Partial identities as a foundation for trust and reputation

This paper explores the relationships between the hard security concepts of identity and privacy on the one hand, and the soft security concepts of trust and reputation on the other hand. We specifically focus on two vulnerabilities that current trust and reputation systems have: the change of identity and multiple identities problems. As a result, we provide a privacy preserving solution to these vulnerabilities which integrates the explored relationships among identity, privacy, trust and reputation. We also provide a prototype of our solution to these vulnerabilities and an application scenario.     

Communication and organization: an empirical study of discussion ininspection meetings

This paper describes an empirical study that addresses the issue of communication among members of a software development organization. In particular, data was collected concerning code inspections in one software development project. The question of interest is whether or not organizational structure (the network of relationships between developers) has an effect on the amount of effort expended on communication between developers. The independent variables in this study are various attributes of the organizational structure in which the inspection participants work. The dependent variables are measures of the communication effort expended in various parts of the code inspection process, focusing on the inspection meeting. Both quantitative and qualitative methods were used, including participant observation, structured interviews, generation of hypotheses from field notes, statistical tests of relationships, and interpretation of results with qualitative anecdotes. The study results show that past and present working relationships between inspection participants affect the amount of meeting time spent in different types of discussion, thus affecting the overall inspection meeting length. Reporting relationships and physical proximity also have an effect. The contribution of the study is a set of well-supported hypotheses for further investigation     

Data positioning as an instrument of constructive data compression

A fundamentally new algorithm for data compression is considered. A theoretical basis is provided for the formation, modification, and conversion of data positions aimed at their reversible compression. The specifics are described of a method development based on structure encryption, i.e., reformatting the architecture of the compressed data alphabet based on the positionality and conditionality properties of the compression level and the structural numbering of the reformatted alphabet??s architecture in a positional multilevel space. We substantiate the principle of redundancy reduction due to the following: the simultaneous modification of the positions inhibiting the appearance of noninteger values of new positions and constraints on the digit capacity of the elements in positioning arrays, the identification of the carriers of stabilizing elements in the digital space, and the reduction of the positions with code combinations in the course of the array processing. A particular case of a data conversion protocol is presented. Problems are solved of combining the principles of data reversibility and supercompression both in the modes of single and multiple use of one and the same encryption scenario. The cost of the positioning processes and their influence on the efficiency of the processes of the data encoding and decoding have been determined.     

Modeling the web as a hypergraph to compute page reputation

In this work we propose a model to represent the web as a directed hypergraph (instead of a graph), where links connect pairs of disjointed sets of pages. The web hypergraph is derived from the web graph by dividing the set of pages into non-overlapping blocks and using the links between pages of distinct blocks to create hyperarcs. A hyperarc connects a block of pages to a single page, in order to provide more reliable information for link analysis. We use the hypergraph model to create the hypergraph versions of the Pagerank and Indegree algorithms, referred to as HyperPagerank and HyperIndegree, respectively. The hypergraph is derived from the web graph by grouping pages by two different partition criteria: grouping together the pages that belong to the same web host or to the same web domain. We compared the original page-based algorithms with the host-based and domain-based versions of the algorithms, considering a combination of the page reputation, the textual content of the pages and the anchor text. Experimental results using three distinct web collections show that the HyperPagerank and HyperIndegree algorithms may yield better results than the original graph versions of the Pagerank and Indegree algorithms. We also show that the hypergraph versions of the algorithms were slightly less affected by noise links and spamming.     

Fusing and mining opinions for reputation generation

The Internet provides a convenient platform for people to freely share their opinions on any entities. The opinions expressed in natural languages carry the subjective attitudes and preferences of humans. They represent the public perspectives on any entity, thus impact user decisions and behaviors in some way. Therefore, opinions have been recognized as useful and valuable pieces of information for reputation generation. Fusing and mining opinions offer a promising approach to extract reputation information and track public perspectives. However, the literature lacks studies on this topic. In this paper, we propose a novel reputation generation approach based on opinion fusion and mining. In our approach, opinions are filtered to eliminate unrelated ones, and then grouped into a number of fused principal opinion sets that contain opinions with a similar or the same attitude or preference. By aggregating the ratings attached to the fused opinions, we normalize the reputation of an entity. Meanwhile, various types of recommendations can be generated based on relationships among opinions. To offer sufficient reputation information to users, we also propose a new way of reputation visualization. It shows the details of opinion fusing and mining results, such as the normalized reputation value, principal opinions with popularity and other statistics. Experimental results coming from an analysis of big real-world data collected from several popular commercial websites in both English and Chinese demonstrate the generality and accuracy of the proposed approach, especially the effectiveness of opinion filtering for reputation generation. A small-scale real-world user study further quantifies the user acceptance of the developed reputation visualization method. In the sequel, this implies that the proposed approach can be applied in practice to generate reputation.     

On the analysis of reputation for agent-based web services

Maintaining sound reputation requires robust control and investigation. In this paper, we analyze a reputation mechanism that objectively maintains accurate reputation evaluation of selfish agent-based web services. In the proposed framework, web services are ranked using their reputation as a result of provided feedback reflecting consumers’ satisfaction. However, selfish web services may alter their public reputation level by managing to get fake feedback. We investigate the payoffs of different scenarios by focusing on the issues that discourage web services to act maliciously. We also analyze the details of the proposed mechanism by discussing simulation and empirical results that fully depict the system parameters and show the feasibility of the proposed approach.     

一种矿用智能精确人员定位系统设计

针对现有煤矿井下精确人员定位系统采用大量有线通信线缆导致部署困难、成本高及紧急情况求援时智能化程度低等问题,设计了一种矿用智能精确人员定位系统。该系统中读卡器采用基于超宽带定位技术的到达时间测距方法准确获取人员标签位置,数据集中器通过LoRa无线通信技术收集读卡器采集的人员标签信息并上传至分站,地面监控中心根据分站上传的数据,在井下人员失去手动触发求救按钮能力时,通过紧急状况处理方案自动报警并通知管理人员。实测结果表明,该系统定位精度为1m,可在2km以内实现误码率小于5%的无线数据可靠传输,在井下人员失去手动触发求救按钮能力时自动报警率达93.5%以上。     

Fuzzy computational models for trust and reputation systems

In the recent past, a considerable research has been devoted to trust and reputation mechanisms to simplify complex transactions for open environments in social networking, e-commerce, and recommender systems (RS). In real life, we come to know about others through our social circle according to their reputation which is a public view. However, it is not always adequate to depend solely on the public view and therefore a trust measure is required to give a personalized view of the future encounters with a specific partner. In this paper, we propose fuzzy computational models for both trust and reputation concepts. Reciprocity and experience are used for trust modeling while the proposed reputation model is a fuzzy extension of beta reputation model. A two-level filtering methodology is proposed to benefit to a large extent from both the concepts separately. In order to justify the proposed models, we compared them with the existing reputation models for movie RS. The experimental results show that the incorporation of trust and reputation concepts into RS indeed improves the recommendation accuracy and establish that our models are better than beta and the popular eBay reputation models.     

The impact of reputation on supply chains. An analysis of permanent and discounted reputation

In long-term recurring contractual relationships, which are common in the B2B-arena, reputation and trust play a crucial role. This analysis investigates the joint impact of reputation and price-based ranking of suppliers on the material flow in the supply chain. Positive reputation proves to be a key factor in reaching dominating market positions, which illustrates the importance of building brand awareness in all stages of a supply chain. Through our simulation, it will be observed that the ranking of suppliers by reputation-based choice has a stabilizing effect on the material flow in the supply chain. A strong reputation component in the individual choice stimulates the formation of monopolies, while the discount of reputation imposes a countertendency on this effect. The Bullwhip Effect, another phenomenon that carries a countertendency to the reputation-based monopoly effect, is observed to be even stronger for members of tiers with a high fluctuation of order rates.     

A linear actuator with an SMA clamping mechanism for dual-slider positioning

Microsystem Technologies - In this paper, a linear actuator with a shape memory alloy (SMA) clamping mechanism for dual-slider positioning is proposed by using a single piezoelectric element (PZT)....     

New acoustic positioning system for an underwater robot using multiple frequencies

Nowadays, robots are used for many types of underwater work, and knowing their position accurately is very important. Conventional positioning systems are based on the time difference or phase lag of sound waves. However, such systems are complex and expensive, and real-time positioning is difficult and not very accurate. We propose a new system using the loss of sound propagation and a sensor network. In a previous study, we separated directly arrived waves from received waves and measured their amplitude or power. Using this data, we calculated the distance. However, the signal included many types of reflected wave, and we were not able to obtain a correct value over long distances where the direct waves cannot be separated from the influence of the reflected waves. In this study, we propose a new method based on sounds at multiple frequencies. This method uses sounds of several different frequencies, and sends them sequentially at constant intervals. The distance can be calculated by taking the average power of the signals received. The advantage of this method is that it is not necessary to use any separating process, and longer distances can be measured.     

Study and implementation of an EKF GIB-based underwater positioning system

The paper addresses the problem of estimating the position of an underwater target in real time. In the scenario adopted, the target carries a pinger that emits acoustic signals periodically, as determined by a very high precision clock that is synchronized with GPS, prior to system deployment. The target is tracked from the surface by using a system of four buoys equipped with hydrophones and electronic circuitry that measures the times of arrival of the acoustic signals emitted by the pinger or, equivalently, the four target-to-buoy range measurements (a commercial version of this setup is the GIB system). Due to the finite speed of propagation of sound in water, these measurements are obtained with different latencies. The paper tackles the problem of underwater target tracking in the framework of extended Kalman filtering by relying on a purely kinematic model of the target. The paper further shows also how the differently delayed measurements can be merged using a back and forward fusion approach. A measurement validation procedure is introduced to deal with dropouts and outliers. Simulation as well as experimental results illustrate the performance of the filter proposed.     

Evaluation and design of online cooperative feedback mechanisms for reputation management

This research evaluates and analyzes existing mechanisms of online reputation systems based on cooperative feedbacks of past transaction information. We find existing popular feedback systems do not provide sustained incentives for sellers to behave honestly over time. We propose a new design of reputation system based on exponential smoothing. This mechanism is shown to be more robust compared to the existing systems. We relax the assumption of a static product value and have implemented a two-level exponential smoothing policy to process and aggregate reputation information. The simulation results show that the policy can serve as a sustained incentive mechanism for the seller.     

An integrated trust and reputation model for open multi-agent systems

Trust and reputation are central to effective interactions in open multi-agent systems (MAS) in which agents, that are owned by a variety of stakeholders, continuously enter and leave the system. This openness means existing trust and reputation models cannot readily be used since their performance suffers when there are various (unforseen) changes in the environment. To this end, this paper presents FIRE, a trust and reputation model that integrates a number of information sources to produce a comprehensive assessment of an agent’s likely performance in open systems. Specifically, FIRE incorporates interaction trust, role-based trust, witness reputation, and certified reputation to provide trust metrics in most circumstances. FIRE is empirically evaluated and is shown to help agents gain better utility (by effectively selecting appropriate interaction partners) than our benchmarks in a variety of agent populations. It is also shown that FIRE is able to effectively respond to changes that occur in an agent’s environment.     

Measurement and storage of a network of jacobians as a method for the visual positioning of a robot arm

The goal of this paper is to describe a method to position a robot arm at any visible point of a given workspace without an explicit on line use of the analytical form of the transformations between real space and camera coordinates (camera calibration) or between cartesian and joint coordinates (direct or inverse kinematics of the robot arm). The formulation uses a discrete network of points distributed all over the workspace in which a procedure is given to measure certain Jacobian matrices which represent a good local linear approximation to the unknown compound transformation between camera and joint coordinates. This approach is inspired by the biological observation of the vestibulo-ocular reflex in humans (VOR). We show that little space is needed to store the transformation at a given scale, as feedback on the visual coordinates is used to improve precision up to the limit of the visual system. This characteristic also allows the plant to cope with disturbances in camera positioning or robot parameters. Furthermore, if the dimension of the visual space is equal or bigger than the motor space dimension, the transformation can be inverted, resulting in a realistic model of the plant able to be used to train other methods for the determination of visuo-motor mapping. As a test of the method an experiment to position a real robot arm is presented, together with another experiment showing the robot executing a simple task (building a tower of blocks).     

Security threats scenarios in trust and reputation models for distributed systems

Trust and reputation management over distributed systems has been proposed in the last few years as a novel and accurate way of dealing with some security deficiencies which are inherent to those environments. Thus, many models and theories have been developed in order to effective and accurately manage trust and reputation in those communities. Nevertheless, very few of them take into consideration all the possible security threats that can compromise the system. In this paper, we present some of the most important and critical security threats that could be applied in a trust and reputation scheme. We will describe and analyze each of those threats and propose some recommendations to face them when developing a new trust and reputation mechanism. We will also study how some trust and reputation models solve them. This work expects to be a reference guide when designing secure trust and reputation models.     

Formalization of ensuring the information security of an organization

In this paper, we propose an algorithm for solving the problem of ensuring the information security of an organization. The algorithm consists of generating a set of threats aimed at the resources of an organization, generating variants of measures intended to provide protection from these threats, and formulating problems of optimizing the selection of measures intended to ensure information security. The algorithm is used in an expert, automatized information system for decision-making support.     

OFDM中程水声通信系统仿真及实验

正交频分复用（OFDM）技术具有抗多释、频带利用充分、传输数据率高的优点,存水声通信中具有重要的发展前景。但是目前的相关研究多集中在几百米到几千米的近程水声通信,随着传输距离的增加,信道条件恶劣,多径、多普勒频移影响加剧,需要设计相应的OFDM系统并采取有效手段改善系统性能。该文综合分析了10公里距离水声通信的影响因素,设计出相应OFDM系统和合理系统参数,仿真了系统对信道、多普勒影响的校正,并给出湖试结果。分析表明该系统性能可靠,传输数据率高。     

Semantic Technology for Capturing Communication Inside an Organization

Using semantic technologies in various domains, researchers have developed domain-specific ontologies to capture knowledge and enable reasoning. Organizations can support such knowledge management by capturing knowledge of their own people and their communication records, including email exchanges. The proposed approach analyzes an internal social network and uses the resulting information to produce an informal organizational structure. The authors evaluated their approach using a mid-size organization's actual data and compared the informal structure they obtained with the formal organizational structure. As the results show, the approach proved useful for modeling social structures based on real-world communication records.     

Algorithm for calibration of the electromagnetic positioning system

Consideration was given to the problem of relative positioning with the use of variable magnetic field. Preliminary calibration of the positioning system was shown to be necessary to increase precision in determination of the navigation parameters. Various approaches to the calibration experiment were discussed. Efficient calibration algorithms were proposed, and a numerical example of solving a calibration problem was presented.