Content Scheduling in Multimedia Interactive Mobile Games

In this paper, we study how to implement interactive multimedia services using a DVB-H broadcast channel combined with a point-to-point channel, such as 3G or GPRS. We study the problem in the context of a location-based interactive mobile game. The technical challenge is to schedule the sending of data over the broadcast channel while maintaining Quality-of-Service, that is, sending the right data to the right user at the right time to provide a seamless interactive experience. We explore design issues and problems related to the scheduling of content in the game, present a usecase study to describe scheduling problems and propose a content scheduling algorithm to solve these problems. Moreover, we provide a simulation of the system and the experimental results to show how different game parameters influence the in-time delivery of the multimedia content to the players. We conclude that most of the problems involved with our approach can be expressed as the problem of defining delivery deadlines for a scheduling algorithm

Nano-EngineeredThermoelectric Materials for Waste Heat Recovery

Energy crisis and thermal management related issues have been highlighted in the modern century due to escalating demands for energy consumption and global warming from fossil fuels. Sustainable and alternative energy sources are an ever growing global concern. Thermoelectric (TE) materials have gained significant interest, due to effective solid-state energy conversion from waste heat to useful electrical energy and vice versa.   Clean, noise-free, and environment-friendly operation of TE devices has triggered great attention in viable technologies including automotive, military equipment, aerospace, and industries to scavenge waste heat into power. To date, conventional TE materials have shown limited energy conversion efficiency, i.e. TE Figure of Merit (ZT). However, the concept of nanostructuring and development of novel TE materials have opened excellent avenues to improve significantly the ZT values. Nano-engineered bulk TE materials allow effective phonon scattering at the high density of grain boundaries, which offer a way of lowering the thermal conductivity.  Large-scale synthesis of TE nanomaterials is a challenge for the TE industry because of expensive fabrication processes involved. This thesis reports several nano-engineering approaches for fabricating large quantities of bulk nanostructured TE materials. We have developed bottom-up chemical synthesis routes, as well as top-down mechanical alloying methodologies, to produce highly pure, homogenous and highly crystalline TE nanomaterials. State of the art chalcogenide, iron antimonide, and silicide based TE materials have been investigated in this thesis. Chalcogenide are the best candidates for TE devices operating at temperature range up to 450 K.  Iron antimonide (FeSb2) have shown attractive performance below room temperature. Earth abundant and environment friendly, silicide based materials have better ZT performance in the range of 600-900 K.  Spark plasma sintering (SPS) was utilized to preserve the nanostructuring and to achieve the highest compaction density. Comprehensive physiochemical characterizations were performed on as-prepared and SPS compacted samples. Detailed TE evaluation of the fabricated materials showed significant improvement in ZT for all categories of TE materials.QC 20140918</p

Towards combining interactive mobile TV and smart spaces : architectures, tools and application development

Technological developments in microprocessors and ICT landscape have made a shift to a new era where computing power is embedded in numerous small distributed objects and devices in our everyday lives. These small computing devices are ne-tuned to perform a particular task and are increasingly reaching our society at every level. For example, home appliances such as programmable washing machines, microwave ovens etc., employ several sensors to improve performance and convenience. Similarly, cars have on-board computers that use information from many di erent sensors to control things such as fuel injectors, spark plug etc., to perform their tasks e ciently. These individual devices make life easy by helping in taking decisions and removing the burden from their users. All these objects and devices obtain some piece of information about the physical environment. Each of these devices is an island with no proper connectivity and information sharing between each other. Sharing of information between these heterogeneous devices could enable a whole new universe of innovative and intelligent applications. The information sharing between the devices is a diffcult task due to the heterogeneity and interoperability of devices. Smart Space vision is to overcome these issues of heterogeneity and interoperability so that the devices can understand each other and utilize services of each other by information sharing. This enables innovative local mashup applications based on shared data between heterogeneous devices. Smart homes are one such example of Smart Spaces which facilitate to bring the health care system to the patient, by intelligent interconnection of resources and their collective behavior, as opposed to bringing the patient into the health system. In addition, the use of mobile handheld devices has risen at a tremendous rate during the last few years and they have become an essential part of everyday life. Mobile phones o er a wide range of different services to their users including text and multimedia messages, Internet, audio, video, email applications and most recently TV services. The interactive TV provides a variety of applications for the viewers. The combination of interactive TV and the Smart Spaces could give innovative applications that are personalized, context-aware, ubiquitous and intelligent by enabling heterogeneous systems to collaborate each other by sharing information between them. There are many challenges in designing the frameworks and application development tools for rapid and easy development of these applications. The research work presented in this thesis addresses these issues. The original publications presented in the second part of this thesis propose architectures and methodologies for interactive and context-aware applications, and tools for the development of these applications. We demonstrated the suitability of our ontology-driven application development tools and rule basedapproach for the development of dynamic, context-aware ubiquitous iTV applications

Usability Evaluation of Food Wastage Mobile Application: A Case of Pakistan

The continuous rise in food scarcity is creating an alarming situation in underdeveloped countries and Pakistan is no exception. According to the Global Hunger Report published in 2020, Pakistan was ranked 88th among 107 countries, with 28.5% of the population under-nourished. To address the situation, food resources need to be more effectively utilized. To reduce food wastage, various efforts have been made to identify the issues associated with the lack of adoption of food wastage mobile application(s). Using purposeful sampling and data from 150 respondents collected from a public sector university and a software house, participants’ experience in using selected food wastage mobile applications were evaluated. In terms of usability parameters, the study proposes improvements in the prototype design

Temperature dependent structure stability studies on thermoelectric Yb0.025Fe0.3Co0.7Sb3

Depending on their application temperature thermoelectric (TE) materials are classified in three main categories; as low (up to 250°C), intermediate (up to 550°C) and high (above 600°C) temperature. Currently, Skutterudites (CoSb3) based materials have shown promising results in the intermediate temperature range (300-500°C). This family of material is highly suitable for automotive, marine transportation and industrial power generation applications to recover the waste heat from the exhaust and generate electricity. Conventional TE modules need p- and n-type semiconductor materials and for the skutterudite family, iron (Fe) has proven to be among the best candidates for the substitution of cobalt sites. Additionally, rare earths are introduced as rattlers in the crystal cages of the skutterudite to decrease the thermal conductivity, thus improving the figure of merit ZT of the TE material. For practical application for device fabrication, stability of these materials is of great importance. Compositional stability is being addressed as the material decomposes above certain temperature. Temperature dependent x-ray diffraction study was performed on Fe substituted, Yb-filled skutterudites, using Beam Line I711 at MAX LAB, to observe the crystal structure as a function of temperature. Diffraction patterns were collected from room temperature up to 500°C by utilizing Huber furnace. The results show success in filling process showing almost 80% reduction of the thermal conductivity from bulk. Additionally the thermal expansion coefficient value was within the average value for skutterudites which proves practical application of this powder for industrial applications

Fabrication and characterization of nanostructured thermoelectric FexCo1-xSb3

A novel synthesis route for the fabrication of p-type nanostructured skutterudite, FexCo1-xSb3 in large quantity is reported. This scalable synthesis route provides nano-engineered material with less impact on the environment compared to conventional synthesis procedures. Several Fe substituted compositions have been synthesized to confirm the feasibility of the process. The process consists of a nano-sized precursor fabrication of iron and cobalt oxalate, and antimony oxides by chemical co-precipitation. Further thermochemical processes result in the formation of iron substituted skutterudites. The nanopowders are compacted by Spark Plasma Sintering (SPS) technique in order to maintain nanostructure. Detailed physicochemical as well as thermoelectric transport properties are evaluated. Results reveal strongly reduced thermal conductivity values compared to conventionally prepared counterparts, due to nanostructuring. P-type characteristic was observed from the Seebeck measurements while electrical conductivity is high and shows metallic behavior. The highest TE figure of merit of 0.25 at 800 K has been achieved, which is strongly enhanced with respect to the mother compound CoSb3. This suggests the promise of the utilized method of fabrication and processing for TE applications with improved performance.QC 20150312</p