Adaptive authentication and key agreement mechanism for future cellular systems

Since the radio medium can be accessed by anyone, authentication of users is a very important element of a mobile network. Nowadays, in GSM/GPRS a challenge response protocol is used to authenticate the user to the mobile network. Similarly, in third generation mobile systems [3] a challenge response protocol was chosen in such a way as to achieve maximum compatibility with the current GSM security architecture. Both authentication mechanisms use symmetric key cryptography because of the limited processing power of the mobile devices. However, recent research [6] has shown that asymmetric, or public, key cryptography can be enabled successfully in future mobile terminals. In this paper, we propose a new adaptive authentication and key agreement protocol (AAKA) for future mobile communication systems. The novelty of AAKA and its main advantage over other challenge response protocols is that can be adaptive to the mobile environment and use symmetric and/or public key cryptography for user and network authentication

Multi-Party Trust Computation in Decentralized Environments

In this paper, we describe a decentralized privacy-preserving protocol for securely casting trust ratings in distributed reputation systems. Our protocol allows n participants to cast their votes in a way that preserves the privacy of individual values against both internal and external attacks. The protocol is coupled with an extensive theoretical analysis in which we formally prove that our protocol is resistant to collusion against as many as n-1 corrupted nodes in the semi-honest model. The behavior of our protocol is tested in a real P2P network by measuring its communication delay and processing overhead. The experimental results uncover the advantages of our protocol over previous works in the area; without sacrificing security, our decentralized protocol is shown to be almost one order of magnitude faster than the previous best protocol for providing anonymous feedback

Protecting biometric templates with image watermarking techniques

Biometric templates are subject to modifications for identity fraud especially when they are stored in databases. In this paper, a new approach to protecting biometric templates with image watermarking techniques is proposed. The novelty of this approach is that we have combined lattice and block-wise image watermarking techniques to maintain image quality along with cryptographic techniques to embed fingerprint templates into facial images and vice-versa. Thus, protecting them from being modified

Vulnerabilities of Decentralized Additive Reputation Systems Regarding the Privacy of Individual Votes

In this paper, we focus on attacks and defense mechanisms in additive reputation systems. We start by surveying the most important protocols that aim to provide privacy between individual voters. Then, we categorize attacks against additive reputation systems considering both malicious querying nodes and malicious reporting nodes that collaborate in order to undermine the vote privacy of the remaining users. To the best of our knowledge this is the first work that provides a description of such malicious behavior against such systems. In light of this analysis we demonstrate the inefficiencies of existing protocols

Accessibility-based reranking in multimedia search engines

Traditional multimedia search engines retrieve results based mostly on the query submitted by the user, or using a log of previous searches to provide personalized results, while not considering the accessibility of the results for users with vision or other types of impairments. In this paper, a novel approach is presented which incorporates the accessibility of images for users with various vision impairments, such as color blindness, cataract and glaucoma, in order to rerank the results of an image search engine. The accessibility of individual images is measured through the use of vision simulation filters. Multi-objective optimization techniques utilizing the image accessibility scores are used to handle users with multiple vision impairments, while the impairment profile of a specific user is used to select one from the Pareto-optimal solutions. The proposed approach has been tested with two image datasets, using both simulated and real impaired users, and the results verify its applicability. Although the proposed method has been used for vision accessibility-based reranking, it can also be extended for other types of personalization context

Bone mineral density in vocational and professional ballet dancers

Summary: According to existing literature, bone health in ballet dancers is controversial. We have verified that, compared to controls, young female and male vocational ballet dancers have lower bone mineral density (BMD) at both impact and non-impact sites, whereas female professional ballet dancers have lower BMD only at non-impact sites. Introduction: The aims of this study were to (a) assess bone mineral density (BMD) in vocational (VBD) and professional (PBD) ballet dancers and (b) investigate its association with body mass (BM), fat mass (FM), lean mass (LM), maturation and menarche. Methods: The total of 152 VBD (13 ± 2.3 years; 112 girls, 40 boys) and 96 controls (14 ± 2.1 years; 56 girls, 40 boys) and 184 PBD (28 ± 8.5 years; 129 females, 55 males) and 160 controls (27 ± 9.5 years; 110 female, 50 males) were assessed at the lumbar spine (LS), femoral neck (FN), forearm and total body by dual-energy X-ray absorptiometry. Maturation and menarche were assessed via questionnaires. Results: VBD revealed lower unadjusted BMD at all anatomical sites compared to controls (p < 0.001); following adjustments for Tanner stage and gynaecological age, female VBD showed similar BMD values at impact sites. However, no factors were found to explain the lower adjusted BMD values in VBD (female and male) at the forearm (non-impact site), nor for the lower adjusted BMD values in male VBD at the FN. Compared to controls, female PBD showed higher unadjusted and adjusted BMD for potential associated factors at the FN (impact site) (p < 0.001) and lower adjusted at the forearm (p < 0.001). Male PBD did not reveal lower BMD than controls at any site. Conclusions: both females and males VBD have lower BMD at impact and non-impact sites compared to control, whereas this is only the case at non-impact site in female PBD. Maturation seems to explain the lower BMD at impact sites in female VBD

Moving away from the motor vehicle: the German and Hong Kong experience

Includes bibliographical references and index.Based on: Proceedings of Seminar held on 13th April, 1992 at the University of Hong Kong. Sponsored by: The Geothe- Institut of Hong Kong, the Centre of Urban Planning & Environmental Management, Green Power, Hong Kong.Erratum slip inserted.published_or_final_versionCh.6 From pedestrian zones to traffic calmed city centres Monheim, Rolf Monheim, Rolf 57Ch.10 Prospects and opportunities for light rail transit Runnacles, Tim V. Runnacles, Tim V. 119List of tables vList of figures ivCh.12 Conclusions Chau, Simon Chau, Simon Dimitriou, Harry T. Dimitriou, Harry T. 143Ch.11 Visions of a more motor vehicle dependent-free strategy Dimitriou, Harry T. Dimitriou, Harry T. 131Preface Wang, Gungwu Wang, Gungwu viCh.9 Prospects for city and suburban public transport Meakin, Richard T. Meakin, Richard T. 103Ch.8 Managing transport for environmental quality Barron, William F. Barron, William F. 91Ch.7 The urban transport policy agenda revisited Dimitriou, Harry T. Dimitriou, Harry T. 75Ch.5 Cooperative urban traffic management Monheim, Rolf Monheim, Rolf 45Ch.4 New developments in urban and suburban public transport Retzko, Hans G. Retzko, Hans G. 37Ch.3 New goals, methods and procedures in urban traffic and transport planning Retzko, Hans G. Retzko, Hans G. 27Ch.2 Problems of traffic growth and strategies for traffic calming: perceptions among citizens and opinion makers Monheim, Rolf Monheim, Rolf 7Ch.1 Introdution Chau, Simon Chau, Simon Dimitriou, Harry T. Dimitriou, Harry T. 1Index 165Notes on contributors 163Appdx.2 Participants of the seminar 159Appdx.1 Transcript of panel discussion on visions of motor vehicle free cities 147Pt.2 The Hong Kong experiencePt.1 The German experienceAcknowledgements Dimitriou, Harry T. Dimitriou, Harry T. ixForeword Uwe, Nitschke Uwe, Nitschke vii

Occurrence and Treatment of Bone Atrophic Non-Unions Investigated by an Integrative Approach

Recently developed atrophic non-union models are a good representation of the clinical situation in which many nonunions develop. Based on previous experimental studies with these atrophic non-union models, it was hypothesized that in order to obtain successful fracture healing, blood vessels, growth factors, and (proliferative) precursor cells all need to be present in the callus at the same time. This study uses a combined in vivo-in silico approach to investigate these different aspects (vasculature, growth factors, cell proliferation). The mathematical model, initially developed for the study of normal fracture healing, is able to capture essential aspects of the in vivo atrophic non-union model despite a number of deviations that are mainly due to simplifications in the in silico model. The mathematical model is subsequently used to test possible treatment strategies for atrophic non-unions (i.e. cell transplant at post-osteotomy, week 3). Preliminary in vivo experiments corroborate the numerical predictions. Finally, the mathematical model is applied to explain experimental observations and identify potentially crucial steps in the treatments and can thereby be used to optimize experimental and clinical studies in this area. This study demonstrates the potential of the combined in silico-in vivo approach and its clinical implications for the early treatment of patients with problematic fractures

Caffeine increases strength and power performance in resistance‐trained females during early follicular phase

The effects of 4 mg·kg‐1caffeine ingestion on strength and power were investigated for the first time, in resistance‐trained females during the early follicular phase utilizing a randomized, double‐blind, placebo‐controlled, crossover design. Fifteen females (29.8±4.0 years, 63.8±5.5 kg [mean±SD]) ingested caffeine or placebo 60 minutes before completing a test battery separated by 72 hours. One‐repetition maximum (1RM), repetitions to failure (RTF) at 60% of 1RM, were assessed in the squat and bench press. Maximal voluntary contraction torque (MVC) and rate of force development (RFD) were measured during isometric knee‐extensions, while utilizing interpolated twitch technique to measure voluntary muscle activation. Maximal power and jump height were assessed during countermovement jumps (CMJ). Caffeine metabolites were measured in plasma. Adverse effects were registered after each trial. Caffeine significantly improved squat (4.5±1.9%, effect size [ES]: 0.25) and bench press 1RM (3.3±1.4%, ES: 0.20), and squat (15.9±17.9%, ES: 0.31) and bench press RTF (9.8±13.6%, ES: 0.31), compared to placebo. MVC torque (4.6±7.3%, ES: 0.26), CMJ height (7.6±4.0%, ES: 0.50) and power (3.8±2.2%, ES: 0.24) were also significantly increased with caffeine. There were no differences in RFD or muscle activation. Plasma [caffeine] was significantly increased throughout the protocol and mild side‐effects of caffeine were experienced by only 3 participants. This study demonstrated that 4 mg·kg‐1 caffeine ingestion enhanced maximal strength, power and muscular endurance in resistance‐trained and caffeine‐habituated females during the early follicular phase, with few adverse effects. Female strength and power athletes may consider using this dose pre‐competition and ‐training as an effective ergogenic aid