A Simplified Method for Performance Evaluation of Public Transit Under Reneging Behavior of Passengers

This paper develops a model based on the Markov Chain technique to evaluate performance of a public transport route. The model addresses a special situation where a passenger left behind by a bus leaves the system without any further waiting to make an alternative travel arrangement. Such reneging behavior is indicative of an infinite penalty associated with further waiting from a passenger viewpoint. Apart from the theoretical derivations for the various attributes of interest, numerical examples to analyze the system performance (such as expected number of passengers served, expected number of abandoned passengers, and expected amount of unused space on the transit system) are presented. This provides insights for optimum selection of fleet size and size of vehicle

Proposed Thermal Circuit Model for the Cost Effective Design of Fin FET

The Complementary metal-oxide-semiconductor (CMOS) device has been rapidly evolving and its size has been drastically decreasing ever since it was first fabricated in 1960 [Us Patent 3,356,858: 1967]. The substantial reduction in the CMOS device size has led to short channel effects which have resulted in the introduction of Fin Field Effect Transistor (FinFET), a tri-gate transistor built on a silicon on insulator (SOI) substrate. Furthermore, due to the geometry of the FinFET the severity of the heating problem has dramatically increased. Self-heating in the 3-dimensional FinFET device enhances the temperature gradients and peak temperature, which decrease drive current, increase the interconnect delays and degrade the device and interconnect reliability. In this work we have proposed a methodology to develop an accurate thermal model for the FinFET through a rigorous physics-based mathematical approach. A thermal circuit for the FinFET will be derived from the model. This model will allow chip designers to predict interconnect temperature which will lead them to achieve cost-effective design for the FinFET-based semiconductor chips. Keywords: Bulk CMOS, SOI CMOS, FinFET, Thermal heating

TUKAB: An Efficient NAT Traversal Scheme on Security of VoIP Network System Based on Session Initiation Protocol

Voice over Internet Protocol (VoIP) is subject to many security threats unique to both telephony and traditional Internet data transmission. As adoption of Session Initiation Protocol (SIP) based telephony increases, concerns are rising over risks to system confidentiality, integrity and availability. Currently, several VoIP security tools are available to detect vulnerabilities and protect against attacks. In this paper we present various issues concerning the security of VoIP. A brief discussion of the SIP protocol is presented based on its operating principle. Finally we proposed a solution for the Network Address Translation (NAT) traversal problem of SIP based networks. This solution supports all types of NAT and maintains the current VoIP architecture. Based on our experiment, we examined the latency, buffer size and voice packet loss under various network conditions. We found that it is possible to establish a call from outside the NAT to inside maintaining the quality issues of VoIP call. With this approach it is possible to use the current network architecture with having few changes in the registrar server. Hence we evaluate our model showing the QoS conditions that achieves both high efficiency and secure voice transmission. Sufficient simulation results are presented to verify our model

Spatial distribution of heatwave vulnerability in a coastal city of Bangladesh

While extreme heat events received wider attention in recent years, understanding heatwave vulnerability is still a challenging task that requires a clear understanding of a range of location-dependent climatic, socio-economic, physiological, and environmental parameters. This study investigates the spatial distribution of heatwave vulnerability in Chattogram City Corporation (CCC) — the commercial capital of Bangladesh. A heatwave vulnerability index (HVI) was developed, including various parameters related to three latent variables — exposure, sensitivity, and adaptive capacity — derived using remote sensing and socio-economic data. Factor analysis was performed to assess all parameters related to HVI. Besides, spatial autocorrelation, cluster and outlier analyses, and hot spot analysis were carried out to investigate the spatial distribution of HVI. This study shows a spatial distribution of HVI in CCC, which is spatially associated with various individual parameters. A total of seven wards (smallest administrative zone of CCC) were found to be very highly vulnerable to the heatwave. This study further reveals that heatwave vulnerability is randomly distributed throughout the city, although the high land surface temperature is concentrated in the existing built-up areas. It also identified three major hot spots of heatwave vulnerability in CCC. The methodology and findings of this study will be of interest to the policymakers and city planners to prepare mitigation plans, policies, and strategies to mitigate this hazard

Review of electric vehicle energy storage and management system: Standards, issues, and challenges

Renewable energy is in high demand for a balanced ecosystem. There are different types of energy storage systems available for long-term energy storage, lithium-ion battery is one of the most powerful and being a popular choice of storage. This review paper discusses various aspects of lithium-ion batteries based on a review of 420 published research papers at the initial stage through 101 published research articles that have been finally reviewed. This review paper focuses on several topics, including electrical vehicle (EV) systems, energy management systems, challenges and issues, and the conclusions and recommendations for future work. EV systems discuss all components that are included in producing the lithium-ion battery. The energy storage section contains the batteries, super capacitors, fuel cells, hybrid storage, power, temperature, and heat management. Energy management systems consider battery monitoring for current and voltage, battery charge-discharge control, estimation and protection, cell equalization. This paper's challenges and issues discuss some of the critical aspects of lithium-ion batteries, including temperature and safety, life-cycle and memory effects, environmental effects, and recycling processes. The conclusion and recommendation of this paper indicate the future scope of research. This review paper can provide the lithium-ion battery's insight, overall synopsis and contribution, and further research directions to the EV system

A Planar Antenna On Flexible Substrate For Future 5G Energy Harvesting In Malaysia

This article presents a planar monopole antenna on flexible substrate for middle band 5G (3.5 GHz) application in Malaysia. The antenna has been designed and optimized for its gain and efficiency with an improved performance in contrast of flexible substrate-based other antennas. The antenna resonates at 3.53 GHz and it has a -10dB bandwidth of 545 MHz. The bending effects of this antenna on the S-parameter and gain have also been investigated. The antenna is able to suppress all the other frequency bands until 20 GHz. The designed antenna has been utilized with a newly designed rectifier to act as an rectenna at 3.5 GHz for RF energy harvesting applications. A reasonable amount of DC output voltage of 930 mV, and a Power Conversion Efficiency of 43.5% have been obtained while 0 dBm RF input power is delivered to the rectifier input terminal. Apart from the utilization as an energy harvester being connected with the proposed rectifier, the designed antenna on flexible substrate can also be employed to biomedical and sensor applications

A tree-profile shape ultra wide band antenna for chipless RFID tags

In this article, a new small size planar microstrip tree profile shaped Ultra-Wide Band (UWB) antenna with partial ground plane has been presented. The antenna is designed for chipless RFID tags that are working in UWB region. The operating frequency of the antenna is between 2.72 GHz to 11.1 GHz which covers the entire UWB frequency band. The antenna exhibits comparatively high realized gain of 4.2 dBi with respect to its small size of 27 × 40 mm2 and have a gain to aperture ratio of 0.243 which is comparatively higher than other existing retransmission-based chipless RFID antennas. Another aspect of this antenna is its total efficiency which never goes below 80% throughout the entire bandwidth whereby it reaches as high as 96% at 3.5GHz. This design will motivate the chipless RFID designers to produce small size and cost effective tags

Ethnic Variation in Inflammatory Profile in Tuberculosis

PMCID: PMC3701709This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Vitamin D accelerates resolution of inflammatory responses during tuberculosis treatment

Calcidiol, the major circulating metabolite of vitamin D, supports induction of pleiotropic antimicrobial responses in vitro. Vitamin D supplementation elevates circulating calcidiol concentrations, and thus has a potential role in the prevention and treatment of infection. The immunomodulatory effects of administering vitamin D to humans with an infectious disease have not previously been reported. To characterize these effects, we conducted a detailed longitudinal study of circulating and antigen-stimulated immune responses in ninety-five patients receiving antimicrobial therapy for pulmonary tuberculosis who were randomized to receive adjunctive high-dose vitamin D or placebo in a clinical trial, and who fulfilled criteria for per-protocol analysis. Vitamin D supplementation accelerated sputum smear conversion and enhanced treatment-induced resolution of lymphopaenia, monocytosis, hypercytokinaemia, and hyperchemokinaemia. Administration of vitamin D also suppressed antigen-stimulated proinflammatory cytokine responses, but attenuated the suppressive effect of antimicrobial therapy on antigen-stimulated secretion of IL-4, CC chemokine ligand 5, and IFN-α. We demonstrate a previously unappreciated role for vitamin D supplementation in accelerating resolution of inflammatory responses during tuberculosis treatment. Our findings suggest a potential role for adjunctive vitamin D supplementation in the treatment of pulmonary infections to accelerate resolution of inflammatory responses associated with increased risk of mortality

Social capital and health: Does egalitarianism matter? A literature review

The aim of the paper is to critically review the notion of social capital and review empirical literature on the association between social capital and health across countries. The methodology used for the review includes a systematic search on electronic databases for peer-reviewed published literature. We categorize studies according to level of analysis (single and multilevel) and examine whether studies reveal a significant health impact of individual and area level social capital. We compare the study conclusions according to the country's degrees of economic egalitarianism. Regardless of study design, our findings indicate that a positive association (fixed effect) exists between social capital and better health irrespective of countries degree of egalitarianism. However, we find that the between-area variance (random effect) in health tends to be lower in more egalitarian countries than in less egalitarian countries. Our tentative conclusion is that an association between social capital and health at the individual level is robust with respect to the degree of egalitarianism within a country. Area level or contextual social capital may be less salient in egalitarian countries in explaining health differences across places