedes the transverse movement of the DNA molecules. The third alternate protocol describes an electroblotting procedure that is currently the most reliable method for transfer of DNA from a polyacrylamide gel. Dot and slot blotting are also described.

Bit-1 is an essential regulator of myogenic differentiation

PubMed Central

Griffiths, Genevieve S.; Doe, Jinger; Jijiwa, Mayumi; Van Ry, Pam; Cruz, Vivian; de la Vega, Michelle; Ramos, Joe W.; Burkin, Dean J.; Matter, Michelle L.

2015-01-01

Muscle differentiation requires a complex signaling cascade that leads to the production of multinucleated myofibers. Genes regulating the intrinsic mitochondrial apoptotic pathway also function in controlling cell differentiation. How such signaling pathways are regulated during differentiation is not fully understood. Bit-1 (also known as PTRH2) mutations in humans cause infantile-onset multisystem disease with muscle weakness. We demonstrate here that Bit-1 controls skeletal myogenesis through a caspase-mediated signaling pathway. Bit-1-null mice exhibit a myopathy with hypotrophic myofibers. Bit-1-null myoblasts prematurely express muscle-specific proteins. Similarly, knockdown of Bit-1 expression in C2C12 myoblasts promotes early differentiation, whereas overexpression delays differentiation. In wild-type mice, Bit-1 levels increase during differentiation. Bit-1-null myoblasts exhibited increased levels of caspase 9 and caspase 3 without increased apoptosis. Bit-1 re-expression partially rescued differentiation. In Bit-1-null muscle, Bcl-2 levels are reduced, suggesting that Bcl-2-mediated inhibition of caspase 9 and caspase 3 is decreased. Bcl-2 re-expression rescued Bit-1-mediated early differentiation in Bit-1-null myoblasts and C2C12 cells with knockdown of Bit-1 expression. These results support an unanticipated yet essential role for Bit-1 in controlling myogenesis through regulation of Bcl-2. PMID:25770104

High-speed phosphor-LED wireless communication system utilizing no blue filter

NASA Astrophysics Data System (ADS)

Yeh, C. H.; Chow, C. W.; Chen, H. Y.; Chen, J.; Liu, Y. L.; Wu, Y. F.

2014-09-01

In this paper, we propose and investigate an adaptively 84.44 to 190 Mb/s phosphor-LED visible light communication (VLC) system at a practical transmission distance. Here, we utilize the orthogonal-frequency-division-multiplexing quadrature-amplitude-modulation (OFDM-QAM) modulation with power/bit-loading algorithm in proposed VLC system. In the experiment, the optimal analogy pre-equalization design is also performed at LED-Tx side and no blue filter is used at the Rx side for extending the modulation bandwidth from 1 MHz to 30 MHz. In addition, the corresponding free space transmission lengths are between 75 cm and 2 m under various data rates of proposed VLC. And the measured bit error rates (BERs) of < 3.8×10-3 [forward error correction (FEC) limit] at different transmission lengths and measured data rates can be also obtained. Finally, we believe that our proposed scheme could be another alternative VLC implementation in practical distance, supporting < 100 Mb/s, using commercially available LED and PD (without optical blue filtering) and compact size.

Delay and Disruption Tolerant Networking MACHETE Model

NASA Technical Reports Server (NTRS)

Segui, John S.; Jennings, Esther H.; Gao, Jay L.

2011-01-01

To verify satisfaction of communication requirements imposed by unique missions, as early as 2000, the Communications Networking Group at the Jet Propulsion Laboratory (JPL) saw the need for an environment to support interplanetary communication protocol design, validation, and characterization. JPL's Multi-mission Advanced Communications Hybrid Environment for Test and Evaluation (MACHETE), described in Simulator of Space Communication Networks (NPO-41373) NASA Tech Briefs, Vol. 29, No. 8 (August 2005), p. 44, combines various commercial, non-commercial, and in-house custom tools for simulation and performance analysis of space networks. The MACHETE environment supports orbital analysis, link budget analysis, communications network simulations, and hardware-in-the-loop testing. As NASA is expanding its Space Communications and Navigation (SCaN) capabilities to support planned and future missions, building infrastructure to maintain services and developing enabling technologies, an important and broader role is seen for MACHETE in design-phase evaluation of future SCaN architectures. To support evaluation of the developing Delay Tolerant Networking (DTN) field and its applicability for space networks, JPL developed MACHETE models for DTN Bundle Protocol (BP) and Licklider/Long-haul Transmission Protocol (LTP). DTN is an Internet Research Task Force (IRTF) architecture providing communication in and/or through highly stressed networking environments such as space exploration and battlefield networks. Stressed networking environments include those with intermittent (predictable and unknown) connectivity, large and/or variable delays, and high bit error rates. To provide its services over existing domain specific protocols, the DTN protocols reside at the application layer of the TCP/IP stack, forming a store-and-forward overlay network. The key capabilities of the Bundle Protocol include custody-based reliability, the ability to cope with intermittent connectivity, the ability to take advantage of scheduled and opportunistic connectivity, and late binding of names to addresses.

Improved Iris Recognition through Fusion of Hamming Distance and Fragile Bit Distance.

PubMed

Hollingsworth, Karen P; Bowyer, Kevin W; Flynn, Patrick J

2011-12-01

The most common iris biometric algorithm represents the texture of an iris using a binary iris code. Not all bits in an iris code are equally consistent. A bit is deemed fragile if its value changes across iris codes created from different images of the same iris. Previous research has shown that iris recognition performance can be improved by masking these fragile bits. Rather than ignoring fragile bits completely, we consider what beneficial information can be obtained from the fragile bits. We find that the locations of fragile bits tend to be consistent across different iris codes of the same eye. We present a metric, called the fragile bit distance, which quantitatively measures the coincidence of the fragile bit patterns in two iris codes. We find that score fusion of fragile bit distance and Hamming distance works better for recognition than Hamming distance alone. To our knowledge, this is the first and only work to use the coincidence of fragile bit locations to improve the accuracy of matches.

Comparison of test protocols for standard room/corner tests

Treesearch

R. H. White; M. A. Dietenberger; H. Tran; O. Grexa; L. Richardson; K. Sumathipala; M. Janssens

1998-01-01

As part of international efforts to evaluate alternative reaction-to-fire tests, several series of room/comer tests have been conducted. This paper reviews the overall results of related projects in which different test protocols for standard room/corner tests were used. Differences in the test protocols involved two options for the ignition burner scenario and whether...

BIT BY BIT: A Game Simulating Natural Language Processing in Computers

ERIC Educational Resources Information Center

Kato, Taichi; Arakawa, Chuichi

2008-01-01

BIT BY BIT is an encryption game that is designed to improve students' understanding of natural language processing in computers. Participants encode clear words into binary code using an encryption key and exchange them in the game. BIT BY BIT enables participants who do not understand the concept of binary numbers to perform the process of…

IONAC-Lite

NASA Technical Reports Server (NTRS)

Torgerson, Jordan L.; Clare, Loren P.; Pang, Jackson

2011-01-01

The Interplanetary Overlay Net - working Protocol Accelerator (IONAC) described previously in The Inter - planetary Overlay Networking Protocol Accelerator (NPO-45584), NASA Tech Briefs, Vol. 32, No. 10, (October 2008) p. 106 (http://www.techbriefs.com/component/ content/article/3317) provides functions that implement the Delay Tolerant Networking (DTN) bundle protocol. New missions that require high-speed downlink-only use of DTN can now be accommodated by the unidirectional IONAC-Lite to support high data rate downlink mission applications. Due to constrained energy resources, a conventional software implementation of the DTN protocol can provide only limited throughput for any given reasonable energy consumption rate. The IONAC-Lite DTN Protocol Accelerator is able to reduce this energy consumption by an order of magnitude and increase the throughput capability by two orders of magnitude. In addition, a conventional DTN implementation requires a bundle database with a considerable storage requirement. In very high downlink datarate missions such as near-Earth radar science missions, the storage space utilization needs to be maximized for science data and minimized for communications protocol-related storage needs. The IONAC-Lite DTN Protocol Accelerator is implemented in a reconfigurable hardware device to accomplish exactly what s needed for high-throughput DTN downlink-only scenarios. The following are salient features of the IONAC-Lite implementation: An implementation of the Bundle Protocol for an environment that requires a very high rate bundle egress data rate. The C&DH (command and data handling) subsystem is also expected to be very constrained so the interaction with the C&DH processor and the temporary storage are minimized. Fully pipelined design so that bundle processing database is not required. Implements a lookup table-based approach to eliminate multi-pass processing requirement imposed by the Bundle Protocol header s length field structure and the SDNV (self-delimiting numeric value) data field formatting. 8-bit parallel datapath to support high data-rate missions. Reduced resource utilization implementation for missions that do not require custody transfer features. There was no known implementation of the DTN protocol in a field programmable gate array (FPGA) device prior to the current implementation. The combination of energy and performance optimization that embodies this design makes the work novel.

Evaluation of effectiveness of Er,Cr:YSGG laser for root canal disinfection: theoretical simulation of temperature elevations in root dentin.

PubMed

Zhu, L; Tolba, M; Arola, D; Salloum, M; Meza, F

2009-07-01

Erbium, chromium: yttrium, scandium, gallium, garnet (Er,Cr:YSGG) lasers are currently being investigated for disinfecting the root canal system. Prior to using laser therapy, it is important to understand the temperature distribution and to assess thermal damage to the surrounding tissue. In this study, a theoretical simulation using the Pennes bioheat equation is conducted to evaluate how heat spreads from the canal surface using an Er,Cr:YSGG laser. Results of the investigation show that some of the proposed treatment protocols for killing bacteria in the deep dentin are ineffective, even for long heating durations. Based on the simulation, an alternative treatment protocol is identified that has improved effectiveness and is less likely to introduce collateral damage to the surrounding tissue. The alternative protocol uses 350 mW laser power with repeating laser tip movement to achieve bacterial disinfection in the deep dentin (800 microm lateral from the canal surface), while avoiding thermal damage to the surrounding tissue (T<47 degrees C). The alternative treatment protocol has the potential to not only achieve bacterial disinfection of deep dentin but also shorten the treatment time, thereby minimizing potential patient discomfort during laser procedures.

Bit selection using field drilling data and mathematical investigation

NASA Astrophysics Data System (ADS)

Momeni, M. S.; Ridha, S.; Hosseini, S. J.; Meyghani, B.; Emamian, S. S.

2018-03-01

A drilling process will not be complete without the usage of a drill bit. Therefore, bit selection is considered to be an important task in drilling optimization process. To select a bit is considered as an important issue in planning and designing a well. This is simply because the cost of drilling bit in total cost is quite high. Thus, to perform this task, aback propagation ANN Model is developed. This is done by training the model using several wells and it is done by the usage of drilling bit records from offset wells. In this project, two models are developed by the usage of the ANN. One is to find predicted IADC bit code and one is to find Predicted ROP. Stage 1 was to find the IADC bit code by using all the given filed data. The output is the Targeted IADC bit code. Stage 2 was to find the Predicted ROP values using the gained IADC bit code in Stage 1. Next is Stage 3 where the Predicted ROP value is used back again in the data set to gain Predicted IADC bit code value. The output is the Predicted IADC bit code. Thus, at the end, there are two models that give the Predicted ROP values and Predicted IADC bit code values.

Investigation of PDC bit failure base on stick-slip vibration analysis of drilling string system plus drill bit

NASA Astrophysics Data System (ADS)

Huang, Zhiqiang; Xie, Dou; Xie, Bing; Zhang, Wenlin; Zhang, Fuxiao; He, Lei

2018-03-01

The undesired stick-slip vibration is the main source of PDC bit failure, such as tooth fracture and tooth loss. So, the study of PDC bit failure base on stick-slip vibration analysis is crucial to prolonging the service life of PDC bit and improving ROP (rate of penetration). For this purpose, a piecewise-smooth torsional model with 4-DOF (degree of freedom) of drilling string system plus PDC bit is proposed to simulate non-impact drilling. In this model, both the friction and cutting behaviors of PDC bit are innovatively introduced. The results reveal that PDC bit is easier to fail than other drilling tools due to the severer stick-slip vibration. Moreover, reducing WOB (weight on bit) and improving driving torque can effectively mitigate the stick-slip vibration of PDC bit. Therefore, PDC bit failure can be alleviated by optimizing drilling parameters. In addition, a new 4-DOF torsional model is established to simulate torsional impact drilling and the effect of torsional impact on PDC bit's stick-slip vibration is analyzed by use of an engineering example. It can be concluded that torsional impact can mitigate stick-slip vibration, prolonging the service life of PDC bit and improving drilling efficiency, which is consistent with the field experiment results.

Growth on solid media.

PubMed

Elbing, Karen; Brent, Roger

2002-08-01

Detailed protocols are provided for titering and isolating bacterial colonies by serial dilutions, or alternatively by streaking or spreading a plate. Support protocols describe replica plating as well as methods for storing strains as agar stabs or frozen glycerol stocks.

Cost-effectiveness comparison between pituitary down-regulation with a gonadotropin-releasing hormone agonist short regimen on alternate days and an antagonist protocol for assisted fertilization treatments.

PubMed

Maldonado, Luiz Guilherme Louzada; Franco, José Gonçalves; Setti, Amanda Souza; Iaconelli, Assumpto; Borges, Edson

2013-05-01

To compare cost-effectiveness between pituitary down-regulation with a GnRH agonist (GnRHa) short regimen on alternate days and GnRH antagonist (GnRHant) multidose protocol on in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) outcome. Prospective, randomized. A private center. Patients were randomized into GnRHa (n = 48) and GnRHant (n = 48) groups. GnRHa stimulation protocol: administration of triptorelin on alternate days starting on the first day of the cycle, recombinant FSH (rFSH), and recombinant hCG (rhCG) microdose. GnRHant protocol: administration of a daily dose of rFSH, cetrorelix, and rhCG microdose. ICSI outcomes and treatment costs. A significantly lower number of patients underwent embryo transfer in the GnRHa group. Clinical pregnancy rate was significantly lower and miscarriage rate was significantly higher in the GnRHa group. It was observed a significant lower cost per cycle in the GnRHa group compared with the GnRHant group ($5,327.80 ± 387.30 vs. $5,900.40 ± 472.50). However, mean cost per pregnancy in the GnRHa was higher than in the GnRHant group ($19,671.80 ± 1,430.00 vs. $11,328.70 ± 907.20). Although the short controlled ovarian stimulation protocol with GnRHa on alternate days, rFSH, and rhCG microdose may lower the cost of an individual IVF cycle, it requires more cycles to achieve pregnancy. NCT01468441. Copyright © 2013 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Boring apparatus capable of boring straight holes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peterson, C.R.

The invention relates to a rock boring assembly for producing a straight hole for use in a drill string above a pilot boring bit of predetermined diameter smaller than the desired final hole size. The boring assembly comprises a small conical boring bit and a larger conical boring, the conical boring bits mounted on lower and upper ends of an enlongated spacer, respectively, and the major effective cutting diameters of each of the conical boring bits being at least 10% greater than the minor effective cutting diameter of the respective bit. The spacer has a cross-section resistant bending and spacesmore » the conical boring bits apart a distance at least 5 times the major cutting diameter of the small conical boring bit, thereby spacing the pivot points provided by the two conical boring bits to limit bodily angular deflection of the assembly and providing a substantial moment arm to resist lateral forces applied to the assembly by the pilot bit and drill string. The spacing between the conical bits is less than about 20 times the major cutting diameter of the lower conical boring bit to enable the spacer to act as a bend-resistant beam to resist angular deflection of the axis of either of the conical boring bits relative to the other when it receives uneven lateral force due to non-uniformity of cutting conditions about the circumference of the bit. Advantageously the boring bits also are self-advancing and feature skewed rollers. 7 claims.« less

Bit-Grooming: Shave Your Bits with Razor-sharp Precision

NASA Astrophysics Data System (ADS)

Zender, C. S.; Silver, J.

2017-12-01

Lossless compression can reduce climate data storage by 30-40%. Further reduction requires lossy compression that also reduces precision. Fortunately, geoscientific models and measurements generate false precision (scientifically meaningless data bits) that can be eliminated without sacrificing scientifically meaningful data. We introduce Bit Grooming, a lossy compression algorithm that removes the bloat due to false-precision, those bits and bytes beyond the meaningful precision of the data.Bit Grooming is statistically unbiased, applies to all floating point numbers, and is easy to use. Bit-Grooming reduces geoscience data storage requirements by 40-80%. We compared Bit Grooming to competitors Linear Packing, Layer Packing, and GRIB2/JPEG2000. The other compression methods have the edge in terms of compression, but Bit Grooming is the most accurate and certainly the most usable and portable.Bit Grooming provides flexible and well-balanced solutions to the trade-offs among compression, accuracy, and usability required by lossy compression. Geoscientists could reduce their long term storage costs, and show leadership in the elimination of false precision, by adopting Bit Grooming.

A Compression Algorithm for Field Programmable Gate Arrays in the Space Environment

DTIC Science & Technology

2011-12-01

Bit 1 ,Bit 0P  . (V.3) Equation (V.3) is implemented with a string of XOR gates and Bit Basher blocks, as shown in Figure 31. As discussed in...5], the string of Bit Basher blocks are used to separate each 35-bit value into 35 one-bit values, and the string of XOR gates is used to

Drag bit construction

DOEpatents

Hood, M.

1986-02-11

A mounting movable with respect to an adjacent hard face has a projecting drag bit adapted to engage the hard face. The drag bit is disposed for movement relative to the mounting by encounter of the drag bit with the hard face. That relative movement regulates a valve in a water passageway, preferably extending through the drag bit, to play a stream of water in the area of contact of the drag bit and the hard face and to prevent such water play when the drag bit is out of contact with the hard face. 4 figs.

Drag bit construction

DOEpatents

Hood, Michael

1986-01-01

A mounting movable with respect to an adjacent hard face has a projecting drag bit adapted to engage the hard face. The drag bit is disposed for movement relative to the mounting by encounter of the drag bit with the hard face. That relative movement regulates a valve in a water passageway, preferably extending through the drag bit, to play a stream of water in the area of contact of the drag bit and the hard face and to prevent such water play when the drag bit is out of contact with the hard face.

The Dutch complementary and alternative medicine (CAM) protocol: to ensure the safe and effective use of complementary and alternative medicine within Dutch mental health care.

PubMed

Hoenders, H J Rogier; Appelo, Martin T; van den Brink, Erik H; Hartogs, Bregje M A; de Jong, Joop T V M

2011-12-01

Complementary and alternative medicine (CAM) is subject to heated debates and prejudices. Studies show that CAM is widely used by psychiatric patients, usually without the guidance of a therapist and without the use of a solid working method, leading to potential health risks. The purpose of this study is to facilitate the judicious use of CAM alongside conventional psychiatry in an outpatient psychiatric clinic. A search was made through scientific and legal articles and discussion in focus groups. In the Centre for Integrative Psychiatry (CIP) of Lentis in The Netherlands, some carefully selected CAM are offered under strict conditions, alongside conventional treatments. Because of the controversy and the potential health risks, Lentis designed a protocol that is presented. The CIP hopes, by using this protocol, to better serve and respect the individual needs and preferences of the diversity of psychiatric patients in our Dutch multicultural society, and better protect them from harm.

Method of Performance-Aware Security of Unicast Communication in Hybrid Satellite Networks

NASA Technical Reports Server (NTRS)

Baras, John S. (Inventor); Roy-Chowdhury, Ayan (Inventor)

2014-01-01

A method and apparatus utilizes Layered IPSEC (LES) protocol as an alternative to IPSEC for network-layer security including a modification to the Internet Key Exchange protocol. For application-level security of web browsing with acceptable end-to-end delay, the Dual-mode SSL protocol (DSSL) is used instead of SSL. The LES and DSSL protocols achieve desired end-to-end communication security while allowing the TCP and HTTP proxy servers to function correctly.

Flight related tuberculosis contact investigations in the United States: comparative risk and economic analysis of alternate protocols.

PubMed

Marienau, Karen J; Cramer, Elaine H; Coleman, Margaret S; Marano, Nina; Cetron, Martin S

2014-01-01

In-flight transmission risk of Mycobacterium tuberculosis is not well defined, although studies suggest it is low. The impact of flight-related tuberculosis (TB) contact investigations (TBCIs) on TB prevention and control is not well established, and they compete for resources with activities with established benefits. We sought to determine the risks and cost-benefits of using more restrictive criteria in comparison to the Centers for Disease Control and Prevention (CDC) 2008 protocol for TBCIs. The risk-benefits of a modified CDC protocol were analyzed in comparison to the 2008 CDC protocol using data from flight-related TBCIs conducted in the United States from 2007 through 2009. We predicted the numbers and characteristics of case-travelers that would be identified using each protocol's criteria, and results of the associated passenger-contacts' TB screening tests. The economic analysis compared the costs of TBCIs to avoided costs of TB treatment and mortality using a Return on Investment model. The estimated in-flight transmission risk using a modified CDC protocol was 1.4%-19% versus 1.1%-24% for the 2008 protocol. Numbers of TBCIs and immediate costs to health departments were reduced by half. Long-term cost-benefits were comparable. CDC's modified protocol appears to be a feasible alternative that will conserve public health resources without jeopardizing the public's health. Published by Elsevier Ltd.

Effectiveness of oxaliplatin desensitization protocols.

PubMed

Cortijo-Cascajares, Susana; Nacle-López, Inmaculada; García-Escobar, Ignacio; Aguilella-Vizcaíno, María José; Herreros-de-Tejada, Alberto; Cortés-Funes Castro, Hernán; Calleja-Hernández, Miguel-Ángel

2013-03-01

Hypersensitivity reaction (HSR) to antineoplastic drugs can force doctors to stop treatment and seek other alternatives. These alternatives may be less effective, not as well tolerated and/or more expensive. Another option is to use desensitization protocols that induce a temporary state of tolerance by gradually administering small quantities of the antineoplastic drug until the therapeutic dosage is reached. The aim of this study is to assess the effectiveness of oxaliplatin desensitization protocols. A retrospective observational study was carried out between January 2006 and May 2011. The inclusion criteria were patients undergoing chemotherapy treatment with oxaliplatin who had developed an HSR to the drug and who were candidates for continuing the treatment using a desensitization protocol. The patients' clinical records were reviewed and variables were gathered relating to the patient, the treatment, the HSR, and the desensitization protocol administered. The data were analysed using version 18.0 of the statistics program SPSS. A total of 53 desensitization protocols were administered to 21 patients. In 89 % of these cases, no new reactions occurred while the drug was being administered. New reactions of mild severity only occurred in 11 % of cases, and none of these reactions were severe enough for treatment to be stopped. All patients were able to complete the desensitization protocol. This study confirms that oxaliplatin desensitization protocols are safe and effective and allow patients to continue with the treatment that initially caused an HSR.

Protocols for Late Maxillary Protraction in Cleft Lip and Palate Patients at Childrens Hospital Los Angeles

PubMed Central

Yen, Stephen L-K

2011-01-01

This paper describes the protocols used at Childrens Hospital Los Angeles (CHLA) to protract the maxilla during early adolescence. It is a modification of techniques introduced by Eric Liou with his Alternate Rapid Maxillary Expansion and Constriction (ALT-RAMEC) technique. The main differences between the CHLA protocol and previous maxillary protraction protocols are the age the protraction is attempted, the sutural loosening by alternating weekly expansion with constriction and the use of Class III elastics to support and redirect the protraction by nightly facemask wear. The CHLA protocol entirely depends on patient compliance and must be carefully taught and monitored. In a cooperative patient, the technique can correct a Class III malocclusion that previously would have been treated with LeFort 1 maxillary advancement surgery. Thus, it is not appropriate for patients requiring 2 jaw surgeries to correct mandibular prognathism, occlusal cants or facial asymmetry. The maxillary protraction appears to work by a combination of skeletal advancement, dental compensation and rotation of the occlusal planes. Microscrew/microimplant/temporary anchorage devices have been used with these maxillary protraction protocols to assist in expanding the maxilla, increasing skeletal anchorage during protraction, limiting dental compensations and reducing skeletal relapse. PMID:21765629

PDC-bit performance under simulated borehole conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, E.E.; Azar, J.J.

1993-09-01

Laboratory drilling tests were used to investigate the effects of pressure on polycrystalline-diamond-compact (PDC) drill-bit performance. Catoosa shale core samples were drilled with PDC and roller-cone bits at up to 1,750-psi confining pressure. All tests were conducted in a controlled environment with a full-scale laboratory drilling system. Test results indicate, that under similar operating conditions, increases in confining pressure reduce PDC-bit performance as much as or more than conventional-rock-bit performance. Specific energy calculations indicate that a combination of rock strength, chip hold-down, and bit balling may have reduced performance. Quantifying the degree to which pressure reduces PDC-bit performance will helpmore » researchers interpret test results and improve bit designs and will help drilling engineers run PDC bits more effectively in the field.« less

Smart built-in test

NASA Technical Reports Server (NTRS)

Richards, Dale W.

1990-01-01

The work which built-in test (BIT) is asked to perform in today's electronic systems increases with every insertion of new technology or introduction of tighter performance criteria. Yet the basic purpose remains unchanged -- to determine with high confidence the operational capability of that equipment. Achievement of this level of BIT performance requires the management and assimilation of a large amount of data, both realtime and historical. Smart BIT has taken advantage of advanced techniques from the field of artificial intelligence (AI) in order to meet these demands. The Smart BIT approach enhances traditional functional BIT by utilizing AI techniques to incorporate environmental stress data, temporal BIT information and maintenance data, and realtime BIT reports into an integrated test methodology for increased BIT effectiveness and confidence levels. Future research in this area will incorporate onboard fault-logging of BIT output, stress data and Smart BIT decision criteria in support of a singular, integrated and complete test and maintenance capability. The state of this research is described along with a discussion of directions for future development.

Smart built-in test

NASA Astrophysics Data System (ADS)

Richards, Dale W.

1990-03-01

The work which built-in test (BIT) is asked to perform in today's electronic systems increases with every insertion of new technology or introduction of tighter performance criteria. Yet the basic purpose remains unchanged -- to determine with high confidence the operational capability of that equipment. Achievement of this level of BIT performance requires the management and assimilation of a large amount of data, both realtime and historical. Smart BIT has taken advantage of advanced techniques from the field of artificial intelligence (AI) in order to meet these demands. The Smart BIT approach enhances traditional functional BIT by utilizing AI techniques to incorporate environmental stress data, temporal BIT information and maintenance data, and realtime BIT reports into an integrated test methodology for increased BIT effectiveness and confidence levels. Future research in this area will incorporate onboard fault-logging of BIT output, stress data and Smart BIT decision criteria in support of a singular, integrated and complete test and maintenance capability. The state of this research is described along with a discussion of directions for future development.

Mobile Monitoring and Embedded Control System for Factory Environment

PubMed Central

Lian, Kuang-Yow; Hsiao, Sung-Jung; Sung, Wen-Tsai

2013-01-01

This paper proposes a real-time method to carry out the monitoring of factory zone temperatures, humidity and air quality using smart phones. At the same time, the system detects possible flames, and analyzes and monitors electrical load. The monitoring also includes detecting the vibrations of operating machinery in the factory area. The research proposes using ZigBee and Wi-Fi protocol intelligent monitoring system integration within the entire plant framework. The sensors on the factory site deliver messages and real-time sensing data to an integrated embedded systems via the ZigBee protocol. The integrated embedded system is built by the open-source 32-bit ARM (Advanced RISC Machine) core Arduino Due module, where the network control codes are built in for the ARM chipset integrated controller. The intelligent integrated controller is able to instantly provide numerical analysis results according to the received data from the ZigBee sensors. The Android APP and web-based platform are used to show measurement results. The built-up system will transfer these results to a specified cloud device using the TCP/IP protocol. Finally, the Fast Fourier Transform (FFT) approach is used to analyze the power loads in the factory zones. Moreover, Near Field Communication (NFC) technology is used to carry out the actual electricity load experiments using smart phones. PMID:24351642

Mobile monitoring and embedded control system for factory environment.

PubMed

Lian, Kuang-Yow; Hsiao, Sung-Jung; Sung, Wen-Tsai

2013-12-17

This paper proposes a real-time method to carry out the monitoring of factory zone temperatures, humidity and air quality using smart phones. At the same time, the system detects possible flames, and analyzes and monitors electrical load. The monitoring also includes detecting the vibrations of operating machinery in the factory area. The research proposes using ZigBee and Wi-Fi protocol intelligent monitoring system integration within the entire plant framework. The sensors on the factory site deliver messages and real-time sensing data to an integrated embedded systems via the ZigBee protocol. The integrated embedded system is built by the open-source 32-bit ARM (Advanced RISC Machine) core Arduino Due module, where the network control codes are built in for the ARM chipset integrated controller. The intelligent integrated controller is able to instantly provide numerical analysis results according to the received data from the ZigBee sensors. The Android APP and web-based platform are used to show measurement results. The built-up system will transfer these results to a specified cloud device using the TCP/IP protocol. Finally, the Fast Fourier Transform (FFT) approach is used to analyze the power loads in the factory zones. Moreover, Near Field Communication (NFC) technology is used to carry out the actual electricity load experiments using smart phones.

Shuttle Payload Ground Command and Control: An Experiment Implementation Combustion Module-2 Software Development, STS-107

NASA Technical Reports Server (NTRS)

Carek, David Andrew

2003-01-01

This presentation covers the design of a command and control architecture developed by the author for the Combustion Module-2 microgravity experiment, which flew aboard the STS-107 Shuttle mission, The design was implemented to satisfy a hybrid network that utilized TCP/IP for both the onboard segment and ground segment, with an intermediary unreliable transport for the space to ground segment. With the infusion of Internet networking technologies into Space Shuttle, Space Station, and spacecraft avionics systems, comes the need for robust methodologies for ground command and control. Considerations of high bit error links, and unreliable transport over intermittent links must be considered in such systems. Internet protocols applied to these systems, coupled with the appropriate application layer protections, can provide adequate communication architectures for command and control. However, there are inherent limitations and additional complexities added by the use of Internet protocols that must be considered during the design. This presentation will discuss the rationale for the: framework and protocol algorithms developed by the author. A summary of design considerations, implantation issues, and learned lessons will be will be presented. A summary of mission results using this communications architecture will be presented. Additionally, areas of further needed investigation will be identified.

Transitioning to Low-GWP Alternatives in Unitary Air Conditioning

EPA Pesticide Factsheets

This fact sheet provides current information on low-Global Warming Potential (GWP) refrigerant alternatives used in unitary air-conditioning equipment, relevant to the Montreal Protocol on Substances that Deplete the Ozone Layer.

Hey! A Flea Bit Me!

MedlinePlus

... Staying Safe Videos for Educators Search English Español Hey! A Flea Bit Me! KidsHealth / For Kids / Hey! A Flea Bit Me! Print en español ¡Ay! ¡ ... 30% DEET. More on this topic for: Kids Hey! A Gnat Bit Me! Hey! A Bedbug Bit ...

Hey! A Louse Bit Me!

MedlinePlus

... Staying Safe Videos for Educators Search English Español Hey! A Louse Bit Me! KidsHealth / For Kids / Hey! A Louse Bit Me! Print en español ¡Ay! ¡ ... topic for: Kids Lice Aren't So Nice Hey! A Gnat Bit Me! Hey! A Flea Bit ...

PDC bits: What`s needed to meet tomorrow`s challenge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warren, T.M.; Sinor, L.A.

1994-12-31

When polycrystalline diamond compact (PDC) bits were introduced in the mid-1970s they showed tantalizingly high penetration rates in laboratory drilling tests. Single cutter tests indicated that they had the potential to drill very hard rocks. Unfortunately, 20 years later we`re still striving to reach the potential that these bits seem to have. Many problems have been overcome, and PDC bits have offered capabilities not possible with roller cone bits. PDC bits provide the most economical bit choice in many areas, but their limited durability has hampered their application in many other areas.

Experiences with http/WebDAV protocols for data access in high throughput computing

NASA Astrophysics Data System (ADS)

Bernabeu, Gerard; Martinez, Francisco; Acción, Esther; Bria, Arnau; Caubet, Marc; Delfino, Manuel; Espinal, Xavier

2011-12-01

In the past, access to remote storage was considered to be at least one order of magnitude slower than local disk access. Improvement on network technologies provide the alternative of using remote disk. For those accesses one can today reach levels of throughput similar or exceeding those of local disks. Common choices as access protocols in the WLCG collaboration are RFIO, [GSI]DCAP, GRIDFTP, XROOTD and NFS. HTTP protocol shows a promising alternative as it is a simple, lightweight protocol. It also enables the use of standard technologies such as http caching or load balancing which can be used to improve service resilience and scalability or to boost performance for some use cases seen in HEP such as the "hot files". WebDAV extensions allow writing data, giving it enough functionality to work as a remote access protocol. This paper will show our experiences with the WebDAV door for dCache, in terms of functionality and performance, applied to some of the HEP work flows in the LHC Tier1 at PIC.

Symmetric Blind Information Reconciliation for Quantum Key Distribution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kiktenko, Evgeniy O.; Trushechkin, Anton S.; Lim, Charles Ci Wen

Quantum key distribution (QKD) is a quantum-proof key-exchange scheme which is fast approaching the communication industry. An essential component in QKD is the information reconciliation step, which is used for correcting the quantum-channel noise errors. The recently suggested blind-reconciliation technique, based on low-density parity-check codes, offers remarkable prospectives for efficient information reconciliation without an a priori quantum bit error rate estimation. We suggest an improvement of the blind-information-reconciliation protocol promoting a significant increase in the efficiency of the procedure and reducing its interactivity. Finally, the proposed technique is based on introducing symmetry in operations of parties, and the consideration ofmore » results of unsuccessful belief-propagation decodings.« less

Symmetric Blind Information Reconciliation for Quantum Key Distribution

DOE PAGES

Kiktenko, Evgeniy O.; Trushechkin, Anton S.; Lim, Charles Ci Wen; ...

2017-10-27

Quantum key distribution (QKD) is a quantum-proof key-exchange scheme which is fast approaching the communication industry. An essential component in QKD is the information reconciliation step, which is used for correcting the quantum-channel noise errors. The recently suggested blind-reconciliation technique, based on low-density parity-check codes, offers remarkable prospectives for efficient information reconciliation without an a priori quantum bit error rate estimation. We suggest an improvement of the blind-information-reconciliation protocol promoting a significant increase in the efficiency of the procedure and reducing its interactivity. Finally, the proposed technique is based on introducing symmetry in operations of parties, and the consideration ofmore » results of unsuccessful belief-propagation decodings.« less

Experimentally Generated Random Numbers Certified by the Impossibility of Superluminal Signaling

NASA Astrophysics Data System (ADS)

Bierhorst, Peter; Shalm, Lynden K.; Mink, Alan; Jordan, Stephen; Liu, Yi-Kai; Rommal, Andrea; Glancy, Scott; Christensen, Bradley; Nam, Sae Woo; Knill, Emanuel

Random numbers are an important resource for applications such as numerical simulation and secure communication. However, it is difficult to certify whether a physical random number generator is truly unpredictable. Here, we exploit the phenomenon of quantum nonlocality in a loophole-free photonic Bell test experiment to obtain data containing randomness that cannot be predicted by any theory that does not also allow the sending of signals faster than the speed of light. To certify and quantify the randomness, we develop a new protocol that performs well in an experimental regime characterized by low violation of Bell inequalities. Applying an extractor function to our data, we obtain 256 new random bits, uniform to within 10- 3 .

Multipartite nonlocality distillation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsu, Li-Yi; Wu, Keng-Shuo

2010-11-15

The stronger nonlocality than that allowed in quantum theory can provide an advantage in information processing and computation. Since quantum entanglement is distillable, can nonlocality be distilled in the nonsignalling condition? The answer is positive in the bipartite case. In this article the distillability of the multipartite nonlocality is investigated. We propose a distillation protocol solely exploiting xor operations on output bits. The probability-distribution vectors and matrix are introduced to tackle the correlators. It is shown that only the correlators with extreme values can survive the distillation process. As the main result, the amplified nonlocality cannot maximally violate any Bell-typemore » inequality. Accordingly, a distillability criterion in the postquantum region is proposed.« less

Performance analysis of dual-hop optical wireless communication systems over k-distribution turbulence channel with pointing error

NASA Astrophysics Data System (ADS)

Mishra, Neha; Sriram Kumar, D.; Jha, Pranav Kumar

2017-06-01

In this paper, we investigate the performance of the dual-hop free space optical (FSO) communication systems under the effect of strong atmospheric turbulence together with misalignment effects (pointing error). We consider a relay assisted link using decode and forward (DF) relaying protocol between source and destination with the assumption that Channel State Information is available at both transmitting and receiving terminals. The atmospheric turbulence channels are modeled by k-distribution with pointing error impairment. The exact closed form expression is derived for outage probability and bit error rate and illustrated through numerical plots. Further BER results are compared for the different modulation schemes.

Symmetric Blind Information Reconciliation for Quantum Key Distribution

NASA Astrophysics Data System (ADS)

Kiktenko, E. O.; Trushechkin, A. S.; Lim, C. C. W.; Kurochkin, Y. V.; Fedorov, A. K.

2017-10-01

Quantum key distribution (QKD) is a quantum-proof key-exchange scheme which is fast approaching the communication industry. An essential component in QKD is the information reconciliation step, which is used for correcting the quantum-channel noise errors. The recently suggested blind-reconciliation technique, based on low-density parity-check codes, offers remarkable prospectives for efficient information reconciliation without an a priori quantum bit error rate estimation. We suggest an improvement of the blind-information-reconciliation protocol promoting a significant increase in the efficiency of the procedure and reducing its interactivity. The proposed technique is based on introducing symmetry in operations of parties, and the consideration of results of unsuccessful belief-propagation decodings.

Summary of Altitude Pulse Testing of a 100-lbf L02/LCH4 Reaction Control Engine

NASA Technical Reports Server (NTRS)

Marshall, William M.; Kleinhenz, Julie E.

2011-01-01

Recently, liquid oxygen-liquid methane (LO2/LCH4) has been considered as a potential "green" propellant alternative for future exploration missions. The Propulsion and Cryogenic Advanced Development (PCAD) project has been tasked by NASA to develop this propulsion combination to enable safe and cost effective exploration missions. To date, limited experience with such combinations exist, and as a result a comprehensive test program is critical to demonstrating the viability of implementing such a system. The NASA Glenn Research Center has conducted a test program of a 100-lbf (445-N) reaction control engine (RCE) at the center s Altitude Combustion Stand (ACS), focusing on altitude testing over a wide variety of operational conditions. The ACS facility includes a unique propellant conditioning feed system (PCFS) which allows precise control of propellant inlet conditions to the engine. Engine performance as a result of these inlet conditions was examined extensively during the test program. This paper is a companion to the previous specific impulse testing paper, and discusses the pulsed mode operation portion of testing, with a focus on minimum impulse bit (I-bit) and repeatable pulse performance. The engine successfully demonstrated target minimum impulse bit performance at all conditions, as well as successful demonstration of repeatable pulse widths. Some anomalous conditions experienced during testing are also discussed, including a double pulse phenomenon which was not noted in previous test programs for this engine.

FastBit Reference Manual

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Kesheng

2007-08-02

An index in a database system is a data structure that utilizes redundant information about the base data to speed up common searching and retrieval operations. Most commonly used indexes are variants of B-trees, such as B+-tree and B*-tree. FastBit implements a set of alternative indexes call compressed bitmap indexes. Compared with B-tree variants, these indexes provide very efficient searching and retrieval operations by sacrificing the efficiency of updating the indexes after the modification of an individual record. In addition to the well-known strengths of bitmap indexes, FastBit has a special strength stemming from the bitmap compression scheme used. Themore » compression method is called the Word-Aligned Hybrid (WAH) code. It reduces the bitmap indexes to reasonable sizes and at the same time allows very efficient bitwise logical operations directly on the compressed bitmaps. Compared with the well-known compression methods such as LZ77 and Byte-aligned Bitmap code (BBC), WAH sacrifices some space efficiency for a significant improvement in operational efficiency. Since the bitwise logical operations are the most important operations needed to answer queries, using WAH compression has been shown to answer queries significantly faster than using other compression schemes. Theoretical analyses showed that WAH compressed bitmap indexes are optimal for one-dimensional range queries. Only the most efficient indexing schemes such as B+-tree and B*-tree have this optimality property. However, bitmap indexes are superior because they can efficiently answer multi-dimensional range queries by combining the answers to one-dimensional queries.« less

Performance of an optical identification and interrogation system

NASA Astrophysics Data System (ADS)

Venugopalan, A.; Ghosh, A. K.; Verma, P.; Cheng, S.

2008-04-01

A free space optics based identification and interrogation system has been designed. The applications of the proposed system lie primarily in areas which require a secure means of mutual identification and information exchange between optical readers and tags. Conventional RFIDs raise issues regarding security threats, electromagnetic interference and health safety. The security of RF-ID chips is low due to the wide spatial spread of radio waves. Malicious nodes can read data being transmitted on the network, if they are in the receiving range. The proposed system provides an alternative which utilizes the narrow paraxial beams of lasers and an RSA-based authentication scheme. These provide enhanced security to communication between a tag and the base station or reader. The optical reader can also perform remote identification and the tag can be read from a far off distance, given line of sight. The free space optical identification and interrogation system can be used for inventory management, security systems at airports, port security, communication with high security systems, etc. to name a few. The proposed system was implemented with low-cost, off-the-shelf components and its performance in terms of throughput and bit error rate has been measured and analyzed. The range of operation with a bit-error-rate lower than 10-9 was measured to be about 4.5 m. The security of the system is based on the strengths of the RSA encryption scheme implemented using more than 1024 bits.

A novel hybrid auditory BCI paradigm combining ASSR and P300.

PubMed

Kaongoen, Netiwit; Jo, Sungho

2017-03-01

Brain-computer interface (BCI) is a technology that provides an alternative way of communication by translating brain activities into digital commands. Due to the incapability of using the vision-dependent BCI for patients who have visual impairment, auditory stimuli have been used to substitute the conventional visual stimuli. This paper introduces a hybrid auditory BCI that utilizes and combines auditory steady state response (ASSR) and spatial-auditory P300 BCI to improve the performance for the auditory BCI system. The system works by simultaneously presenting auditory stimuli with different pitches and amplitude modulation (AM) frequencies to the user with beep sounds occurring randomly between all sound sources. Attention to different auditory stimuli yields different ASSR and beep sounds trigger the P300 response when they occur in the target channel, thus the system can utilize both features for classification. The proposed ASSR/P300-hybrid auditory BCI system achieves 85.33% accuracy with 9.11 bits/min information transfer rate (ITR) in binary classification problem. The proposed system outperformed the P300 BCI system (74.58% accuracy with 4.18 bits/min ITR) and the ASSR BCI system (66.68% accuracy with 2.01 bits/min ITR) in binary-class problem. The system is completely vision-independent. This work demonstrates that combining ASSR and P300 BCI into a hybrid system could result in a better performance and could help in the development of the future auditory BCI. Copyright © 2017 Elsevier B.V. All rights reserved.

Xrootd in dCache - design and experiences

NASA Astrophysics Data System (ADS)

Behrmann, Gerd; Ozerov, Dmitry; Zangerl, Thomas

2011-12-01

dCache is a well established distributed storage solution used in both high energy physics computing and other disciplines. An overview of the implementation of the xrootd data access protocol within dCache is presented. The performance of various access mechanisms is studied and compared and it is concluded that our implementation is as perfomant as other protocols. This makes dCache a compelling alternative to the Scalla software suite implementation of xrootd, with added value from broad protocol support, including the IETF approved NFS 4.1 protocol.

Physiological response of rats to delivery of helium and xenon: implications for hyperpolarized noble gas imaging

NASA Technical Reports Server (NTRS)

Ramirez, M. P.; Sigaloff, K. C.; Kubatina, L. V.; Donahue, M. A.; Venkatesh, A. K.; Albert, M. S.; ALbert, M. S. (Principal Investigator)

2000-01-01

The physiological effects of various hyperpolarized helium and xenon MRI-compatible breathing protocols were investigated in 17 Sprague-Dawley rats, by continuous monitoring of blood oxygen saturation, heart rate, EKG, temperature and endotracheal pressure. The protocols included alternating breaths of pure noble gas and oxygen, continuous breaths of pure noble gas, breath-holds of pure noble gas for varying durations, and helium breath-holds preceded by two helium rinses. Alternate-breath protocols up to 128 breaths caused a decrease in oxygen saturation level of less than 5% for either helium or xenon, whereas 16 continuous-breaths caused a 31.5% +/- 2.3% decrease in oxygen saturation for helium and a 30.7% +/- 1. 3% decrease for xenon. Breath-hold protocols up to 25 s did not cause the oxygen saturation to fall below 90% for either of the noble gases. Oxygen saturation values below 90% are considered pathological. At 30 s of breath-hold, the blood oxygen saturation dropped precipitously to 82% +/- 0.6% for helium, and to 76.5% +/- 7. 4% for xenon. Breath-holds longer than 10 s preceded by pre-rinses caused oxygen saturation to drop below 90%. These findings demonstrate the need for standardized noble gas inhalation procedures that have been carefully tested, and for continuous physiological monitoring to ensure the safety of the subject. We find short breath-hold and alternate-breath protocols to be safe procedures for use in hyperpolarized noble gas MRI experiments. Copyright 2000 John Wiley & Sons, Ltd.

Development of an Innovative Algorithm for Aerodynamics-Structure Interaction Using Lattice Boltzmann Method

NASA Technical Reports Server (NTRS)

Mei, Ren-Wei; Shyy, Wei; Yu, Da-Zhi; Luo, Li-Shi; Rudy, David (Technical Monitor)

2001-01-01

The lattice Boltzmann equation (LBE) is a kinetic formulation which offers an alternative computational method capable of solving fluid dynamics for various systems. Major advantages of the method are owing to the fact that the solution for the particle distribution functions is explicit, easy to implement, and the algorithm is natural to parallelize. In this final report, we summarize the works accomplished in the past three years. Since most works have been published, the technical details can be found in the literature. Brief summary will be provided in this report. In this project, a second-order accurate treatment of boundary condition in the LBE method is developed for a curved boundary and tested successfully in various 2-D and 3-D configurations. To evaluate the aerodynamic force on a body in the context of LBE method, several force evaluation schemes have been investigated. A simple momentum exchange method is shown to give reliable and accurate values for the force on a body in both 2-D and 3-D cases. Various 3-D LBE models have been assessed in terms of efficiency, accuracy, and robustness. In general, accurate 3-D results can be obtained using LBE methods. The 3-D 19-bit model is found to be the best one among the 15-bit, 19-bit, and 27-bit LBE models. To achieve desired grid resolution and to accommodate the far field boundary conditions in aerodynamics computations, a multi-block LBE method is developed by dividing the flow field into various blocks each having constant lattice spacing. Substantial contribution to the LBE method is also made through the development of a new, generalized lattice Boltzmann equation constructed in the moment space in order to improve the computational stability, detailed theoretical analysis on the stability, dispersion, and dissipation characteristics of the LBE method, and computational studies of high Reynolds number flows with singular gradients. Finally, a finite difference-based lattice Boltzmann method is developed for inviscid compressible flows.

On-board processing satellite network architecture and control study

NASA Technical Reports Server (NTRS)

Campanella, S. Joseph; Pontano, B.; Chalmers, H.

1987-01-01

For satellites to remain a vital part of future national and international communications, system concepts that use their inherent advantages to the fullest must be created. Network architectures that take maximum advantage of satellites equipped with onboard processing are explored. Satellite generations must accommodate various services for which satellites constitute the preferred vehicle of delivery. Such services tend to be those that are widely dispersed and present thin to medium loads to the system. Typical systems considered are thin and medium route telephony, maritime, land and aeronautical radio, VSAT data, low bit rate video teleconferencing, and high bit rate broadcast of high definition video. Delivery of services by TDMA and FDMA multiplexing techniques and combinations of the two for individual and mixed service types are studied. The possibilities offered by onboard circuit switched and packet switched architectures are examined and the results strongly support a preference for the latter. A detailed design architecture encompassing the onboard packet switch and its control, the related demand assigned TDMA burst structures, and destination packet protocols for routing traffic are presented. Fundamental onboard hardware requirements comprising speed, memory size, chip count, and power are estimated. The study concludes with identification of key enabling technologies and identifies a plan to develop a POC model.

Southern blotting.

PubMed

Brown, T

2001-05-01

Southern blotting is the transfer of DNA fragments from an electrophoresis gel to a membrane support, resulting in immobilization of the DNA fragments, so the membrane carries a semipermanent reproduction of the banding pattern of the gel. After immobilization, the DNA can be subjected to hybridization analysis, enabling bands with sequence similarity to a labeled probe to be identified. This unit describes Southern blotting via upward capillary transfer of DNA from an agarose gel onto a nylon or nitrocellulose membrane, and subsequent immobilization by UV irradiation (for nylon) or baking (for nitrocellulose). A Support Protocol describes how to calibrate a UV transilluminator for optimal UV irradiation of a nylon membrane. An alternate protocol details transfer using nylon membranes and an alkaline buffer, and is primarily used with positively charged nylon membranes. A second alternate protocol describes a transfer method based on a different transfer-stack setup. The traditional method of upward capillary transfer of DNA from gel to membrane has certain disadvantages, notably the fact that the gel can become crushed by the weighted filter papers and paper towels that are laid on top of it. This slows down the blotting process and may reduce the amount of DNA that can be transferred. The downward capillary method described in the second alternate protocol is therefore more rapid and can result in more complete transfer.

High bit depth infrared image compression via low bit depth codecs

NASA Astrophysics Data System (ADS)

Belyaev, Evgeny; Mantel, Claire; Forchhammer, Søren

2017-08-01

Future infrared remote sensing systems, such as monitoring of the Earth's environment by satellites, infrastructure inspection by unmanned airborne vehicles etc., will require 16 bit depth infrared images to be compressed and stored or transmitted for further analysis. Such systems are equipped with low power embedded platforms where image or video data is compressed by a hardware block called the video processing unit (VPU). However, in many cases using two 8-bit VPUs can provide advantages compared with using higher bit depth image compression directly. We propose to compress 16 bit depth images via 8 bit depth codecs in the following way. First, an input 16 bit depth image is mapped into 8 bit depth images, e.g., the first image contains only the most significant bytes (MSB image) and the second one contains only the least significant bytes (LSB image). Then each image is compressed by an image or video codec with 8 bits per pixel input format. We analyze how the compression parameters for both MSB and LSB images should be chosen to provide the maximum objective quality for a given compression ratio. Finally, we apply the proposed infrared image compression method utilizing JPEG and H.264/AVC codecs, which are usually available in efficient implementations, and compare their rate-distortion performance with JPEG2000, JPEG-XT and H.265/HEVC codecs supporting direct compression of infrared images in 16 bit depth format. A preliminary result shows that two 8 bit H.264/AVC codecs can achieve similar result as 16 bit HEVC codec.

Bit-1 Mediates Integrin-dependent Cell Survival through Activation of the NFκB Pathway*

PubMed Central

Griffiths, Genevieve S.; Grundl, Melanie; Leychenko, Anna; Reiter, Silke; Young-Robbins, Shirley S.; Sulzmaier, Florian J.; Caliva, Maisel J.; Ramos, Joe W.; Matter, Michelle L.

2011-01-01

Loss of properly regulated cell death and cell survival pathways can contribute to the development of cancer and cancer metastasis. Cell survival signals are modulated by many different receptors, including integrins. Bit-1 is an effector of anoikis (cell death due to loss of attachment) in suspended cells. The anoikis function of Bit-1 can be counteracted by integrin-mediated cell attachment. Here, we explored integrin regulation of Bit-1 in adherent cells. We show that knockdown of endogenous Bit-1 in adherent cells decreased cell survival and re-expression of Bit-1 abrogated this effect. Furthermore, reduction of Bit-1 promoted both staurosporine and serum-deprivation induced apoptosis. Indeed knockdown of Bit-1 in these cells led to increased apoptosis as determined by caspase-3 activation and positive TUNEL staining. Bit-1 expression protected cells from apoptosis by increasing phospho-IκB levels and subsequently bcl-2 gene transcription. Protection from apoptosis under serum-free conditions correlated with bcl-2 transcription and Bcl-2 protein expression. Finally, Bit-1-mediated regulation of bcl-2 was dependent on focal adhesion kinase, PI3K, and AKT. Thus, we have elucidated an integrin-controlled pathway in which Bit-1 is, in part, responsible for the survival effects of cell-ECM interactions. PMID:21383007

Causes of wear of PDC bits and ways of improving their wear resistance

NASA Astrophysics Data System (ADS)

Timonin, VV; Smolentsev, AS; Shakhtorin, I. O.; Polushin, NI; Laptev, AI; Kushkhabiev, AS

2017-02-01

The scope of the paper encompasses basic factors that influence PDC bit efficiency. Feasible ways of eliminating the negatives are illustrated. The wash fluid flow in a standard bit is modeled, the resultant pattern of the bit washing is analyzed, and the recommendations are made on modification of the PDC bit design.

Changing Medicaid and Intermediate Care Facilities for the Mentally Retarded (ICF/MR): Evaluation of Alternatives.

ERIC Educational Resources Information Center

Fernald, Charles Denton

1986-01-01

Some alternatives for changing IFC are evaluated, and a model that can be used for considering other alternatives is presented. Proposals include a system of treatment protocols for diagnosis-related groups and a revision of S.873, The Community and Family Living Amendments of 1985. (Author/CL)

Image processing on the image with pixel noise bits removed

NASA Astrophysics Data System (ADS)

Chuang, Keh-Shih; Wu, Christine

1992-06-01

Our previous studies used statistical methods to assess the noise level in digital images of various radiological modalities. We separated the pixel data into signal bits and noise bits and demonstrated visually that the removal of the noise bits does not affect the image quality. In this paper we apply image enhancement techniques on noise-bits-removed images and demonstrate that the removal of noise bits has no effect on the image property. The image processing techniques used are gray-level look up table transformation, Sobel edge detector, and 3-D surface display. Preliminary results show no noticeable difference between original image and noise bits removed image using look up table operation and Sobel edge enhancement. There is a slight enhancement of the slicing artifact in the 3-D surface display of the noise bits removed image.

Drilling and Caching Architecture for the Mars2020 Mission

NASA Astrophysics Data System (ADS)

Zacny, K.

2013-12-01

We present a Sample Acquisition and Caching (SAC) architecture for the Mars2020 mission and detail how the architecture meets the sampling requirements described in the Mars2020 Science Definition Team (SDT) report. The architecture uses 'One Bit per Core' approach. Having dedicated bit for each rock core allows a reduction in the number of core transfer steps and actuators and this reduces overall mission risk. It also alleviates the bit life problem, eliminates cross contamination, and aids in hermetic sealing. An added advantage is faster drilling time, lower power, lower energy, and lower Weight on Bit (which reduces Arm preload requirements). To enable replacing of core samples, the drill bits are based on the BigTooth bit design. The BigTooth bit cuts a core diameter slightly smaller than the imaginary hole inscribed by the inner surfaces of the bits. Hence the rock core could be much easier ejected along the gravity vector. The architecture also has three additional types of bits that allow analysis of rocks. Rock Abrasion and Brushing Bit (RABBit) allows brushing and grinding of rocks in the same was as Rock Abrasion Tool does on MER. PreView bit allows viewing and analysis of rock core surfaces. Powder and Regolith Acquisition Bit (PRABit) captures regolith and rock powder either for in situ analysis or sample return. PRABit also allows sieving capabilities. The architecture can be viewed here: http://www.youtube.com/watch?v=_-hOO4-zDtE

Brownian motion properties of optoelectronic random bit generators based on laser chaos.

PubMed

Li, Pu; Yi, Xiaogang; Liu, Xianglian; Wang, Yuncai; Wang, Yongge

2016-07-11

The nondeterministic property of the optoelectronic random bit generator (RBG) based on laser chaos are experimentally analyzed from two aspects of the central limit theorem and law of iterated logarithm. The random bits are extracted from an optical feedback chaotic laser diode using a multi-bit extraction technique in the electrical domain. Our experimental results demonstrate that the generated random bits have no statistical distance from the Brownian motion, besides that they can pass the state-of-the-art industry-benchmark statistical test suite (NIST SP800-22). All of them give a mathematically provable evidence that the ultrafast random bit generator based on laser chaos can be used as a nondeterministic random bit source.

Drill bit assembly for releasably retaining a drill bit cutter

DOEpatents

Glowka, David A.; Raymond, David W.

2002-01-01

A drill bit assembly is provided for releasably retaining a polycrystalline diamond compact drill bit cutter. Two adjacent cavities formed in a drill bit body house, respectively, the disc-shaped drill bit cutter and a wedge-shaped cutter lock element with a removable fastener. The cutter lock element engages one flat surface of the cutter to retain the cutter in its cavity. The drill bit assembly thus enables the cutter to be locked against axial and/or rotational movement while still providing for easy removal of a worn or damaged cutter. The ability to adjust and replace cutters in the field reduces the effect of wear, helps maintains performance and improves drilling efficiency.

Flow cytometry for enrichment and titration in massively parallel DNA sequencing

PubMed Central

Sandberg, Julia; Ståhl, Patrik L.; Ahmadian, Afshin; Bjursell, Magnus K.; Lundeberg, Joakim

2009-01-01

Massively parallel DNA sequencing is revolutionizing genomics research throughout the life sciences. However, the reagent costs and labor requirements in current sequencing protocols are still substantial, although improvements are continuously being made. Here, we demonstrate an effective alternative to existing sample titration protocols for the Roche/454 system using Fluorescence Activated Cell Sorting (FACS) technology to determine the optimal DNA-to-bead ratio prior to large-scale sequencing. Our method, which eliminates the need for the costly pilot sequencing of samples during titration is capable of rapidly providing accurate DNA-to-bead ratios that are not biased by the quantification and sedimentation steps included in current protocols. Moreover, we demonstrate that FACS sorting can be readily used to highly enrich fractions of beads carrying template DNA, with near total elimination of empty beads and no downstream sacrifice of DNA sequencing quality. Automated enrichment by FACS is a simple approach to obtain pure samples for bead-based sequencing systems, and offers an efficient, low-cost alternative to current enrichment protocols. PMID:19304748

An Energy-Efficient and Robust Multipath Routing Protocol for Cognitive Radio Ad Hoc Networks.

PubMed

Singh, Kishor; Moh, Sangman

2017-09-04

Routing in cognitive radio ad hoc networks (CRAHNs) is a daunting task owing to dynamic topology, intermittent connectivity, spectrum heterogeneity, and energy constraints. Other prominent aspects such as channel stability, path reliability, and route discovery frequency should also be exploited. Several routing protocols have been proposed for CRAHNs in the literature. By stressing on one of the aspects more than any other, however, they do not satisfy all requirements of throughput, energy efficiency, and robustness. In this paper, we propose an energy-efficient and robust multipath routing (ERMR) protocol for CRAHNs by considering all prominent aspects including residual energy and channel stability in design. Even when the current routing path fails, the alternative routing path is immediately utilized. In establishing primary and alternative routing paths, both residual energy and channel stability are exploited simultaneously. Our simulation study shows that the proposed ERMR outperforms the conventional protocol in terms of network throughput, packet delivery ratio, energy consumption, and end-to-end delay.

An Energy-Efficient and Robust Multipath Routing Protocol for Cognitive Radio Ad Hoc Networks

PubMed Central

Singh, Kishor

2017-01-01

Routing in cognitive radio ad hoc networks (CRAHNs) is a daunting task owing to dynamic topology, intermittent connectivity, spectrum heterogeneity, and energy constraints. Other prominent aspects such as channel stability, path reliability, and route discovery frequency should also be exploited. Several routing protocols have been proposed for CRAHNs in the literature. By stressing on one of the aspects more than any other, however, they do not satisfy all requirements of throughput, energy efficiency, and robustness. In this paper, we propose an energy-efficient and robust multipath routing (ERMR) protocol for CRAHNs by considering all prominent aspects including residual energy and channel stability in design. Even when the current routing path fails, the alternative routing path is immediately utilized. In establishing primary and alternative routing paths, both residual energy and channel stability are exploited simultaneously. Our simulation study shows that the proposed ERMR outperforms the conventional protocol in terms of network throughput, packet delivery ratio, energy consumption, and end-to-end delay. PMID:28869551

Using Optimal Dependency-Trees for Combinatorial Optimization: Learning the Structure of the Search Space.

DTIC Science & Technology

1997-01-01

create a dependency tree containing an optimum set of n-1 first-order dependencies. To do this, first, we select an arbitrary bit Xroot to place at the...the root to an arbitrary bit Xroot -For all other bits Xi, set bestMatchingBitInTree[Xi] to Xroot . -While not all bits have been

Antiwhirl PDC bits increased penetration rates in Alberta drilling. [Polycrystalline Diamond Compact

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bobrosky, D.; Osmak, G.

1993-07-05

The antiwhirl PDC bits and an inhibitive mud system contributed to the quicker drilling of the time-sensitive shales. The hole washouts in the intermediate section were dramatically reduced, resulting in better intermediate casing cement jobs. Also, the use of antirotation PDC-drillable cementing plugs eliminated the need to drill out plugs and float equipment with a steel tooth bit and then trip for the PDC bit. By using an antiwhirl PDC bit, at least one trip was eliminated in the intermediate section. Offset data indicated that two to six conventional bits would have been required to drill the intermediate hole interval.more » The PDC bit was rebuildable and therefore rerunnable even after being used on five wells. In each instance, the cost of replacing chipped cutters was less than the cost of a new insert roller cone bit. The paper describes the antiwhirl bits; the development of the bits; and their application in a clastic sequence, a carbonate sequence, and the Shekilie oil field; the improvement in the rate of penetration; the selection of bottom hole assemblies; washout problems; and drill-out characteristics.« less

Evaluations of bit sleeve and twisted-body bit designs for controlling roof bolter dust

PubMed Central

Beck, T.W.

2015-01-01

Drilling into coal mine roof strata to install roof bolts has the potential to release substantial quantities of respirable dust. Due to the proximity of drill holes to the breathing zone of roof bolting personnel, dust escaping the holes and avoiding capture by the dust collection system pose a potential respiratory health risk. Controls are available to complement the typical dry vacuum collection system and minimize harmful exposures during the initial phase of drilling. This paper examines the use of a bit sleeve in combination with a dust-hog-type bit to improve dust extraction during the critical initial phase of drilling. A twisted-body drill bit is also evaluated to determine the quantity of dust liberated in comparison with the dust-hog-type bit. Based on the results of our laboratory tests, the bit sleeve may reduce dust emissions by one-half during the initial phase of drilling before the drill bit is fully enclosed by the drill hole. Because collaring is responsible for the largest dust liberations, overall dust emission can also be substantially reduced. The use of a twisted-body bit has minimal improvement on dust capture compared with the commonly used dust-hog-type bit. PMID:26257435

Sample Acquisition and Caching architecture for the Mars Sample Return mission

NASA Astrophysics Data System (ADS)

Zacny, K.; Chu, P.; Cohen, J.; Paulsen, G.; Craft, J.; Szwarc, T.

This paper presents a Mars Sample Return (MSR) Sample Acquisition and Caching (SAC) study developed for the three rover platforms: MER, MER+, and MSL. The study took into account 26 SAC requirements provided by the NASA Mars Exploration Program Office. For this SAC architecture, the reduction of mission risk was chosen by us as having greater priority than mass or volume. For this reason, we selected a “ One Bit per Core” approach. The enabling technology for this architecture is Honeybee Robotics' “ eccentric tubes” core breakoff approach. The breakoff approach allows the drill bits to be relatively small in diameter and in turn lightweight. Hence, the bits could be returned to Earth with the cores inside them with only a modest increase to the total returned mass, but a significant decrease in complexity. Having dedicated bits allows a reduction in the number of core transfer steps and actuators. It also alleviates the bit life problem, eliminates cross contamination, and aids in hermetic sealing. An added advantage is faster drilling time, lower power, lower energy, and lower Weight on Bit (which reduces Arm preload requirements). Drill bits are based on the BigTooth bit concept, which allows re-use of the same bit multiple times, if necessary. The proposed SAC consists of a 1) Rotary-Percussive Core Drill, 2) Bit Storage Carousel, 3) Cache, 4) Robotic Arm, and 5) Rock Abrasion and Brushing Bit (RABBit), which is deployed using the Drill. The system also includes PreView bits (for viewing of cores prior to caching) and Powder bits for acquisition of regolith or cuttings. The SAC total system mass is less than 22 kg for MER and MER+ size rovers and less than 32 kg for the MSL-size rover.

Heat Generation During Bone Drilling: A Comparison Between Industrial and Orthopaedic Drill Bits.

PubMed

Hein, Christopher; Inceoglu, Serkan; Juma, David; Zuckerman, Lee

2017-02-01

Cortical bone drilling for preparation of screw placement is common in multiple surgical fields. The heat generated while drilling may reach thresholds high enough to cause osteonecrosis. This can compromise implant stability. Orthopaedic drill bits are several orders more expensive than their similarly sized, publicly available industrial counterparts. We hypothesize that an industrial bit will generate less heat during drilling, and the bits will not generate more heat after multiple cortical passes. We compared 4 4.0 mm orthopaedic and 1 3.97 mm industrial drill bits. Three types of each bit were drilled into porcine femoral cortices 20 times. The temperature of the bone was measured with thermocouple transducers. The heat generated during the first 5 drill cycles for each bit was compared to the last 5 cycles. These data were analyzed with analysis of covariance. The industrial drill bit generated the smallest mean increase in temperature (2.8 ± 0.29°C) P < 0.0001. No significant difference was identified comparing the first 5 cortices drilled to the last 5 cortices drilled for each bit. The P-values are as follows: Bosch (P = 0.73), Emerge (P = 0.09), Smith & Nephew (P = 0.08), Stryker (P = 0.086), and Synthes (P = 0.16). The industrial bit generated less heat during drilling than its orthopaedic counterparts. The bits maintained their performance after 20 drill cycles. Consideration should be given by manufacturers to design differences that may contribute to a more efficient cutting bit. Further investigation into the reuse of these drill bits may be warranted, as our data suggest their efficiency is maintained after multiple uses.

A source-channel coding approach to digital image protection and self-recovery.

PubMed

Sarreshtedari, Saeed; Akhaee, Mohammad Ali

2015-07-01

Watermarking algorithms have been widely applied to the field of image forensics recently. One of these very forensic applications is the protection of images against tampering. For this purpose, we need to design a watermarking algorithm fulfilling two purposes in case of image tampering: 1) detecting the tampered area of the received image and 2) recovering the lost information in the tampered zones. State-of-the-art techniques accomplish these tasks using watermarks consisting of check bits and reference bits. Check bits are used for tampering detection, whereas reference bits carry information about the whole image. The problem of recovering the lost reference bits still stands. This paper is aimed at showing that having the tampering location known, image tampering can be modeled and dealt with as an erasure error. Therefore, an appropriate design of channel code can protect the reference bits against tampering. In the present proposed method, the total watermark bit-budget is dedicated to three groups: 1) source encoder output bits; 2) channel code parity bits; and 3) check bits. In watermark embedding phase, the original image is source coded and the output bit stream is protected using appropriate channel encoder. For image recovery, erasure locations detected by check bits help channel erasure decoder to retrieve the original source encoded image. Experimental results show that our proposed scheme significantly outperforms recent techniques in terms of image quality for both watermarked and recovered image. The watermarked image quality gain is achieved through spending less bit-budget on watermark, while image recovery quality is considerably improved as a consequence of consistent performance of designed source and channel codes.

Survey of Header Compression Techniques

NASA Technical Reports Server (NTRS)

Ishac, Joseph

2001-01-01

This report provides a summary of several different header compression techniques. The different techniques included are: (1) Van Jacobson's header compression (RFC 1144); (2) SCPS (Space Communications Protocol Standards) header compression (SCPS-TP, SCPS-NP); (3) Robust header compression (ROHC); and (4) The header compression techniques in RFC2507 and RFC2508. The methodology for compression and error correction for these schemes are described in the remainder of this document. All of the header compression schemes support compression over simplex links, provided that the end receiver has some means of sending data back to the sender. However, if that return path does not exist, then neither Van Jacobson's nor SCPS can be used, since both rely on TCP (Transmission Control Protocol). In addition, under link conditions of low delay and low error, all of the schemes perform as expected. However, based on the methodology of the schemes, each scheme is likely to behave differently as conditions degrade. Van Jacobson's header compression relies heavily on the TCP retransmission timer and would suffer an increase in loss propagation should the link possess a high delay and/or bit error rate (BER). The SCPS header compression scheme protects against high delay environments by avoiding delta encoding between packets. Thus, loss propagation is avoided. However, SCPS is still affected by an increased BER (bit-error-rate) since the lack of delta encoding results in larger header sizes. Next, the schemes found in RFC2507 and RFC2508 perform well for non-TCP connections in poor conditions. RFC2507 performance with TCP connections is improved by various techniques over Van Jacobson's, but still suffers a performance hit with poor link properties. Also, RFC2507 offers the ability to send TCP data without delta encoding, similar to what SCPS offers. ROHC is similar to the previous two schemes, but adds additional CRCs (cyclic redundancy check) into headers and improves compression schemes which provide better tolerances in conditions with a high BER.

Adjustable Nyquist-rate System for Single-Bit Sigma-Delta ADC with Alternative FIR Architecture

NASA Astrophysics Data System (ADS)

Frick, Vincent; Dadouche, Foudil; Berviller, Hervé

2016-09-01

This paper presents a new smart and compact system dedicated to control the output sampling frequency of an analogue-to-digital converters (ADC) based on single-bit sigma-delta (ΣΔ) modulator. This system dramatically improves the spectral analysis capabilities of power network analysers (power meters) by adjusting the ADC's sampling frequency to the input signal's fundamental frequency with a few parts per million accuracy. The trade-off between straightforwardness and performance that motivated the choice of the ADC's architecture are preliminary discussed. It particularly comes along with design considerations of an ultra-steep direct-form FIR that is optimised in terms of size and operating speed. Thanks to compact standard VHDL language description, the architecture of the proposed system is particularly suitable for application-specific integrated circuit (ASIC) implementation-oriented low-power and low-cost power meter applications. Field programmable gate array (FPGA) prototyping and experimental results validate the adjustable sampling frequency concept. They also show that the system can perform better in terms of implementation and power capabilities compared to dedicated IP resources.

An FPGA computing demo core for space charge simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Jinyuan; Huang, Yifei; /Fermilab

2009-01-01

In accelerator physics, space charge simulation requires large amount of computing power. In a particle system, each calculation requires time/resource consuming operations such as multiplications, divisions, and square roots. Because of the flexibility of field programmable gate arrays (FPGAs), we implemented this task with efficient use of the available computing resources and completely eliminated non-calculating operations that are indispensable in regular micro-processors (e.g. instruction fetch, instruction decoding, etc.). We designed and tested a 16-bit demo core for computing Coulomb's force in an Altera Cyclone II FPGA device. To save resources, the inverse square-root cube operation in our design is computedmore » using a memory look-up table addressed with nine to ten most significant non-zero bits. At 200 MHz internal clock, our demo core reaches a throughput of 200 M pairs/s/core, faster than a typical 2 GHz micro-processor by about a factor of 10. Temperature and power consumption of FPGAs were also lower than those of micro-processors. Fast and convenient, FPGAs can serve as alternatives to time-consuming micro-processors for space charge simulation.« less

On Information Metrics for Spatial Coding.

PubMed

Souza, Bryan C; Pavão, Rodrigo; Belchior, Hindiael; Tort, Adriano B L

2018-04-01

The hippocampal formation is involved in navigation, and its neuronal activity exhibits a variety of spatial correlates (e.g., place cells, grid cells). The quantification of the information encoded by spikes has been standard procedure to identify which cells have spatial correlates. For place cells, most of the established metrics derive from Shannon's mutual information (Shannon, 1948), and convey information rate in bits/s or bits/spike (Skaggs et al., 1993, 1996). Despite their widespread use, the performance of these metrics in relation to the original mutual information metric has never been investigated. In this work, using simulated and real data, we find that the current information metrics correlate less with the accuracy of spatial decoding than the original mutual information metric. We also find that the top informative cells may differ among metrics, and show a surrogate-based normalization that yields comparable spatial information estimates. Since different information metrics may identify different neuronal populations, we discuss current and alternative definitions of spatially informative cells, which affect the metric choice. Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.

Energy-Efficient Wide Datapath Integer Arithmetic Logic Units Using Superconductor Logic

NASA Astrophysics Data System (ADS)

Ayala, Christopher Lawrence

Complementary Metal-Oxide-Semiconductor (CMOS) technology is currently the most widely used integrated circuit technology today. As CMOS approaches the physical limitations of scaling, it is unclear whether or not it can provide long-term support for niche areas such as high-performance computing and telecommunication infrastructure, particularly with the emergence of cloud computing. Alternatively, superconductor technologies based on Josephson junction (JJ) switching elements such as Rapid Single Flux Quantum (RSFQ) logic and especially its new variant, Energy-Efficient Rapid Single Flux Quantum (ERSFQ) logic have the capability to provide an ultra-high-speed, low power platform for digital systems. The objective of this research is to design and evaluate energy-efficient, high-speed 32-bit integer Arithmetic Logic Units (ALUs) implemented using RSFQ and ERSFQ logic as the first steps towards achieving practical Very-Large-Scale-Integration (VLSI) complexity in digital superconductor electronics. First, a tunable VHDL superconductor cell library is created to provide a mechanism to conduct design exploration and evaluation of superconductor digital circuits from the perspectives of functionality, complexity, performance, and energy-efficiency. Second, hybrid wave-pipelining techniques developed earlier for wide datapath RSFQ designs have been used for efficient arithmetic and logic circuit implementations. To develop the core foundation of the ALU, the ripple-carry adder and the Kogge-Stone parallel prefix carry look-ahead adder are studied as representative candidates on opposite ends of the design spectrum. By combining the high-performance features of the Kogge-Stone structure and the low complexity of the ripple-carry adder, a 32-bit asynchronous wave-pipelined hybrid sparse-tree ALU has been designed and evaluated using the VHDL cell library tuned to HYPRES' gate-level characteristics. The designs and techniques from this research have been implemented using RSFQ logic and prototype chips have been fabricated. As a joint work with HYPRES, a 20 GHz 8-bit Kogge-Stone ALU consisting of 7,950 JJs total has been fabricated using a 1.5 μm 4.5 kA/cm2 process and fully demonstrated. An 8-bit sparse-tree ALU (8,832 JJs total) and a 16-bit sparse-tree adder (12,785 JJs total) have also been fabricated using a 1.0 μm 10 kA/cm 2 process and demonstrated under collaboration with Yokohama National University and Nagoya University (Japan).

Rendezvous Protocols and Dynamic Frequency Hopping Interference Design for Anti-Jamming Satellite Communication

DTIC Science & Technology

2013-11-25

previously considered this proactive approach to combat unintentional, persistent (non- reactive) interference . In this project, we plan on extending our...channel” (or code ) by chance, through public knowledge of the underlying protocol semantics , or by compromising one of the network devices. An alternative...AFRL-RV-PS- AFRL-RV-PS- TR-2013-0142 TR-2013-0142 RENDEZVOUS PROTOCOLS AND DYNAMIC FREQUENCY HOPPING INTERFERENCE DESIGN FOR ANTI-JAMMING

Theoretical and subjective bit assignments in transform picture

NASA Technical Reports Server (NTRS)

Jones, H. W., Jr.

1977-01-01

It is shown that all combinations of symmetrical input distributions with difference distortion measures give a bit assignment rule identical to the well-known rule for a Gaussian input distribution with mean-square error. Published work is examined to show that the bit assignment rule is useful for transforms of full pictures, but subjective bit assignments for transform picture coding using small block sizes are significantly different from the theoretical bit assignment rule. An intuitive explanation is based on subjective design experience, and a subjectively obtained bit assignment rule is given.

A brain-machine interface to navigate a mobile robot in a planar workspace: enabling humans to fly simulated aircraft with EEG.

PubMed

Akce, Abdullah; Johnson, Miles; Dantsker, Or; Bretl, Timothy

2013-03-01

This paper presents an interface for navigating a mobile robot that moves at a fixed speed in a planar workspace, with noisy binary inputs that are obtained asynchronously at low bit-rates from a human user through an electroencephalograph (EEG). The approach is to construct an ordered symbolic language for smooth planar curves and to use these curves as desired paths for a mobile robot. The underlying problem is then to design a communication protocol by which the user can, with vanishing error probability, specify a string in this language using a sequence of inputs. Such a protocol, provided by tools from information theory, relies on a human user's ability to compare smooth curves, just like they can compare strings of text. We demonstrate our interface by performing experiments in which twenty subjects fly a simulated aircraft at a fixed speed and altitude with input only from EEG. Experimental results show that the majority of subjects are able to specify desired paths despite a wide range of errors made in decoding EEG signals.

Calculation of key reduction for B92 QKD protocol

NASA Astrophysics Data System (ADS)

Mehic, Miralem; Partila, Pavol; Tovarek, Jaromir; Voznak, Miroslav

2015-05-01

It is well known that Quantum Key Distribution (QKD) can be used with the highest level of security for distribution of the secret key, which is further used for symmetrical encryption. B92 is one of the oldest QKD protocols. It uses only two non-orthogonal states, each one coding for one bit-value. It is much faster and simpler when compared to its predecessors, but with the idealized maximum efficiencies of 25% over the quantum channel. B92 consists of several phases in which initial key is significantly reduced: secret key exchange, extraction of the raw key (sifting), error rate estimation, key reconciliation and privacy amplification. QKD communication is performed over two channels: the quantum channel and the classical public channel. In order to prevent a man-in-the-middle attack and modification of messages on the public channel, authentication of exchanged values must be performed. We used Wegman-Carter authentication because it describes an upper bound for needed symmetric authentication key. We explained the reduction of the initial key in each of QKD phases.

Architectural and engineering issues for building an optical Internet

NASA Astrophysics Data System (ADS)

St. Arnaud, Bill

1998-10-01

Recent developments in high density Wave Division Multiplexing fiber systems allows for the deployment of a dedicated optical Internet network for large volume backbone pipes that does not require an underlying multi-service SONET/SDH and ATM transport protocol. Some intrinsic characteristics of Internet traffic such as its self similar nature, server bound congestion, routing and data asymmetry allow for highly optimized traffic engineered networks using individual wavelengths. By transmitting GigaBit Ethernet or SONET/SDH frames natively over WDM wavelengths that directly interconnect high performance routers the original concept of the Internet as an intrinsically survivable datagram network is possible. Traffic engineering, restoral, protection and bandwidth management of the network must now be carried out at the IP layer and so new routing or switching protocols such as MPLS that allow for uni- directional paths with fast restoral and protection at the IP layer become essential for a reliable production network. The deployment of high density WDM municipal and campus networks also gives carriers and ISPs the flexibility to offer customers as integrated and seamless set of optical Internet services.

Adaptive selective relaying in cooperative free-space optical systems over atmospheric turbulence and misalignment fading channels.

PubMed

Boluda-Ruiz, Rubén; García-Zambrana, Antonio; Castillo-Vázquez, Carmen; Castillo-Vázquez, Beatriz

2014-06-30

In this paper, a novel adaptive cooperative protocol with multiple relays using detect-and-forward (DF) over atmospheric turbulence channels with pointing errors is proposed. The adaptive DF cooperative protocol here analyzed is based on the selection of the optical path, source-destination or different source-relay links, with a greater value of fading gain or irradiance, maintaining a high diversity order. Closed-form asymptotic bit error-rate (BER) expressions are obtained for a cooperative free-space optical (FSO) communication system with Nr relays, when the irradiance of the transmitted optical beam is susceptible to either a wide range of turbulence conditions, following a gamma-gamma distribution of parameters α and β, or pointing errors, following a misalignment fading model where the effect of beam width, detector size and jitter variance is considered. A greater robustness for different link distances and pointing errors is corroborated by the obtained results if compared with similar cooperative schemes or equivalent multiple-input multiple-output (MIMO) systems. Simulation results are further demonstrated to confirm the accuracy and usefulness of the derived results.

Experimental purification of two-atom entanglement.

PubMed

Reichle, R; Leibfried, D; Knill, E; Britton, J; Blakestad, R B; Jost, J D; Langer, C; Ozeri, R; Seidelin, S; Wineland, D J

2006-10-19

Entanglement is a necessary resource for quantum applications--entanglement established between quantum systems at different locations enables private communication and quantum teleportation, and facilitates quantum information processing. Distributed entanglement is established by preparing an entangled pair of quantum particles in one location, and transporting one member of the pair to another location. However, decoherence during transport reduces the quality (fidelity) of the entanglement. A protocol to achieve entanglement 'purification' has been proposed to improve the fidelity after transport. This protocol uses separate quantum operations at each location and classical communication to distil high-fidelity entangled pairs from lower-fidelity pairs. Proof-of-principle experiments distilling entangled photon pairs have been carried out. However, these experiments obtained distilled pairs with a low probability of success and required destruction of the entangled pairs, rendering them unavailable for further processing. Here we report efficient and non-destructive entanglement purification with atomic quantum bits. Two noisy entangled pairs were created and distilled into one higher-fidelity pair available for further use. Success probabilities were above 35 per cent. The many applications of entanglement purification make it one of the most important techniques in quantum information processing.

Completely device-independent quantum key distribution

NASA Astrophysics Data System (ADS)

Aguilar, Edgar A.; Ramanathan, Ravishankar; Kofler, Johannes; Pawłowski, Marcin

2016-08-01

Quantum key distribution (QKD) is a provably secure way for two distant parties to establish a common secret key, which then can be used in a classical cryptographic scheme. Using quantum entanglement, one can reduce the necessary assumptions that the parties have to make about their devices, giving rise to device-independent QKD (DIQKD). However, in all existing protocols to date the parties need to have an initial (at least partially) random seed as a resource. In this work, we show that this requirement can be dropped. Using recent advances in the fields of randomness amplification and randomness expansion, we demonstrate that it is sufficient for the message the parties want to communicate to be (partially) unknown to the adversaries—an assumption without which any type of cryptography would be pointless to begin with. One party can use her secret message to locally generate a secret sequence of bits, which can then be openly used by herself and the other party in a DIQKD protocol. Hence our work reduces the requirements needed to perform secure DIQKD and establish safe communication.

Information trade-offs for optical quantum communication.

PubMed

Wilde, Mark M; Hayden, Patrick; Guha, Saikat

2012-04-06

Recent work has precisely characterized the achievable trade-offs between three key information processing tasks-classical communication (generation or consumption), quantum communication (generation or consumption), and shared entanglement (distribution or consumption), measured in bits, qubits, and ebits per channel use, respectively. Slices and corner points of this three-dimensional region reduce to well-known protocols for quantum channels. A trade-off coding technique can attain any point in the region and can outperform time sharing between the best-known protocols for accomplishing each information processing task by itself. Previously, the benefits of trade-off coding that had been found were too small to be of practical value (viz., for the dephasing and the universal cloning machine channels). In this Letter, we demonstrate that the associated performance gains are in fact remarkably high for several physically relevant bosonic channels that model free-space or fiber-optic links, thermal-noise channels, and amplifiers. We show that significant performance gains from trade-off coding also apply when trading photon-number resources between transmitting public and private classical information simultaneously over secret-key-assisted bosonic channels. © 2012 American Physical Society

Effect of bit wear on hammer drill handle vibration and productivity.

PubMed

Antonucci, Andrea; Barr, Alan; Martin, Bernard; Rempel, David

2017-08-01

The use of large electric hammer drills exposes construction workers to high levels of hand vibration that may lead to hand-arm vibration syndrome and other musculoskeletal disorders. The aim of this laboratory study was to investigate the effect of bit wear on drill handle vibration and drilling productivity (e.g., drilling time per hole). A laboratory test bench system was used with an 8.3 kg electric hammer drill and 1.9 cm concrete bit (a typical drill and bit used in commercial construction). The system automatically advanced the active drill into aged concrete block under feed force control to a depth of 7.6 cm while handle vibration was measured according to ISO standards (ISO 5349 and 28927). Bits were worn to 4 levels by consecutive hole drilling to 4 cumulative drilling depths: 0, 1,900, 5,700, and 7,600 cm. Z-axis handle vibration increased significantly (p<0.05) from 4.8 to 5.1 m/s 2 (ISO weighted) and from 42.7-47.6 m/s 2 (unweighted) when comparing a new bit to a bit worn to 1,900 cm of cumulative drilling depth. Handle vibration did not increase further with bits worn more than 1900 cm of cumulative drilling depth. Neither x- nor y-axis handle vibration was effected by bit wear. The time to drill a hole increased by 58% for the bit with 5,700 cm of cumulative drilling depth compared to a new bit. Bit wear led to a small but significant increase in both ISO weighted and unweighted z-axis handle vibration. Perhaps more important, bit wear had a large effect on productivity. The effect on productivity will influence a worker's allowable daily drilling time if exposure to drill handle vibration is near the ACGIH Threshold Limit Value. [1] Construction contractors should implement a bit replacement program based on these findings.

PDC bit hydraulics design, profile are key to reducing balling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hariharan, P.R.; Azar, J.J.

1996-12-09

Polycrystalline diamond compact (PDC) bits with a parabolic profile and bladed hydraulic design have a lesser tendency to ball during drilling of reactive shales. PDC bits with ribbed or open-face hydraulic designs and those with flat or rounded profiles tended to ball more often in the bit balling experiments conducted. Experimental work also indicates that PDC hydraulic design seems to have a greater influence on bit balling tendency compared to bit profile design. There are five main factors that affect bit balling: formation type, drilling fluid, drilling hydraulics, bit design, and confining pressures. An equation for specific energy showed thatmore » it could be used to describe the efficiency of the drilling process by examining the amount of energy spent in drilling a unit volume of rock. This concept of specific energy has been used herein to correlate with the parameter Rd, a parameter to quantify the degree of balling.« less

ALT-114 and ALT-118 Alternative Approaches to NIST ...

EPA Pesticide Factsheets

In 2016, US EPA approved two separate alternatives (ALT 114 and ALT 118) for the preparation and certification of Hydrogen Chloride (HCl) and Mercury (Hg) cylinder reference gas standards that can serve as EPA Protocol gases where EPA Protocol are required, but unavailable. The alternatives were necessary due to the unavailability of NIST reference materials (SRM, NTRM, CRM or RGM) or VSL reference materials (VSL PRM or VSL CRM), reference materials identified in EPA’s Green Book as necessary to establish the traceability of EPA protocol gases. ALT 114 and ALT 118 provides a pathway for gas vendors to prepare and certify traceable gas cylinder standards for use in certifying Hg and HCl CEMS. In this presentation, EPA will describe the mechanics and requirements of the performance-based approach, provide an update on the availability of these gas standards and also discuss the potential for producing and certifying gas standards for other compounds using this approach. This presentation discusses the importance of NIST-traceable reference gases relative to regulatory source compliance emissions monitoring. Specifically this presentation discusses 2 new approaches for making necessary reference gases available in the absence of NIST reference materials. Moreover, these approaches provide an alternative approach to rapidly make available new reference gases for additional HAPS regulatory compliance emissions measurement and monitoring.

Alternative energy input: Mechanochemical, microwave and ultrasound-assisted organic synthesis

EPA Science Inventory

Microwave, ultrasound, sunlight and mechanochemical mixing can be used to augment conventional laboratory techniques. By applying these alternative means of activation, a number of chemical transformations have been achieved thereby improving many existing protocols with superi...

Alternative technological development for RF hybridization

NASA Astrophysics Data System (ADS)

Antônio Finardi, Célio; da Fontoura Ponchet, André; Battesini Adamo, Cristina; Flacker, Alexander; Cotrin Teixeira, Ricardo; Panepucci, Roberto Ricardo

2017-03-01

The paper presents a technological solution for high frequency packaging platform evaluated up to 40 GHz. The main purpose of this development was to define an alternative hybrid technology that is more flexible and faster to prototype compared with thin film or multi chip module (MCM-D). The alternative technology also shows adequate performance for high bit rate solutions integrating optical and electronics blocks. This approach consists of a soft substrate (laminate material), plating processes (electroless Ni-P/Au, electrolytic Au) and lithography patterning. Ground coplanar waveguide was used for microwave structures with excellent ground planes connections due to easy via holes implementation. We present results of high frequency packaging of important RF blocks, such as integrated broadband bias-T, transimpedance amplifier ICs and silicon photonics optical modulators. The paper demonstrates a solution for high frequency hybridization that can be implemented with standard substrates, designed with any shape and with large numbers of metalized via holes and compatible with usual assembling techniques.

Remote drill bit loader

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dokos, J.A.

1996-12-31

A drill bit loader is described for loading a tapered shank of a drill bit into a similarly tapered recess in the end of a drill spindle. The spindle has a transverse slot at the inner end of the recess. The end of the tapered shank of the drill bit has a transverse tang adapted to engage in the slot so that the drill bit will be rotated by the spindle. The loader is in the form of a cylinder adapted to receive the drill bit with the shank projecting out of the outer end of the cylinder. Retainer pinsmore » prevent rotation of the drill bit in the cylinder. The spindle is lowered to extend the shank of the drill bit into the recess in the spindle and the spindle is rotated to align the slot in the spindle with the tang on the shank. A spring unit in the cylinder is compressed by the drill bit during its entry into the recess of the spindle and resiliently drives the tang into the slot in the spindle when the tang and slot are aligned. In typical remote drilling operations, whether in hot cells or water pits, drill bits have been held using a collet or end mill type holder with set screws. In either case, to load or change a drill bit required the use master-slave manipulators to position the bits and tighten the collet or set screws. This requirement eliminated many otherwise useful work areas because they were not equipped with slaves, particularly in water pits.« less

Remote drill bit loader

DOEpatents

Dokos, J.A.

1997-12-30

A drill bit loader is described for loading a tapered shank of a drill bit into a similarly tapered recess in the end of a drill spindle. The spindle has a transverse slot at the inner end of the recess. The end of the tapered shank of the drill bit has a transverse tang adapted to engage in the slot so that the drill bit will be rotated by the spindle. The loader is in the form of a cylinder adapted to receive the drill bit with the shank projecting out of the outer end of the cylinder. Retainer pins prevent rotation of the drill bit in the cylinder. The spindle is lowered to extend the shank of the drill bit into the recess in the spindle and the spindle is rotated to align the slot in the spindle with the tang on the shank. A spring unit in the cylinder is compressed by the drill bit during its entry into the recess of the spindle and resiliently drives the tang into the slot in the spindle when the tang and slot are aligned. 5 figs.

Region-of-interest determination and bit-rate conversion for H.264 video transcoding

NASA Astrophysics Data System (ADS)

Huang, Shu-Fen; Chen, Mei-Juan; Tai, Kuang-Han; Li, Mian-Shiuan

2013-12-01

This paper presents a video bit-rate transcoder for baseline profile in H.264/AVC standard to fit the available channel bandwidth for the client when transmitting video bit-streams via communication channels. To maintain visual quality for low bit-rate video efficiently, this study analyzes the decoded information in the transcoder and proposes a Bayesian theorem-based region-of-interest (ROI) determination algorithm. In addition, a curve fitting scheme is employed to find the models of video bit-rate conversion. The transcoded video will conform to the target bit-rate by re-quantization according to our proposed models. After integrating the ROI detection method and the bit-rate transcoding models, the ROI-based transcoder allocates more coding bits to ROI regions and reduces the complexity of the re-encoding procedure for non-ROI regions. Hence, it not only keeps the coding quality but improves the efficiency of the video transcoding for low target bit-rates and makes the real-time transcoding more practical. Experimental results show that the proposed framework gets significantly better visual quality.

Remote drill bit loader

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dokos, James A.

A drill bit loader for loading a tapered shank of a drill bit into a similarly tapered recess in the end of a drill spindle. The spindle has a transverse slot at the inner end of the recess. The end of the tapered shank of the drill bit has a transverse tang adapted to engage in the slot so that the drill bit will be rotated by the spindle. The loader is in the form of a cylinder adapted to receive the drill bit with the shank projecting out of the outer end of the cylinder. Retainer pins prevent rotationmore » of the drill bit in the cylinder. The spindle is lowered to extend the shank of the drill bit into the recess in the spindle and the spindle is rotated to align the slot in the spindle with the tang on the shank. A spring unit in the cylinder is compressed by the drill bit during its entry into the recess of the spindle and resiliently drives the tang into the slot in the spindle when the tang and slot are aligned.« less

Remote drill bit loader

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dokos, J.A.

A drill bit loader is described for loading a tapered shank of a drill bit into a similarly tapered recess in the end of a drill spindle. The spindle has a transverse slot at the inner end of the recess. The end of the tapered shank of the drill bit has a transverse tang adapted to engage in the slot so that the drill bit will be rotated by the spindle. The loader is in the form of a cylinder adapted to receive the drill bit with the shank projecting out of the outer end of the cylinder. Retainer pinsmore » prevent rotation of the drill bit in the cylinder. The spindle is lowered to extend the shank of the drill bit into the recess in the spindle and the spindle is rotated to align the slot in the spindle with the tang on the shank. A spring unit in the cylinder is compressed by the drill bit during its entry into the recess of the spindle and resiliently drives the tang into the slot in the spindle when the tang and slot are aligned. 5 figs.« less

Hybrid protocols plus natural treatments for inflammatory conditions.

PubMed

1998-01-01

Hybrid protocols combine one, two, or three pharmaceutical drugs with several nutritional or immune-based therapies. These protocols are not limited solely to FDA-approved drugs or strictly to alternative therapies. The rationale for using a hybrid protocol is to find an effective antiviral regimen that also restores immune function. The goal is to obtain the benefits of protease inhibitors without viral resistance and side effects which include problems with fat metabolism and cholesterol levels. Natural treatments for inflammatory conditions are also described. Options include licorice root, ginger root, and slippery elm.

Micromagnetic Study of Perpendicular Magnetic Recording Media

NASA Astrophysics Data System (ADS)

Dong, Yan

With increasing areal density in magnetic recording systems, perpendicular recording has successfully replaced longitudinal recording to mitigate the superparamagnetic limit. The extensive theoretical and experimental research associated with perpendicular magnetic recording media has contributed significantly to improving magnetic recording performance. Micromagnetic studies on perpendicular recording media, including aspects of the design of hybrid soft underlayers, media noise properties, inter-grain exchange characterization and ultra-high density bit patterned media recording, are presented in this dissertation. To improve the writability of recording media, one needs to reduce the head-to-keeper spacing while maintaining a good texture growth for the recording layer. A hybrid soft underlayer, consisting of a thin crystalline soft underlayer stacked above a non-magnetic seed layer and a conventional amorphous soft underlayer, provides an alternative approach for reducing the effective head-to-keeper spacing in perpendicular recording. Micromagnetic simulations indicate that the media using a hybrid soft underlayer helps enhance the effective field and the field gradient in comparison with conventional media that uses only an amorphous soft underlayer. The hybrid soft underlayer can support a thicker non-magnetic seed layer yet achieve an equivalent or better effective field and field gradient. A noise plateau for intermediate recording densities is observed for a recording layer of typical magnetization. Medium noise characteristics and transition jitter in perpendicular magnetic recording are explored using micromagnetic simulation. The plateau is replaced by a normal linear dependence of noise on recording density for a low magnetization recording layer. We show analytically that a source of the plateau is similar to that producing the Non-Linear-Transition-Shift of signal. In particular, magnetostatic effects are predicted to produce positive correlation of jitter and thus negative correlation of noise at the densities associated with the plateau. One focus for developing perpendicular recording media is on how to extract intergranular exchange coupling and intrinsic anisotropy field dispersion. A micromagnetic numerical technique is developed to effectively separate the effects of intergranular exchange coupling and anisotropy dispersion by finding their correlation to differentiated M-H curves with different initial magnetization states, even in the presence of thermal fluctuation. The validity of this method is investigated with a series of intergranular exchange couplings and anisotropy dispersions for different media thickness. This characterization method allows for an experimental measurement employing a vibrating sample magnetometer (VSM). Bit patterned media have been suggested to extend areal density beyond 1 Tbit/in2. The feasibility of 4 Tbit/in2 bit patterned recording is determined by aspects of write head design and media fabrication, and is estimated by the bit error rate. Micromagnetic specifications including 2.3:1 BAR bit patterned exchange coupled composite media, trailing shield, and side shields are proposed to meet the requirement of 3x10 -4 bit error rate, 4 nm fly height, 5% switching field distribution, 5% timing and 5% jitter errors for 4 Tbit/in2 bit-patterned recording. Demagnetizing field distribution is examined by studying the shielding effect of the side shields on the stray field from the neighboring dots. For recording self-assembled bit-patterned media, the head design writes two staggered tracks in a single pass and has maximum perpendicular field gradients of 580 Oe/nm along the down-track direction and 476 Oe/nm along the cross-track direction. The geometry demanded by self-assembly reduces recording density to 2.9 Tbit/in 2.

Graded bit patterned magnetic arrays fabricated via angled low-energy He ion irradiation.

PubMed

Chang, L V; Nasruallah, A; Ruchhoeft, P; Khizroev, S; Litvinov, D

2012-07-11

A bit patterned magnetic array based on Co/Pd magnetic multilayers with a binary perpendicular magnetic anisotropy distribution was fabricated. The binary anisotropy distribution was attained through angled helium ion irradiation of a bit edge using hydrogen silsesquioxane (HSQ) resist as an ion stopping layer to protect the rest of the bit. The viability of this technique was explored numerically and evaluated through magnetic measurements of the prepared bit patterned magnetic array. The resulting graded bit patterned magnetic array showed a 35% reduction in coercivity and a 9% narrowing of the standard deviation of the switching field.

Decision Making and the IACUC: Part 1—Protocol Information Discussed at Full-Committee Reviews

PubMed Central

Silverman, Jerald; Lidz, Charles W; Clayfield, Jonathan C; Murray, Alexandra; Simon, Lorna J; Rondeau, Richard G

2015-01-01

IACUC protocols can be reviewed by either the full committee or designated members. Both review methods use the principles of the 3 Rs (reduce, refine, replace) as the overarching paradigm, with federal regulations and policies providing more detailed guidance. The primary goal of this study was to determine the frequency of topics discussed by IACUC during full-committee reviews and whether the topics included those required for consideration by IACUC (for example, pain and distress, number of animals used, availability of alternatives, skill and experience of researchers). We recorded and transcribed 87 protocol discussions undergoing full-committee review at 10 academic institutions. Each transcript was coded to capture the key concepts of the discussion and analyzed for the frequency of the codes mentioned. Pain and distress was the code mentioned most often, followed by the specific procedures performed, the study design, and the completeness of the protocol form. Infrequently mentioned topics were alternatives to animal use or painful or distressful procedures, the importance of the research, and preliminary data. Not all of the topics required to be considered by the IACUC were openly discussed for all protocols, and many of the discussions were limited in their depth. PMID:26224439

Joint Test Protocol for Validation of Alternative Low-Emission Surface Preparation/Depainting Technologies for Structural Steel

NASA Technical Reports Server (NTRS)

Lewis, Pattie

2005-01-01

Headquarters National Aeronautics and Space Administration (NASA) chartered the Acquisition Pollution Prevention (AP2) Office to coordinate agency activities affecting pollution prevention issues identified during system and component acquisition and sustainment processes. The primary objectives of the AP2 Office are to: (1) Reduce or eliminate the use of hazardous materials (HazMats) or hazardous processes at manufacturing, remanufacturing, and sustainment locations. (2) A void duplication of effort in actions required to reduce or eliminate HazMats through joint center cooperation and technology sharing. This project will identify, evaluate and approve alternative surface preparation technologies for use at NASA and Air Force Space Command (AFSPC) installations. Materials and processes will be evaluated with the goal of selecting those processes that will improve corrosion protection at critical systems, facilitate easier maintenance activity, extend maintenance cycles, eliminate flight hardware contamination and reduce the amount of hazardous waste generated. This Joint Test Protocol (JTP) contains the critical requirements and tests necessary to qualify alternative Low-Emission Surface Preparation/Depainting Technologies for Structural Steel Applications. These tests were derived from engineering, performance, and operational impact (supportability) requirements defined by a consensus of NASA and Air Force Space Command (AFSPC) participants. The Field Test Plan (FTP), entitled Joint Test Protocol for Validation of Alternative Low Emission Surface Preparation/Depainting Technologies for Structural Steel, prepared by ITB, defines the field evaluation and testing requirements for validating alternative surface preparation/depainting technologies and supplements the JTP.

Triage and protocol recommendations for the parasitology laboratory based on an epidemiological investigation of parasite diagnostics in Ontario laboratories

PubMed Central

Maier, Allison; Krolik, Julia; Majury, Anna

2014-01-01

OBJECTIVES: A study was performed using a subset of Ontario laboratory parasitology data, with three objectives: to describe parasitic infections in Ontario; to identify risk factors for acquiring a parasitic infection using routinely collected information; and to use this information to assess current protocols for parasite testing in laboratories and, in turn, to propose alternatives to optimize the allocation of laboratory resources. METHODS: All parasitology records from January 4, 2010 to September 14, 2010 were reviewed descriptively and risk factor analyses were performed using information collected from requisitions. These results were used to develop preliminary alternative protocols, which considered high-throughput screening tests and inclusion/exclusion criteria for ova and parasite testing; these were then retrospectively analyzed with the dataset to determine appropriateness. RESULTS: Of the 29,260 records analyzed, 10% were multiple samples from single patients submitted on the same day, of which 98% had the same result. Three percent of all parasite tests were positive, with the most prevalent parasites being (in ascending order) Dientamoeba fragilis, Giardia lamblia, Cryptosporidium species and Entamoeba histolytica/dispar. Age and sex were found to be weak risk factors, while rural living was found to be a moderate risk factor for D fragilis, G lamblia and Cryptosporidium infections. The strongest risk factor was travel history, especially for nonendemic parasites. The retrospective analysis of six alternative protocols identified four that may be more efficient than current procedures. CONCLUSIONS: The present study demonstrated that current protocols may be redundant and can be optimized to target prevalent parasites and populations with high risk factors. PMID:25587292

Canadian Pacific Railway Investigation of Safety-Related Occurrences Protocol considered helpful by both labor and management.

DOT National Transportation Integrated Search

2006-09-01

The Federal Railroad Administration (FRA) Human Factors Research and Development (R&D) Program sponsored an Alternative Safety Measures Program designed to explore alternative methods for evaluating whether safety programs improve safety outcomes and...

Performance comparison between 8 and 14 bit-depth imaging in polarization-sensitive swept-source optical coherence tomography

NASA Astrophysics Data System (ADS)

Lu, Zenghai; Kasaragoda, Deepa K.; Matcher, Stephen J.

2011-03-01

We compare true 8 and 14 bit-depth imaging of SS-OCT and polarization-sensitive SS-OCT (PS-SS-OCT) at 1.3μm wavelength by using two hardware-synchronized high-speed data acquisition (DAQ) boards. The two DAQ boards read exactly the same imaging data for comparison. The measured system sensitivity at 8-bit depth is comparable to that for 14-bit acquisition when using the more sensitive of the available full analog input voltage ranges of the ADC. Ex-vivo structural and birefringence images of an equine tendon sample indicate no significant differences between images acquired by the two DAQ boards suggesting that 8-bit DAQ boards can be employed to increase imaging speeds and reduce storage in clinical SS-OCT/PS-SS-OCT systems. We also compare the resulting image quality when the image data sampled with the 14-bit DAQ from human finger skin is artificially bit-reduced during post-processing. However, in agreement with the results reported previously, we also observe that in our system that real-world 8-bit image shows more artifacts than the image acquired by numerically truncating to 8-bits from the raw 14-bit image data, especially in low intensity image area. This is due to the higher noise floor and reduced dynamic range of the 8-bit DAQ. One possible disadvantage is a reduced imaging dynamic range which can manifest itself as an increase in image artefacts due to strong Fresnel reflection.

Telemedicine using free voice over internet protocol (VoIP) technology.

PubMed

Miller, David J; Miljkovic, Nikola; Chiesa, Chad; Callahan, John B; Webb, Brad; Boedeker, Ben H

2011-01-01

Though dedicated videoteleconference (VTC) systems deliver high quality, low-latency audio and video for telemedical applications, they require expensive hardware and extensive infrastructure. The purpose of this study was to investigate free commercially available Voice over Internet Protocol (VoIP) software as a low cost alternative for telemedicine.

The Unusual Suspects: Myths and Misconceptions Associated with PECS

ERIC Educational Resources Information Center

Bondy, Andy

2012-01-01

The Picture Exchange Communication System (PECS) is an alternative/augmentative communication protocol designed to help children and adults with autism and related disabilities to engage in functional communication. The protocol was developed over a number of years and was based on Skinner's analysis of verbal behavior. Publications about the…

Using Open-Book Exams to Enhance Student Learning, Performance, and Motivation

ERIC Educational Resources Information Center

Green, Steve G.; Ferrante, Claudia J.; Heppard, Kurt A.

2016-01-01

This study investigated an alternative testing protocol used in an undergraduate managerial accounting course. Specifically, we assert that consistent open-book testing approaches will enhance learning and better prepare students for the real-world decision-making they will encounter. A semester-long testing protocol was executed incorporating a…

PDC bits break ground with advanced vibration mitigation

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-10-01

Advancements in PDC bit technology have resulted in the identification and characterization of different types of vibrational modes that historically have limited PDC bit performance. As a result, concepts have been developed that prevent the initiation of vibration and also mitigate its damaging effects once it occurs. This vibration-reducing concept ensures more efficient use of the energy available to a PDC bit performance. As a result, concepts have been developed that prevent the imitation of vibration and also mitigate its damaging effects once it occurs. This vibration-reducing concept ensures more efficient use of the energy available to a PDC bit,more » thereby improving its performance. This improved understanding of the complex forces affecting bit performance is driving bit customization for specific drilling programs.« less

Shuttle bit rate synchronizer. [signal to noise ratios and error analysis

NASA Technical Reports Server (NTRS)

Huey, D. C.; Fultz, G. L.

1974-01-01

A shuttle bit rate synchronizer brassboard unit was designed, fabricated, and tested, which meets or exceeds the contractual specifications. The bit rate synchronizer operates at signal-to-noise ratios (in a bit rate bandwidth) down to -5 dB while exhibiting less than 0.6 dB bit error rate degradation. The mean acquisition time was measured to be less than 2 seconds. The synchronizer is designed around a digital data transition tracking loop whose phase and data detectors are integrate-and-dump filters matched to the Manchester encoded bits specified. It meets the reliability (no adjustments or tweaking) and versatility (multiple bit rates) of the shuttle S-band communication system through an implementation which is all digital after the initial stage of analog AGC and A/D conversion.

Method for compression of binary data

DOEpatents

Berlin, Gary J.

1996-01-01

The disclosed method for compression of a series of data bytes, based on LZSS-based compression methods, provides faster decompression of the stored data. The method involves the creation of a flag bit buffer in a random access memory device for temporary storage of flag bits generated during normal LZSS-based compression. The flag bit buffer stores the flag bits separately from their corresponding pointers and uncompressed data bytes until all input data has been read. Then, the flag bits are appended to the compressed output stream of data. Decompression can be performed much faster because bit manipulation is only required when reading the flag bits and not when reading uncompressed data bytes and pointers. Uncompressed data is read using byte length instructions and pointers are read using word instructions, thus reducing the time required for decompression.

A new thermal model for bone drilling with applications to orthopaedic surgery.

PubMed

Lee, JuEun; Rabin, Yoed; Ozdoganlar, O Burak

2011-12-01

This paper presents a new thermal model for bone drilling with applications to orthopaedic surgery. The new model combines a unique heat-balance equation for the system of the drill bit and the chip stream, an ordinary heat diffusion equation for the bone, and heat generation at the drill tip, arising from the cutting process and friction. Modeling of the drill bit-chip stream system assumes an axial temperature distribution and a lumped heat capacity effect in the transverse cross-section. The new model is solved numerically using a tailor-made finite-difference scheme for the drill bit-chip stream system, coupled with a classic finite-difference method for the bone. The theoretical investigation addresses the significance of heat transfer between the drill bit and the bone, heat convection from the drill bit to the surroundings, and the effect of the initial temperature of the drill bit on the developing thermal field. Using the new model, a parametric study on the effects of machining conditions and drill-bit geometries on the resulting temperature field in the bone and the drill bit is presented. Results of this study indicate that: (1) the maximum temperature in the bone decreases with increased chip flow; (2) the transient temperature distribution is strongly influenced by the initial temperature; (3) the continued cooling (irrigation) of the drill bit reduces the maximum temperature even when the tip is distant from the cooled portion of the drill bit; and (4) the maximum temperature increases with increasing spindle speed, increasing feed rate, decreasing drill-bit diameter, increasing point angle, and decreasing helix angle. The model is expected to be useful in determination of optimum drilling conditions and drill-bit geometries. Copyright © 2011. Published by Elsevier Ltd.

Method to manufacture bit patterned magnetic recording media

DOEpatents

Raeymaekers, Bart; Sinha, Dipen N

2014-05-13

A method to increase the storage density on magnetic recording media by physically separating the individual bits from each other with a non-magnetic medium (so-called bit patterned media). This allows the bits to be closely packed together without creating magnetic "cross-talk" between adjacent bits. In one embodiment, ferromagnetic particles are submerged in a resin solution, contained in a reservoir. The bottom of the reservoir is made of piezoelectric material.

Testability Design Rating System: Testability Handbook. Volume 1

DTIC Science & Technology

1992-02-01

4-10 4.7.5 Summary of False BIT Alarms (FBA) ............................. 4-10 4.7.6 Smart BIT Technique...Circuit Board PGA Pin Grid Array PLA Programmable Logic Array PLD Programmable Logic Device PN Pseudo-Random Number PREDICT Probabilistic Estimation of...11 4.7.6 Smart BIT ( reference: RADC-TR-85-198). " Smart " BIT is a term given to BIT circuitry in a system LRU which includes dedicated processor/memory

Source-Device-Independent Ultrafast Quantum Random Number Generation.

PubMed

Marangon, Davide G; Vallone, Giuseppe; Villoresi, Paolo

2017-02-10

Secure random numbers are a fundamental element of many applications in science, statistics, cryptography and more in general in security protocols. We present a method that enables the generation of high-speed unpredictable random numbers from the quadratures of an electromagnetic field without any assumption on the input state. The method allows us to eliminate the numbers that can be predicted due to the presence of classical and quantum side information. In particular, we introduce a procedure to estimate a bound on the conditional min-entropy based on the entropic uncertainty principle for position and momentum observables of infinite dimensional quantum systems. By the above method, we experimentally demonstrated the generation of secure true random bits at a rate greater than 1.7 Gbit/s.

RC64, a Rad-Hard Many-Core High- Performance DSP for Space Applications

NASA Astrophysics Data System (ADS)

Ginosar, Ran; Aviely, Peleg; Gellis, Hagay; Liran, Tuvia; Israeli, Tsvika; Nesher, Roy; Lange, Fredy; Dobkin, Reuven; Meirov, Henri; Reznik, Dror

2015-09-01

RC64, a novel rad-hard 64-core signal processing chip targets DSP performance of 75 GMACs (16bit), 150 GOPS and 38 single precision GFLOPS while dissipating less than 10 Watts. RC64 integrates advanced DSP cores with a multi-bank shared memory and a hardware scheduler, also supporting DDR2/3 memory and twelve 3.125 Gbps full duplex high speed serial links using SpaceFibre and other protocols. The programming model employs sequential fine-grain tasks and a separate task map to define task dependencies. RC64 is implemented as a 300 MHz integrated circuit on a 65nm CMOS technology, assembled in hermetically sealed ceramic CCGA624 package and qualified to the highest space standards.

RC64, a Rad-Hard Many-Core High-Performance DSP for Space Applications

NASA Astrophysics Data System (ADS)

Ginosar, Ran; Aviely, Peleg; Liran, Tuvia; Alon, Dov; Mandler, Alberto; Lange, Fredy; Dobkin, Reuven; Goldberg, Miki

2014-08-01

RC64, a novel rad-hard 64-core signal processing chip targets DSP performance of 75 GMACs (16bit), 150 GOPS and 20 single precision GFLOPS while dissipating less than 10 Watts. RC64 integrates advanced DSP cores with a multi-bank shared memory and a hardware scheduler, also supporting DDR2/3 memory and twelve 2.5 Gbps full duplex high speed serial links using SpaceFibre and other protocols. The programming model employs sequential fine-grain tasks and a separate task map to define task dependencies. RC64 is implemented as a 300 MHz integrated circuit on a 65nm CMOS technology, assembled in hermetically sealed ceramic CCGA624 package and qualified to the highest space standards.

Measurement-Device-Independent Quantum Key Distribution over 200 km

NASA Astrophysics Data System (ADS)

Tang, Yan-Lin; Yin, Hua-Lei; Chen, Si-Jing; Liu, Yang; Zhang, Wei-Jun; Jiang, Xiao; Zhang, Lu; Wang, Jian; You, Li-Xing; Guan, Jian-Yu; Yang, Dong-Xu; Wang, Zhen; Liang, Hao; Zhang, Zhen; Zhou, Nan; Ma, Xiongfeng; Chen, Teng-Yun; Zhang, Qiang; Pan, Jian-Wei

2014-11-01

Measurement-device-independent quantum key distribution (MDIQKD) protocol is immune to all attacks on detection and guarantees the information-theoretical security even with imperfect single-photon detectors. Recently, several proof-of-principle demonstrations of MDIQKD have been achieved. Those experiments, although novel, are implemented through limited distance with a key rate less than 0.1 bit /s . Here, by developing a 75 MHz clock rate fully automatic and highly stable system and superconducting nanowire single-photon detectors with detection efficiencies of more than 40%, we extend the secure transmission distance of MDIQKD to 200 km and achieve a secure key rate 3 orders of magnitude higher. These results pave the way towards a quantum network with measurement-device-independent security.

Long-distance continuous-variable quantum key distribution with a Gaussian modulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jouguet, Paul; SeQureNet, 23 avenue d'Italie, F-75013 Paris; Kunz-Jacques, Sebastien

2011-12-15

We designed high-efficiency error correcting codes allowing us to extract an errorless secret key in a continuous-variable quantum key distribution (CVQKD) protocol using a Gaussian modulation of coherent states and a homodyne detection. These codes are available for a wide range of signal-to-noise ratios on an additive white Gaussian noise channel with a binary modulation and can be combined with a multidimensional reconciliation method proven secure against arbitrary collective attacks. This improved reconciliation procedure considerably extends the secure range of a CVQKD with a Gaussian modulation, giving a secret key rate of about 10{sup -3} bit per pulse at amore » distance of 120 km for reasonable physical parameters.« less

Randomness Amplification under Minimal Fundamental Assumptions on the Devices

NASA Astrophysics Data System (ADS)

Ramanathan, Ravishankar; Brandão, Fernando G. S. L.; Horodecki, Karol; Horodecki, Michał; Horodecki, Paweł; Wojewódka, Hanna

2016-12-01

Recently, the physically realistic protocol amplifying the randomness of Santha-Vazirani sources producing cryptographically secure random bits was proposed; however, for reasons of practical relevance, the crucial question remained open regarding whether this can be accomplished under the minimal conditions necessary for the task. Namely, is it possible to achieve randomness amplification using only two no-signaling components and in a situation where the violation of a Bell inequality only guarantees that some outcomes of the device for specific inputs exhibit randomness? Here, we solve this question and present a device-independent protocol for randomness amplification of Santha-Vazirani sources using a device consisting of two nonsignaling components. We show that the protocol can amplify any such source that is not fully deterministic into a fully random source while tolerating a constant noise rate and prove the composable security of the protocol against general no-signaling adversaries. Our main innovation is the proof that even the partial randomness certified by the two-party Bell test [a single input-output pair (u* , x* ) for which the conditional probability P (x*|u*) is bounded away from 1 for all no-signaling strategies that optimally violate the Bell inequality] can be used for amplification. We introduce the methodology of a partial tomographic procedure on the empirical statistics obtained in the Bell test that ensures that the outputs constitute a linear min-entropy source of randomness. As a technical novelty that may be of independent interest, we prove that the Santha-Vazirani source satisfies an exponential concentration property given by a recently discovered generalized Chernoff bound.

The Behavioral Intervention Technology Model: An Integrated Conceptual and Technological Framework for eHealth and mHealth Interventions

PubMed Central

Schueller, Stephen M; Montague, Enid; Burns, Michelle Nicole; Rashidi, Parisa

2014-01-01

A growing number of investigators have commented on the lack of models to inform the design of behavioral intervention technologies (BITs). BITs, which include a subset of mHealth and eHealth interventions, employ a broad range of technologies, such as mobile phones, the Web, and sensors, to support users in changing behaviors and cognitions related to health, mental health, and wellness. We propose a model that conceptually defines BITs, from the clinical aim to the technological delivery framework. The BIT model defines both the conceptual and technological architecture of a BIT. Conceptually, a BIT model should answer the questions why, what, how (conceptual and technical), and when. While BITs generally have a larger treatment goal, such goals generally consist of smaller intervention aims (the "why") such as promotion or reduction of specific behaviors, and behavior change strategies (the conceptual "how"), such as education, goal setting, and monitoring. Behavior change strategies are instantiated with specific intervention components or “elements” (the "what"). The characteristics of intervention elements may be further defined or modified (the technical "how") to meet the needs, capabilities, and preferences of a user. Finally, many BITs require specification of a workflow that defines when an intervention component will be delivered. The BIT model includes a technological framework (BIT-Tech) that can integrate and implement the intervention elements, characteristics, and workflow to deliver the entire BIT to users over time. This implementation may be either predefined or include adaptive systems that can tailor the intervention based on data from the user and the user’s environment. The BIT model provides a step towards formalizing the translation of developer aims into intervention components, larger treatments, and methods of delivery in a manner that supports research and communication between investigators on how to design, develop, and deploy BITs. PMID:24905070

The behavioral intervention technology model: an integrated conceptual and technological framework for eHealth and mHealth interventions.

PubMed

Mohr, David C; Schueller, Stephen M; Montague, Enid; Burns, Michelle Nicole; Rashidi, Parisa

2014-06-05

A growing number of investigators have commented on the lack of models to inform the design of behavioral intervention technologies (BITs). BITs, which include a subset of mHealth and eHealth interventions, employ a broad range of technologies, such as mobile phones, the Web, and sensors, to support users in changing behaviors and cognitions related to health, mental health, and wellness. We propose a model that conceptually defines BITs, from the clinical aim to the technological delivery framework. The BIT model defines both the conceptual and technological architecture of a BIT. Conceptually, a BIT model should answer the questions why, what, how (conceptual and technical), and when. While BITs generally have a larger treatment goal, such goals generally consist of smaller intervention aims (the "why") such as promotion or reduction of specific behaviors, and behavior change strategies (the conceptual "how"), such as education, goal setting, and monitoring. Behavior change strategies are instantiated with specific intervention components or "elements" (the "what"). The characteristics of intervention elements may be further defined or modified (the technical "how") to meet the needs, capabilities, and preferences of a user. Finally, many BITs require specification of a workflow that defines when an intervention component will be delivered. The BIT model includes a technological framework (BIT-Tech) that can integrate and implement the intervention elements, characteristics, and workflow to deliver the entire BIT to users over time. This implementation may be either predefined or include adaptive systems that can tailor the intervention based on data from the user and the user's environment. The BIT model provides a step towards formalizing the translation of developer aims into intervention components, larger treatments, and methods of delivery in a manner that supports research and communication between investigators on how to design, develop, and deploy BITs.

Digital Ratiometer

NASA Technical Reports Server (NTRS)

Beer, R.

1985-01-01

Small, low-cost comparator with 24-bit-precision yields ratio signal from pair of analog or digital input signals. Arithmetic logic chips (bit-slice) sample two 24-bit analog-to-digital converters approximately once every millisecond and accumulate them in two 24-bit registers. Approach readily modified to arbitrary precision.

Technology Development and Field Trials of EGS Drilling Systems at Chocolate Mountain

DOE Data Explorer

Steven Knudsen

2012-01-01

Polycrystalline diamond compact (PDC) bits are routinely used in the oil and gas industry for drilling medium to hard rock but have not been adopted for geothermal drilling, largely due to past reliability issues and higher purchase costs. The Sandia Geothermal Research Department has recently completed a field demonstration of the applicability of advanced synthetic diamond drill bits for production geothermal drilling. Two commercially-available PDC bits were tested in a geothermal drilling program in the Chocolate Mountains in Southern California. These bits drilled the granitic formations with significantly better Rate of Penetration (ROP) and bit life than the roller cone bit they are compared with. Drilling records and bit performance data along with associated drilling cost savings are presented herein. The drilling trials have demonstrated PDC bit drilling technology has matured for applicability and improvements to geothermal drilling. This will be especially beneficial for development of Enhanced Geothermal Systems whereby resources can be accessed anywhere within the continental US by drilling to deep, hot resources in hard, basement rock formations.

The Texas Thermal Interface: A real-time computer interface for an Inframetrics infrared camera

DOE Office of Scientific and Technical Information (OSTI.GOV)

Storek, D.J.; Gentle, K.W.

1996-03-01

The Texas Thermal Interface (TTI) offers an advantageous alternative to the conventional video path for computer analysis of infrared images from Inframetrics cameras. The TTI provides real-time computer data acquisition of 48 consecutive fields (version described here) with 8-bit pixels. The alternative requires time-consuming individual frame grabs from video tape with frequent loss of resolution in the D/A/D conversion. Within seconds after the event, the TTI temperature files may be viewed and processed to infer heat fluxes or other quantities as needed. The system cost is far less than commercial units which offer less capability. The system was developed formore » and is being used to measure heat fluxes to the plasma-facing components in a tokamak. {copyright} {ital 1996 American Institute of Physics.}« less

The Anoikis Effector Bit1 Inhibits EMT through Attenuation of TLE1-Mediated Repression of E-Cadherin in Lung Cancer Cells

PubMed Central

Yao, Xin; Pham, Tri; Temple, Brandi; Gray, Selena; Cannon, Cornita; Chen, Renwei; Abdel-Mageed, Asim B.; Biliran, Hector

2016-01-01

The mitochondrial Bcl-2 inhibitor of transcription 1 (Bit1) protein is part of an anoikis-regulating pathway that is selectively dependent on integrins. We previously demonstrated that the caspase-independent apoptotic effector Bit1 exerts tumor suppressive function in lung cancer in part by inhibiting anoikis resistance and anchorage-independent growth in vitro and tumorigenicity in vivo. Herein we show a novel function of Bit1 as an inhibitor cell migration and epithelial–mesenchymal transition (EMT) in the human lung adenocarcinoma A549 cell line. Suppression of endogenous Bit1 expression via siRNA and shRNA strategies promoted mesenchymal phenotypes, including enhanced fibroblastoid morphology and cell migratory potential with concomitant downregulation of the epithelial marker E-cadherin expression. Conversely, ectopic Bit1 expression in A549 cells promoted epithelial transition characterized by cuboidal-like epithelial cell phenotype, reduced cell motility, and upregulated E-cadherin expression. Specific downregulation of E-cadherin in Bit1-transfected cells was sufficient to block Bit1-mediated inhibition of cell motility while forced expression of E-cadherin alone attenuated the enhanced migration of Bit1 knockdown cells, indicating that E-cadherin is a downstream target of Bit1 in regulating cell motility. Furthermore, quantitative real-time PCR and reporter analyses revealed that Bit1 upregulates E-cadherin expression at the transcriptional level through the transcriptional regulator Amino-terminal Enhancer of Split (AES) protein. Importantly, the Bit1/AES pathway induction of E-cadherin expression involves inhibition of the TLE1-mediated repression of E-cadherin, by decreasing TLE1 corepressor occupancy at the E-cadherin promoter as revealed by chromatin immunoprecipitation assays. Consistent with its EMT inhibitory function, exogenous Bit1 expression significantly suppressed the formation of lung metastases of A549 cells in an in vivo experimental metastasis model. Taken together, our studies indicate Bit1 is an inhibitor of EMT and metastasis in lung cancer and hence can serve as a molecular target in curbing lung cancer aggressiveness. PMID:27655370

The Decremental Protocol as an Alternative Protocol to Measure Maximal Oxygen Consumption in Athletes.

PubMed

Taylor, Katrina; Seegmiller, Jeffrey; Vella, Chantal A

2016-11-01

To determine whether a decremental protocol could elicit a higher maximal oxygen consumption (VO 2 max) than an incremental protocol in trained participants. A secondary aim was to examine whether cardiac-output (Q) and stroke-volume (SV) responses differed between decremental and incremental protocols in this sample. Nineteen runners/triathletes were randomized to either the decremental or incremental group. All participants completed an initial incremental VO 2 max test on a treadmill, followed by a verification phase. The incremental group completed 2 further incremental tests. The decremental group completed a second VO 2 max test using the decremental protocol, based on their verification phase. The decremental group then completed a final incremental test. During each test, VO 2 , ventilation, and heart rate were measured, and cardiac variables were estimated with thoracic bioimpedance. Repeated-measures analysis of variance was conducted with an alpha level set at .05. There were no significant main effects for group (P = .37) or interaction (P = .10) over time (P = .45). VO 2 max was similar between the incremental (57.29 ± 8.94 mL · kg -1 · min -1 ) and decremental (60.82 ± 8.49 mL · kg -1 · min -1 ) groups over time. Furthermore, Q and SV were similar between the incremental (Q 22.72 ± 5.85 L/min, SV 119.64 ± 33.02 mL/beat) and decremental groups (Q 20.36 ± 4.59 L/min, SV 109.03 ± 24.27 mL/beat) across all 3 trials. The findings suggest that the decremental protocol does not elicit higher VO 2 max than an incremental protocol but may be used as an alternative protocol to measure VO 2 max in runners and triathletes.

Robust quantum secure direct communication and authentication protocol against decoherence noise based on six-qubit DF state

NASA Astrophysics Data System (ADS)

Chang, Yan; Zhang, Shi-Bin; Yan, Li-Li; Han, Gui-Hua

2015-05-01

By using six-qubit decoherence-free (DF) states as quantum carriers and decoy states, a robust quantum secure direct communication and authentication (QSDCA) protocol against decoherence noise is proposed. Four six-qubit DF states are used in the process of secret transmission, however only the |0‧⟩ state is prepared. The other three six-qubit DF states can be obtained by permuting the outputs of the setup for |0‧⟩. By using the |0‧⟩ state as the decoy state, the detection rate and the qubit error rate reach 81.3%, and they will not change with the noise level. The stability and security are much higher than those of the ping-pong protocol both in an ideal scenario and a decoherence noise scenario. Even if the eavesdropper measures several qubits, exploiting the coherent relationship between these qubits, she can gain one bit of secret information with probability 0.042. Project supported by the National Natural Science Foundation of China (Grant No. 61402058), the Science and Technology Support Project of Sichuan Province of China (Grant No. 2013GZX0137), the Fund for Young Persons Project of Sichuan Province of China (Grant No. 12ZB017), and the Foundation of Cyberspace Security Key Laboratory of Sichuan Higher Education Institutions, China (Grant No. szjj2014-074).

Quantum communication and information processing

NASA Astrophysics Data System (ADS)

Beals, Travis Roland

Quantum computers enable dramatically more efficient algorithms for solving certain classes of computational problems, but, in doing so, they create new problems. In particular, Shor's Algorithm allows for efficient cryptanalysis of many public-key cryptosystems. As public key cryptography is a critical component of present-day electronic commerce, it is crucial that a working, secure replacement be found. Quantum key distribution (QKD), first developed by C.H. Bennett and G. Brassard, offers a partial solution, but many challenges remain, both in terms of hardware limitations and in designing cryptographic protocols for a viable large-scale quantum communication infrastructure. In Part I, I investigate optical lattice-based approaches to quantum information processing. I look at details of a proposal for an optical lattice-based quantum computer, which could potentially be used for both quantum communications and for more sophisticated quantum information processing. In Part III, I propose a method for converting and storing photonic quantum bits in the internal state of periodically-spaced neutral atoms by generating and manipulating a photonic band gap and associated defect states. In Part II, I present a cryptographic protocol which allows for the extension of present-day QKD networks over much longer distances without the development of new hardware. I also present a second, related protocol which effectively solves the authentication problem faced by a large QKD network, thus making QKD a viable, information-theoretic secure replacement for public key cryptosystems.

Free-Space Quantum Key Distribution using Polarization Entangled Photons

NASA Astrophysics Data System (ADS)

Kurtsiefer, Christian

2007-06-01

We report on a complete experimental implementation of a quantum key distribution protocol through a free space link using polarization-entangled photon pairs from a compact parametric down-conversion source [1]. Based on a BB84-equivalent protocol, we generated without interruption over 10 hours a secret key free-space optical link distance of 1.5 km with a rate up to 950 bits per second after error correction and privacy amplification. Our system is based on two time stamp units and relies on no specific hardware channel for coincidence identification besides an IP link. For that, initial clock synchronization with an accuracy of better than 2 ns is achieved, based on a conventional NTP protocol and a tiered cross correlation of time tags on both sides. Time tags are used to servo a local clock, allowing a streamed measurement on correctly identified photon pairs. Contrary to the majority of quantum key distribution systems, this approach does not require a trusted large-bandwidth random number generator, but integrates that into the physical key generation process. We discuss our current progress of implementing a key distribution via an atmospherical link during daylight conditions, and possible attack scenarios on a physical timing information side channel to a entanglement-based key distribution system. [1] I. Marcikic, A. Lamas-Linares, C. Kurtsiefer, Appl. Phys. Lett. 89, 101122 (2006).

New On-board Microprocessors

NASA Astrophysics Data System (ADS)

Weigand, R.

Two new processor devices have been developed for the use on board of spacecrafts. An 8-bit 8032-microcontroller targets typical controlling applications in instruments and sub-systems, or could be used as a main processor on small satellites, whereas the LEON 32-bit SPARC processor can be used for high performance controlling and data processing tasks. The ADV80S32 is fully compliant to the Intel 80x1 architecture and instruction set, extended by additional peripherals, 512 bytes on-chip RAM and a bootstrap PROM, which allows downloading the application software using the CCSDS PacketWire pro- tocol. The memory controller provides a de-multiplexed address/data bus, and allows to access up to 16 MB data and 8 MB program RAM. The peripherals have been de- signed for the specific needs of a spacecraft, such as serial interfaces compatible to RS232, PacketWire and TTC-B-01, counters/timers for extended duration and a CRC calculation unit accelerating the CCSDS TM/TC protocol. The 0.5 um Atmel manu- facturing technology (MG2RT) provides latch-up and total dose immunity; SEU fault immunity is implemented by using SEU hardened Flip-Flops and EDAC protection of internal and external memories. The maximum clock frequency of 20 MHz allows a processing power of 3 MIPS. Engineering samples are available. For SW develop- ment, various SW packages for the 8051 architecture are on the market. The LEON processor implements a 32-bit SPARC V8 architecture, including all the multiply and divide instructions, complemented by a floating-point unit (FPU). It includes several standard peripherals, such as timers/watchdog, interrupt controller, UARTs, parallel I/Os and a memory controller, allowing to use 8, 16 and 32 bit PROM, SRAM or memory mapped I/O. With on-chip separate instruction and data caches, almost one instruction per clock cycle can be reached in some applications. A 33-MHz 32-bit PCI master/target interface and a PCI arbiter allow operating the device in a plug-in card (for SW development on PC etc.), or to consider using it as a PCI master controller in an on-board system. Advanced SEU fault tolerance is in- troduced by design, using triple modular redundancy (TMR) flip-flops for all registers and EDAC protection for all memories. The device will be manufactured in a radia- tion hard Atmel 0.25 um technology, targeting 100 MHz processor clock frequency. The non fault-tolerant LEON processor VHDL model is available as free source code, and the SPARC architecture is a well-known industry standard. Therefore, know-how, software tools and operating systems are widely available.

Effects of size on three-cone bit performance in laboratory drilled shale

DOE Office of Scientific and Technical Information (OSTI.GOV)

Black, A.D.; DiBona, B.G.; Sandstrom, J.L.

1982-09-01

The effects of size on the performance of 3-cone bits were measured during laboratory drilling tests in shale at simulated downhole conditions. Four Reed HP-SM 3-cone bits with diameters of 6 1/2, 7 7/8, 9 1/2 and 11 inches were used to drill Mancos shale with water-based mud. The tests were conducted at constant borehole pressure, two conditions of hydraulic horsepower per square inch of bit area, three conditions of rotary speed and four conditions of weight-on-bit per inch of bit diameter. The resulting penetration rates and torques were measured. Statistical techniques were used to analyze the data.

LSB-based Steganography Using Reflected Gray Code for Color Quantum Images

NASA Astrophysics Data System (ADS)

Li, Panchi; Lu, Aiping

2018-02-01

At present, the classical least-significant-bit (LSB) based image steganography has been extended to quantum image processing. For the existing LSB-based quantum image steganography schemes, the embedding capacity is no more than 3 bits per pixel. Therefore, it is meaningful to study how to improve the embedding capacity of quantum image steganography. This work presents a novel LSB-based steganography using reflected Gray code for colored quantum images, and the embedding capacity of this scheme is up to 4 bits per pixel. In proposed scheme, the secret qubit sequence is considered as a sequence of 4-bit segments. For the four bits in each segment, the first bit is embedded in the second LSB of B channel of the cover image, and and the remaining three bits are embedded in LSB of RGB channels of each color pixel simultaneously using reflected-Gray code to determine the embedded bit from secret information. Following the transforming rule, the LSB of stego-image are not always same as the secret bits and the differences are up to almost 50%. Experimental results confirm that the proposed scheme shows good performance and outperforms the previous ones currently found in the literature in terms of embedding capacity.

Quantization of Gaussian samples at very low SNR regime in continuous variable QKD applications

NASA Astrophysics Data System (ADS)

Daneshgaran, Fred; Mondin, Marina

2016-09-01

The main problem for information reconciliation in continuous variable Quantum Key Distribution (QKD) at low Signal to Noise Ratio (SNR) is quantization and assignment of labels to the samples of the Gaussian Random Variables (RVs) observed at Alice and Bob. Trouble is that most of the samples, assuming that the Gaussian variable is zero mean which is de-facto the case, tend to have small magnitudes and are easily disturbed by noise. Transmission over longer and longer distances increases the losses corresponding to a lower effective SNR exasperating the problem. This paper looks at the quantization problem of the Gaussian samples at very low SNR regime from an information theoretic point of view. We look at the problem of two bit per sample quantization of the Gaussian RVs at Alice and Bob and derive expressions for the mutual information between the bit strings as a result of this quantization. The quantization threshold for the Most Significant Bit (MSB) should be chosen based on the maximization of the mutual information between the quantized bit strings. Furthermore, while the LSB string at Alice and Bob are balanced in a sense that their entropy is close to maximum, this is not the case for the second most significant bit even under optimal threshold. We show that with two bit quantization at SNR of -3 dB we achieve 75.8% of maximal achievable mutual information between Alice and Bob, hence, as the number of quantization bits increases beyond 2-bits, the number of additional useful bits that can be extracted for secret key generation decreases rapidly. Furthermore, the error rates between the bit strings at Alice and Bob at the same significant bit level are rather high demanding very powerful error correcting codes. While our calculations and simulation shows that the mutual information between the LSB at Alice and Bob is 0.1044 bits, that at the MSB level is only 0.035 bits. Hence, it is only by looking at the bits jointly that we are able to achieve a mutual information of 0.2217 bits which is 75.8% of maximum achievable. The implication is that only by coding both MSB and LSB jointly can we hope to get close to this 75.8% limit. Hence, non-binary codes are essential to achieve acceptable performance.

Hey! A Tick Bit Me!

MedlinePlus

... Staying Safe Videos for Educators Search English Español Hey! A Tick Bit Me! KidsHealth / For Kids / Hey! A Tick Bit Me! Print en español ¡Ay! ¡ ... tick collar. More on this topic for: Kids Hey! A Brown Recluse Spider Bit Me! Hey! A ...

Core drill's bit is replaceable without withdrawal of drill stem - A concept

NASA Technical Reports Server (NTRS)

Rushing, F. C.; Simon, A. B.

1970-01-01

Drill bit is divided into several sectors. When collapsed, the outside diameter is forced down the drill stem, when it reaches bottom the sectors are forced outward and form a cutting bit. A dulled bit is retracted by reversal of this procedure.

Are exergames promoting mobility an attractive alternative to conventional self-regulated exercises for elderly people in a rehabilitation setting? Study protocol of a randomized controlled trial.

PubMed

Hasselmann, Viviane; Oesch, Peter; Fernandez-Luque, Luis; Bachmann, Stefan

2015-09-07

Maintaining mobility in elderly persons has become a primary goal within healthcare services. In older adults, exercise programs significantly reduce the risk of falling and death. Long-lasting and high-intensive multi-component exercises are most effective. In a rehabilitation setting, self-regulated exercises are conventionally taught by physiotherapists, using handouts. However, the adherence of elderly persons to executing these self-administered programs varies considerably. They are often considered tedious and boring, and thus prematurely stopped. The primary aim of this clinical trial is to determine whether elderly persons in a rehabilitation setting show higher adherence to self-regulated training when using exergames than when performing conventional exercises. The second objective is to explore which mode of exercise leads to greater improvement in balance performance. The study consists of a single blind, stratified, randomized control trial with two parallel groups. Once included, study participants will be stratified according to their balance and computer skills and randomly allocated to self-regulated training with conventional exercise programs or with exergames played with the Windows Kinect® sensor and FitBit® pedometer. In both groups, self-administered exercise programs will be taught by experienced physiotherapists and performed at the patient's own discretion during the ten days of intervention. The primary outcome is the performed daily training volume, collected by the participants in a logbook. Secondary outcomes are objective and subjective balance skills measured by an activity tracker and the Fall Efficacy Scale self-administered questionnaire. Both assessments will be performed at pre- and post-intervention. According to the available literature, this study is the first to compare conventional self-regulated exercises with exergames among older patients in a rehabilitation setting. Results of this study will contribute to our understanding of its motivational potential on exercise adherence in elderly persons and provide more insight into the potential effectiveness of exergames promoting mobility. The present clinical study has been registered on ClinicalTrials.gov under the identifier number: NCT02077049. The detailed trial protocol can be accessed online on: NCT02077049.

Lathe tool bit and holder for machining fiberglass materials

NASA Technical Reports Server (NTRS)

Winn, L. E. (Inventor)

1972-01-01

A lathe tool and holder combination for machining resin impregnated fiberglass cloth laminates is described. The tool holder and tool bit combination is designed to accommodate a conventional carbide-tipped, round shank router bit as the cutting medium, and provides an infinite number of cutting angles in order to produce a true and smooth surface in the fiberglass material workpiece with every pass of the tool bit. The technique utilizes damaged router bits which ordinarily would be discarded.

High speed, real-time, camera bandwidth converter

DOEpatents

Bower, Dan E; Bloom, David A; Curry, James R

2014-10-21

Image data from a CMOS sensor with 10 bit resolution is reformatted in real time to allow the data to stream through communications equipment that is designed to transport data with 8 bit resolution. The incoming image data has 10 bit resolution. The communication equipment can transport image data with 8 bit resolution. Image data with 10 bit resolution is transmitted in real-time, without a frame delay, through the communication equipment by reformatting the image data.

Method for compression of binary data

DOEpatents

Berlin, G.J.

1996-03-26

The disclosed method for compression of a series of data bytes, based on LZSS-based compression methods, provides faster decompression of the stored data. The method involves the creation of a flag bit buffer in a random access memory device for temporary storage of flag bits generated during normal LZSS-based compression. The flag bit buffer stores the flag bits separately from their corresponding pointers and uncompressed data bytes until all input data has been read. Then, the flag bits are appended to the compressed output stream of data. Decompression can be performed much faster because bit manipulation is only required when reading the flag bits and not when reading uncompressed data bytes and pointers. Uncompressed data is read using byte length instructions and pointers are read using word instructions, thus reducing the time required for decompression. 5 figs.

Method and apparatus for high speed data acquisition and processing

DOEpatents

Ferron, J.R.

1997-02-11

A method and apparatus are disclosed for high speed digital data acquisition. The apparatus includes one or more multiplexers for receiving multiple channels of digital data at a low data rate and asserting a multiplexed data stream at a high data rate, and one or more FIFO memories for receiving data from the multiplexers and asserting the data to a real time processor. Preferably, the invention includes two multiplexers, two FIFO memories, and a 64-bit bus connecting the FIFO memories with the processor. Each multiplexer receives four channels of 14-bit digital data at a rate of up to 5 MHz per channel, and outputs a data stream to one of the FIFO memories at a rate of 20 MHz. The FIFO memories assert output data in parallel to the 64-bit bus, thus transferring 14-bit data values to the processor at a combined rate of 40 MHz. The real time processor is preferably a floating-point processor which processes 32-bit floating-point words. A set of mask bits is prestored in each 32-bit storage location of the processor memory into which a 14-bit data value is to be written. After data transfer from the FIFO memories, mask bits are concatenated with each stored 14-bit data value to define a valid 32-bit floating-point word. Preferably, a user can select any of several modes for starting and stopping direct memory transfers of data from the FIFO memories to memory within the real time processor, by setting the content of a control and status register. 15 figs.

Method and apparatus for high speed data acquisition and processing

DOEpatents

Ferron, John R.

1997-01-01

A method and apparatus for high speed digital data acquisition. The apparatus includes one or more multiplexers for receiving multiple channels of digital data at a low data rate and asserting a multiplexed data stream at a high data rate, and one or more FIFO memories for receiving data from the multiplexers and asserting the data to a real time processor. Preferably, the invention includes two multiplexers, two FIFO memories, and a 64-bit bus connecting the FIFO memories with the processor. Each multiplexer receives four channels of 14-bit digital data at a rate of up to 5 MHz per channel, and outputs a data stream to one of the FIFO memories at a rate of 20 MHz. The FIFO memories assert output data in parallel to the 64-bit bus, thus transferring 14-bit data values to the processor at a combined rate of 40 MHz. The real time processor is preferably a floating-point processor which processes 32-bit floating-point words. A set of mask bits is prestored in each 32-bit storage location of the processor memory into which a 14-bit data value is to be written. After data transfer from the FIFO memories, mask bits are concatenated with each stored 14-bit data value to define a valid 32-bit floating-point word. Preferably, a user can select any of several modes for starting and stopping direct memory transfers of data from the FIFO memories to memory within the real time processor, by setting the content of a control and status register.

Hey! A Mosquito Bit Me! (For Kids)

MedlinePlus

... Staying Safe Videos for Educators Search English Español Hey! A Mosquito Bit Me! KidsHealth / For Kids / Hey! A Mosquito Bit Me! Print en español ¡Ay! ¡ ... your skin. More on this topic for: Kids Hey! A Flea Bit Me! Hey! A Scorpion Stung ...

Effectiveness of sequential automatic-manual home respiratory polygraphy scoring.

PubMed

Masa, Juan F; Corral, Jaime; Pereira, Ricardo; Duran-Cantolla, Joaquin; Cabello, Marta; Hernández-Blasco, Luis; Monasterio, Carmen; Alonso-Fernandez, Alberto; Chiner, Eusebi; Vázquez-Polo, Francisco-José; Montserrat, Jose M

2013-04-01

Automatic home respiratory polygraphy (HRP) scoring functions can potentially confirm the diagnosis of sleep apnoea-hypopnoea syndrome (SAHS) (obviating technician scoring) in a substantial number of patients. The result would have important management and cost implications. The aim of this study was to determine the diagnostic cost-effectiveness of a sequential HRP scoring protocol (automatic and then manual for residual cases) compared with manual HRP scoring, and with in-hospital polysomnography. We included suspected SAHS patients in a multicentre study and assigned them to home and hospital protocols at random. We constructed receiver operating characteristic (ROC) curves for manual and automatic scoring. Diagnostic agreement for several cut-off points was explored and costs for two equally effective alternatives were calculated. Of 366 randomised patients, 348 completed the protocol. Manual scoring produced better ROC curves than automatic scoring. There was no sensitive automatic or subsequent manual HRP apnoea-hypopnoea index (AHI) cut-off point. The specific cut-off points for automatic and subsequent manual HRP scorings (AHI >25 and >20, respectively) had a specificity of 93% for automatic and 94% for manual scorings. The costs of manual protocol were 9% higher than sequential HRP protocol; these were 69% and 64%, respectively, of the cost of the polysomnography. A sequential HRP scoring protocol is a cost-effective alternative to polysomnography, although with limited cost savings compared to HRP manual scoring.

A cooled CCD camera-based protocol provides an effective solution for in vitro monitoring of luciferase.

PubMed

Afshari, Amirali; Uhde-Stone, Claudia; Lu, Biao

2015-03-13

Luciferase assay has become an increasingly important technique to monitor a wide range of biological processes. However, the mainstay protocols require a luminometer to acquire and process the data, therefore limiting its application to specialized research labs. To overcome this limitation, we have developed an alternative protocol that utilizes a commonly available cooled charge-coupled device (CCCD), instead of a luminometer for data acquiring and processing. By measuring activities of different luciferases, we characterized their substrate specificity, assay linearity, signal-to-noise levels, and fold-changes via CCCD. Next, we defined the assay parameters that are critical for appropriate use of CCCD for different luciferases. To demonstrate the usefulness in cultured mammalian cells, we conducted a case study to examine NFκB gene activation in response to inflammatory signals in human embryonic kidney cells (HEK293 cells). We found that data collected by CCCD camera was equivalent to those acquired by luminometer, thus validating the assay protocol. In comparison, The CCCD-based protocol is readily amenable to live-cell and high-throughput applications, offering fast simultaneous data acquisition and visual and quantitative data presentation. In conclusion, the CCCD-based protocol provides a useful alternative for monitoring luciferase reporters. The wide availability of CCCD will enable more researchers to use luciferases to monitor and quantify biological processes. Copyright © 2015 Elsevier Inc. All rights reserved.

A Study of a Standard BIT Circuit.

DTIC Science & Technology

1977-02-01

IENDED BIT APPROACHES FOR QED MODULES AND APPLICATION OF THE ANALYTIC MEASURES 36 4.1 Built-In-Test for Memory Class Modules 37 4.1.1 Random Access...Implementation 68 4.1.5.5 Criti cal Parameters 68 4.1.5.6 QED Module Test Equipment Requirements 68 4.1.6 Application of Analytic Measures to the...Microprocessor BIT Techniques.. 121 4.2.9 Application of Analytic Measures to the Recommended BIT App roaches 125 4.2.10 Process Class BIT by Partial

New PDC bit optimizes drilling performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Besson, A.; Gudulec, P. le; Delwiche, R.

1996-05-01

The lithology in northwest Argentina contains a major section where polycrystalline diamond compact (PDC) bits have not succeeded in the past. The section consists of dense shales and cemented sandstone stringers with limestone laminations. Conventional PDC bits experienced premature failures in the section. A new generation PDC bit tripled rate of penetration (ROP) and increased by five times the potential footage per bit. Recent improvements in PDC bit technology that enabled the improved performance include: the ability to control the PDC cutter quality; use of an advanced cutter lay out defined by 3D software; using cutter face design code formore » optimized cleaning and cooling; and, mastering vibration reduction features, including spiraled blades.« less