Yet another insecure group key distribution scheme using secret sharing

A recently proposed group key distribution scheme known as UMKESS, based on secret sharing, is shown to be insecure. Not only is it insecure, but it does not always work, and the rationale for its design is unsound. UMKESS is the latest in a long line of flawed group key distribution schemes based on secret sharing techniques.Comment: Minor modifications to provide extra backgroun

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

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

Adaptive-Compression Based Congestion Control Technique for Wireless Sensor Networks

Congestion in a wireless sensor network causes an increase in the amount of data loss and delays in data transmission. In this paper, we propose a new congestion control technique (ACT, Adaptive Compression-based congestion control Technique) based on an adaptive compression scheme for packet reduction in case of congestion. The compression techniques used in the ACT are Discrete Wavelet Transform (DWT), Adaptive Differential Pulse Code Modulation (ADPCM), and Run-Length Coding (RLC). The ACT first transforms the data from the time domain to the frequency domain, reduces the range of data by using ADPCM, and then reduces the number of packets with the help of RLC before transferring the data to the source node. It introduces the DWT for priority-based congestion control because the DWT classifies the data into four groups with different frequencies. The ACT assigns priorities to these data groups in an inverse proportion to the respective frequencies of the data groups and defines the quantization step size of ADPCM in an inverse proportion to the priorities. RLC generates a smaller number of packets for a data group with a low priority. In the relaying node, the ACT reduces the amount of packets by increasing the quantization step size of ADPCM in case of congestion. Moreover, in order to facilitate the back pressure, the queue is controlled adaptively according to the congestion state. We experimentally demonstrate that the ACT increases the network efficiency and guarantees fairness to sensor nodes, as compared with the existing methods. Moreover, it exhibits a very high ratio of the available data in the sink

UML consistency rules: a systematic mapping study

Context: The Unified Modeling Language (UML), with its 14 different diagram types, is the de-facto standard tool for objectoriented modeling and documentation. Since the various UML diagrams describe different aspects of one, and only one, software under development, they are not independent but strongly depend on each other in many ways. In other words, the UML diagrams describing a software must be consistent. Inconsistencies between these diagrams may be a source of the considerable increase of faults in software systems. It is therefore paramount that these inconsistencies be detected, ana

Application of computer vision techniques for laser-based global localization of a mobile robot in a known, static environment

El problema de la localización global, es decir, la localización de un robot en un entorno conocido sin información sobre sus estados previos, ha sido ampliamente estudiado mediante diferentes métodos en la literatura. Un gran número de algoritmos han sido presentados y probados considerando varias condiciones. El objetivo de este trabajo es comparar diferentes métodos de representación de ocupación de celdillas construidos a partir de datos provistos por un láser utilizando técnicas de visión por computador. El enfoque seguido usa comparación visual de un mapa global con uno local, creado gracias al sensor láser. Esta elección permite una fácil integración con sistemas robóticos existentes al mismo tiempo que evita problemas típicos de soluciones puramente visuales, como la influencia de cambios de iluminación. Los dos algoritmos comparados—basados en área y en puntos característicos, respectivamente—han sido evaluados en un entorno interior simulado. Se ha asumido una situación estática, sin presencia de obstáculos móviles. El trabajo ha sido realizado durante un programa de movilidad en el extranjero, por lo que el documento se adapta en fondo y forma a las especificaciones de la Universidad de destino

The determinants of bank branch location in India: An empirical investigation

YesBank branching plays a significant role in a wide range of economic activities. Existing studies on determinants of bank branching activities largely focus on developed countries, studies devoted to developing countries are scant. We present the first study that examines the determinants of bank branching activities in one of the largest developing country India. We employ a unique longitudinal data to study the determinants of bank branch location in India. This data is collected at the state level covering 25 Indian states for the period 2006 to 2017. We employ Poisson regression that are better suited for modelling counted dependent variable. First, region and bank specific factors such as size of population and bank deposits influence location of bank branches. Second, the relationship between these factors and branch locations is heterogeneous across different types of banks and across states with different business environments. First, from the view of banks, considering the factors of branch location are crucial in order to set out branching strategy. Irrespective of policy measures aimed at promoting financial inclusion in India, we show that banks consider economic activities in the region in locating their branches. Second, from the view of policy makers and regulators, such branching strategy could potentially contribute to financial exclusion. As a result, population in the less developed regions may be excluded from accessing financial services. Hence, policy makers and regulators should take into this account when formulating policies aimed at promoting financial inclusion. First, while existing studies largely focus on developed countries, studies devoted to developing countries are scant. To the best of our knowledge, we have not come across any study that investigates the determinants of bank branch location in India, so we reasonably believe that ours is a first-of-its-kind. Second, our study provides a new perspective concerning how regional and bank specific factors influence banks of different ownership in locating branches. Third, while traditional regression used to be a method of choice among early studies, we employ Poisson regression that are better suited for modelling counted dependent variable

A systematic identification of consistency rules for UML diagrams

UML diagrams describe different views of one piece of software. These diagrams strongly depend on each other and must therefore be consistent with one another, since inconsistencies between diagrams may be a source of faults during software development activities that rely on these diagrams. It is therefore paramount that consistency rules be defined and that inconsistencies be detected, analyzed and fixed. The relevant literature shows that authors typically define their own UML consistency rules, sometimes defining the same rules and sometimes defining rules that are already in the UML standard. The reason might be that no consolidated set of rules that are deemed relevant by authors can be found to date. The aim of our research is to provide a consolidated set of UML consistency rules and obtain a detailed overview of the current research in this area. We therefore followed a systematic procedure in order to collect and analyze UML consistency rules. We then consolidated a set of 116 UML consistency rules (avoiding redundant definitions or definitions already in the UML standard) that can be used as an important r