SecMR – a secure multipath routing protocol for ad hoc networks

Multipath routing in ad hoc networks increases the resiliency against security attacks of collaborating malicious nodes, by maximizing the number of nodes that an adversary must compromise in order to take control of the communication. In this paper, we identify several attacks that render multipath routing protocols vulnerable to collaborating malicious nodes. We propose an on-demand multipath routing protocol, the secure multipath routing protocol (SecMR), and we analyze its security properties. Finally, through simulations, we evaluate the performance of the SecMR protocol in comparison with existing secure multipath routing protocols.     

Intelligent search in social communities of smartphone users

Social communities of smartphone users have recently gained significant interest due to their wide social penetration. The applications in this domain, however, currently rely on centralized or cloud-like architectures for data sharing and searching tasks, introducing both data-disclosure and performance concerns. In this paper, we present a distributed search architecture for intelligent search of objects in a mobile social community. Our framework, coined SmartOpt, is founded on an in-situ data storage model, where captured objects remain local on smartphones and searches then take place over an intelligent multi-objective lookup structure we compute dynamically. Our MO-QRT structure optimizes several conflicting objectives, using a multi-objective evolutionary algorithm that calculates a diverse set of high quality non-dominated solutions in a single run. Then a decision-making subsystem is utilized to tune the retrieval preferences of the query user. We assess our ideas both using trace-driven experiments with mobility and social patterns derived by Microsoft’s GeoLife project, DBLP and Pics ‘n’ Trails but also using our real Android SmartP2P (http://smartp2p.cs.ucy.ac.cy/) system deployed over our SmartLab (http://smartlab.cs.ucy.ac.cy/) testbed of 40+ smartphones. Our study reveals that SmartOpt yields high query recall rates of 95 %, with one order of magnitude less time and two orders of magnitude less energy than its competitors.     

Scalable Distributed Sensor Fault Diagnosis for Smart Buildings

The enormous energy use of the building sector and the requirements for indoor living quality that aim to improve occupants’ productivity and health, prioritize Smart Buildings as an emerging technology. The Heating, Ventilation and Air-Conditioning (HVAC) system is considered one of the most critical and essential parts in buildings since it consumes the largest amount of energy and is responsible for humans comfort. Due to the intermittent operation of HVAC systems, faults are more likely to occur, possibly increasing eventually building’s energy consumption and/or downgrading indoor living quality. The complexity and large scale nature of HVAC systems complicate the diagnosis of faults in a centralized framework. This paper presents a distributed intelligent fault diagnosis algorithm for detecting and isolating multiple sensor faults in large-scale HVAC systems. Modeling the HVAC system as a network of interconnected subsystems allows the design of a set of distributed sensor fault diagnosis agents capable of isolating multiple sensor faults by applying a combinatorial decision logic and diagnostic reasoning. The performance of the proposed method is investigated with respect to robustness, fault detectability and scalability. Simulations are used to illustrate the effectiveness of the proposed method in the presence of multiple sensor faults applied to a 83-zone HVAC system and to evaluate the sensitivity of the method with respect to sensor noise variance.      

A novel finite element formulation for frictionless contact problems

This article advocates a new methodology for the finite element solution of contact problems involving bodies that may undergo finite motions and deformations. The analysis is based on a decomposition of the two-body contact problem into two simultaneous sub-problems, and results naturally in geometrically unbiased discretization of the contacting surfaces. A proposed two-dimensional contact element is specifically designed to unconditionally allow for exact transmission of constant normal traction through interacting surfaces.     

长江葛洲坝下游鱼类资源量的关键水文指标识别

采用遗传规划法和相关系数法识别影响鱼类资源量的关键水文指标,结果显示坝下经济鱼类天然捕捞产量与年最大流量、高流量脉冲历时、10月和12月的月均流量正相关;四大家鱼鱼苗丰度与涨水率、7日最大流量、5月和6月的月均流量正相关;中华鲟繁殖群体数量与基流指数和涨水率呈正相关,与年最小流量、日均流量逆转次数负相关。这些水文指标分别反映了流量的量值、变化率和历时等特征对鱼类的影响。建立了关键水文指标与鱼类资源量之间的非线性函数关系式,通过对比计算值与实测值发现遗传规划法的拟合效果明显优于相关系数法,表明遗传规划法更适用于识别影响鱼类资源量的关键水文指标。     

A Heuristic Evaluation for Deaf Web User Experience (HE4DWUX)

Websites that are usable and accessible can have a positive impact on the overall user experience. Usability Inspection Methods (UIMs) can be applied to evaluate and measure the usability. The current research in the fields of Web Accessibility and Human –Computer Interaction (HCI) is in need of additional UIMs that can be applied to also measure the accessibility, in addition to the usability alone. In this article, a novel UIM in the form of a heuristic evaluation is presented. The heuristic evaluation aims to support HCI experts and Web developers in designing and evaluating websites that provide positive user experiences to users who are deaf. This article discusses the development of the Heuristic Evaluation for Deaf Web User Experience (HE4DWUX). Following an iteration cycle, version 2 of the HE4DWUX is presented in Appendix A. An existing three-phase process to develop heuristics for specific application domains was applied to construct the HE4DWUX. The outcome of this research is 12 heuristics, with each containing its own set of checklist items to operationalize its applicability in measuring the Web user experience for users who are deaf. The heuristics and their checklist items can identify important aspects of design that will impact the Web user experience for this particular user group.     

Arsonoliposomes: novel nanosized arsenic-containing vesicles for drug delivery

Natural and synthetic arsenolipids, have been discovered, synthesized, and evaluated for their biological activity. Arsonolipids, are analogs of phosphonolipids, in which P has been replaced by As. The synthesis of arsonolipids has been explored and a simple one-pot method with high yield is currently available for their preparation. However, although arsonolipids posses interesting biophysical and biochemical properties their anticancer or antiparasitic activity is not considered adequate for therapeutic applications. But when arsonolipids are incorporated in liposomes, the vesicles formulated have interesting possibilities, as seen in a number of studies. In cell culture studies, nanosized arsonolipid-containing liposomes or else arsonoliposomes, showed increased toxicity against cancer cells (compared to that of arsenic trioxide) but at the same time were less toxic than arsenic trioxide for normal cells. Furthermore, arsonoliposomes also demonstrate antiparasitic activity in vitro. Nevertheless, As is rapidly cleared from blood after in vivo administration of arsonoliposomes, and this will highly limit possible therapeutic applications. In addition, the fact that arsonoliposomes were observed to aggregate and subsequently fuse into larger particles in presence of cations, may also be considered as a problem. Thereby, methods to modulate the stability of arsonoliposomes and, perhaps, their in vivo distribution (as surface property modification) are currently being investigated. In very recent experiments it has been shown that arsonoliposome pegylation results in the formation of liposomes with very high membrane integrity. In addition, pegylation results in increased physical stability of arsonoliposomes and abolishment of cation-induced aggregation and fusion. Nevertheless, further in vivo studies are required in order to prove if pegylation alters arsonoliposome in vivo kinetics in a positive way, without affecting their activity. From studies performed thus far it is concluded that arsonoliposomes are nanosized-vesicles with interesting properties that justify further exploitation towards the development of therapeutic systems for cancer or parasitic diseases.