309 research outputs found

    Elucidation of subfamily segregation and intramolecular coevolution of the olfactomedin-like proteins by comprehensive phylogenetic analysis and gene expression pattern assessment

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    AbstractThe categorization of genes by structural distinctions relevant to biological characteristics is very important for understanding of gene functions and predicting functional implications of uncharacterized genes. It was absolutely necessary to deploy an effective and efficient strategy to deal with the complexity of the large olfactomedin-like (OLF) gene family sharing sequence similarity but playing diversified roles in many important biological processes, as the simple highest-hit homology analysis gave incomprehensive results and led to inappropriate annotation for some uncharacterized OLF members. In light of evolutionary information that may facilitate the classification of the OLF family and proper association of novel OLF genes with characterized homologs, we performed phylogenetic analysis on all 116 OLF proteins currently available, including two novel members cloned by our group. The OLF family segregated into seven subfamilies and members with similar domain compositions or functional properties all fell into relevant subfamilies. Furthermore, our Northern blot analysis and previous studies revealed that the typical human OLF members in each subfamily exhibited tissue-specific expression patterns, which in turn supported the segregation of the OLF subfamilies with functional divergence. Interestingly, the phylogenetic tree topology for the OLF domains alone was almost identical with that of the full-length tree representing the unique phylogenetic feature of full-length OLF proteins and their particular domain compositions. Moreover, each of the major functional domains of OLF proteins kept the same phylogenetic feature in defining similar topology of the tree. It indicates that the OLF domain and the various domains in flanking non-OLF regions have coevolved and are likely to be functionally interdependent. Expanded by a plausible gene duplication and domain couplings scenario, the OLF family comprises seven evolutionarily and functionally distinct subfamilies, in which each member shares similar structural and functional characteristics including the composition of coevolved and interdependent domains. The phylogenetically classified and preliminarily assessed subfamily framework may greatly facilitate the studying on the OLF proteins. Furthermore, it also demonstrated a feasible and reliable strategy to categorize novel genes and predict the functional implications of uncharacterized proteins based on the comprehensive phylogenetic classification of the subfamilies and their relevance to preliminary functional characteristics

    On the Security of an Improved Password Authentication Scheme Based on ECC

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    The design of secure remote user authentication schemes for mobile applications is still an open and quite challenging problem, though many schemes have been published lately. Recently, Islam and Biswas pointed out that Lin and Hwang et al.\u27s password-based authentication scheme is vulnerable to various attacks, and then presented an improved scheme based on elliptic curve cryptography (ECC) to overcome the drawbacks. Based on heuristic security analysis, Islam and Biswas claimed that their scheme is secure and can withstand all related attacks. In this paper, however, we show that Islam and Biswas\u27s scheme cannot achieve the claimed security goals and report its flaws: (1) It is vulnerable to offline password guessing attack, stolen verifier attack and denial of service (DoS) attack; (2) It fails to preserve user anonymity. The cryptanalysis demonstrates that the scheme under study is unfit for practical use

    Users Collaborative Mix-Zone to Resist the Query Content and Time Interval Correlation Attacks

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    In location-based services of continuous query, it is easier than snapshot to confirm whether a location belongs to a particular user, because sole location can be composed into a trajectory by profile correlation. In order to cut off the correlation and disturb the sub-trajectory, an un-detective region called mix-zone was proposed. However, at the time of this writing, the existing algorithms of this type mainly focus on the profiles of ID, passing time, transition probability, mobility patterns as well as road characteristics. In addition, there is still no standard way of coping with attacks of correlating each location by mining out query content and time interval from the sub-trajectory. To cope with such types of attack, users have to generalize their query contents and time intervals similarity. Hence, this paper first provided an attack model to simulate the adversary correlating the real location with a higher probability of query content and time interval similarity. Then a user collaboration mix-zone (CoMix) that can generalize these two types of profiles is proposed, so as to achieve location privacy. In CoMix, each user shares the common profile set to lowering the probability of success opponents to get the actual position through the correlation of location. Thirdly, entropy is utilized to measure the level of privacy preservation. At last, this paper further verifies the effectiveness and efficiency of the proposed algorithm by experimental evaluations

    Study on Complex Products Job-shop Scheduling System Based on MES

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    Various random disturbances that happen in the process of complex products (ship) production cannot feedback timely, and the plans of job-shop operation are too rough to instruct job-shop production. The purpose of this study is to solve the problems above, help the course of complex products (ship) job-shop production runs orderly and efficiently, and improve the job-shop on-site management level. In this paper, we proposed complex products job-shop scheduling system based on MES. The system adopts six-level, refined plan and scheduling mechanism. Its key part is the job-shop scheduling model with man-machine coordinated mechanism. What’s more, an improved Genetic Algorithm based on TOC is proposed to make the optimized algorithm module of the system more scientific and effective. Key words: Complex Products; MES; Job-shop Scheduling System; Man-machine Coordinated Mechanism; Genetic Algorithm Résumé: Diverses perturbations qui se produisent au hasard dans le processus de production des produits complexes (navire) ne peuvent pas être apperçues en temps opportun, et les plans de l'opération des ateliers sont trop approximatifs pour guider la production. Le but de cette étude consiste à résoudre les problèmes ci-dessus, rendre le cours de la production des produits complexes (ship) dans les ateliers ordonné et efficace et améliorer le niveau de gestion sur place. Dans cet article, nous avons proposé le système de planning des ateliers de produits complexes basé sur MES. Le système contient six niveaux de programmation raffinée et de mécanismes de planning. Son élément essentiel est le modèle de programmation avec les mécanismes de coordination homme-machine. De plus, un algorithme génétique amélioré basé sur TOC est également proposé de rendre le module de l'algorithme du système optimisé plus scientifique et efficace. Mots-clés: produits complexes; MES; système de planning des ateliers; mécanismes de coordination homme-machine; algorithme génétique 摘要:針對目前複雜產品(船舶)生產過程中所出現的各種隨機擾動不能得到及時回饋,以及車間作業計畫粗略難以直接指導車間生產的現狀,本文提出基於 MES的複雜產品車間作業調度系統。該系統採用逐層細化的五級計畫與調度機制,以人機協同的車間作業調度模型為核心,通過改進基於 TOC的遺傳演算法,使系統的演算法模組優化性能更具有科學性和操作性。該系統有助於實現複雜產品(船舶)車間生產過程的有序運作,從而提高生產車間的現場管理水準。 關鍵字:複雜產品; MES;車間作業調度;人機協同;遺傳演算

    Measurement-device-independent quantum key distribution with uncharacterized qubit sources

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    Measurement-device-independent quantum key distribution (MDIQKD) is proposed to be secure against any possible detection attacks. The security of the original proposal relies on the assumption that the legitimate users can fully characterize the encoding systems including sources. Here, we propose a MDIQKD protocol where we allow uncharacterized encoding systems as long as qubit sources are used. A security proof of the MDIQKD protocol is presented that does not need the knowledge of the encoding states. Simulation results show that the scheme is practical

    Robust Smart Card based Password Authentication Scheme against Smart Card Security Breach

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    As the most prevailing two-factor authentication mechanism, smart card based password authentication has been a subject of intensive research in the past decade and hundreds of this type of schemes have been proposed. However, most of them were found severely flawed, especially prone to the smart card loss problem, shortly after they were first put forward, no matter the security is heuristically analyzed or formally proved. In SEC\u2712, Wang pointed out that, the main cause of this issue is attributed to the lack of an appropriate security model to fully identify the practical threats. To address the issue, Wang presented three kinds of security models, namely Type I, II and III, and further proposed four concrete schemes, only two of which, i.e. PSCAV and PSCAb, are claimed to be secure under the harshest model, i.e. Type III security model. However, in this paper, we demonstrate that PSCAV still cannot achieve the claimed security goals and is vulnerable to an offline password guessing attack and other attacks in the Type III security mode, while PSCAb has several practical pitfalls. As our main contribution, a robust scheme is presented to cope with the aforementioned defects and it is proven to be secure in the random oracle model. Moreover, the analysis demonstrates that our scheme meets all the proposed criteria and eliminates several hard security threats that are difficult to be tackled at the same time in previous scholarship

    Mismatched-basis statistics enable quantum key distribution with uncharacterized qubit sources

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    In the postprocessing of quantum key distribution, the raw key bits from the mismatched-basis measurements, where two parties use different bases, are normally discarded. Here, we propose a postprocessing method that exploits measurement statistics from mismatched-basis cases, and prove that incorporating these statistics enables uncharacterized qubit sources to be used in the measurement-device-independent quantum key distribution protocol and the Bennett-Brassard 1984 protocol, a case which is otherwise impossible.Comment: Part of this article contains a significant improvement over arXiv:1309.381
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