Mobile Computing Applications Research Articles

High-Performance Nanowire Electronics and Photonics and Nanoscale Patterning on Flexible Plastic Substrates

The introduction of an ambient-temperature route for integrating high-mobility semiconductors on flexible substrates could enable the development of novel electronic and photonic devices with the potential to impact a broad spectrum of applications. Here we review our recent studies demonstrating that high-quality single-crystal nanowires (NWs) can be assembled onto flexible plastic substrates under ambient conditions to create FETs and light-emitting diodes. We also show that polymer substrates can be patterned through the use of a room temperature nanoimprint lithography technique for the general fabrication of hundred-nanometer scale features, which can be hierarchically patterned to the millimeter scale and integrated with semiconductor NWs to make high-performance FETs. The key to our approach is the separation of the high-temperature synthesis of single-crystal NWs from room temperature solution-based assembly, thus enabling fabrication of single-crystal devices on virtually any substrate. Silicon NW FETs on plastic substrates display mobilities of 200 cm/sup 2/-V/sup -1/-s/sup -1/, rivaling those of single-crystal silicon and exceeding those of state-of-the-art amorphous silicon and organic transistors currently used for flexible electronics. Furthermore, the generality of this bottom-up assembly approach suggests the integration of diverse nanoscale building blocks on a variety of substrates, potentially enabling far-reaching advances in lightweight display, mobile computing, and information storage applications.

WMCSA 2004: 10 Years of Mobile and Ubiquitous Computing

The Sixth IEEE Workshop on Mobile Computing Systems and Applications took place in December 2004 in England’s Lake District. WMCSA 2004 continued the trend of a high-quality interactive workshop focused on mobile and ubiquitous applications, systems, and environments, as well as their underlying state-of-the-art technologies.

A New Semantic Cache Management Method in Mobile Databases

In mobile database systems, caching is a crucial way to improve the performance because a new query can be partially answered locally when the client is continuously moving around. Semantic caching has been paid much attention in traditional database systems. However, the methods of semantic cache management proposed in those systems are not suitable for mobile computing environment. Moreover, although many improved semantic caching strategies for mobile computing application have been proposed in recent years, few papers discussed semantic cache coherence control, which is very important in mobile computing environment. In this paper, we propose some new semantic cache model and management algorithms, which can significantly reduce the unnecessary uplink requests and downlink broadcasts compared to previous schemes. Simulation experiments are carried out to evaluate the proposed strategy.

Human–computer interaction issues for mobile computing in a variable work context

The current paper takes an introspective look at the human–computer interaction (HCI) issues for mobile computing in a variable work context. We catalogue the current research in four major categories. The major findings of our study are following. (1) A majority of HCI issues, about 58%, fall under the category of computer systems and interface architecture implications. (2) 23% of the articles focus on development and implementation issues. (3) 13% of the articles focus on use and context of computer issues. (4) 6% of the articles focus on human characteristics issues. Further, the literature indicates that the field services is a main application of mobile computing (46%) followed by sales force (21%), health care (17%), fieldwork (8%), insurance claims (4%) and journalism (4%).

Conferences - Mobile computing at the beach

The Fifth IEEE Workshop on Mobile Computing Systems and Applications descended on the Beach Resort in Monterey, California, for a series of technical discussions of new research in pervasive and mobile computing.

Architectures and protocols for mobile computing applications: a reconfigurable approach

This work deals with reconfigurable control functions and protocols for supporting mobile computing applications in heterogeneous wireless systems like cellular networks and WLANs. The control functions are implemented in a software module, named Reconfigurable Access module for MObile computiNg applications (RAMON), placed in mobile and/or base stations. RAMON operates on abstract models of the main communication functions of a wireless systems (e.g., transmission over the radio channel, coding end error recovery, capacity sharing and packet scheduling, handover, congestion control, etc.). RAMON algorithms are programmed with reference to the abstract models, independently of specific radio and network technologies. RAMON interactions with a specific wireless access system are conceptually defined by means of parameters that can be measured and controlled, so that the general logic of the module can be posed on top of each system within the constraints and the flexibility provided by the system itself. The implementation of this architectural paradigm requires the definition of specific software adaptation modules between RAMON and each specific system. The reconfigurability of RAMON is exploited to adapt and select the algorithms on the basis of user/application requirements. The paper describes the RAMON architectural model and its control algorithms. Specific examples of adaptation modules are also provided. A selection of performance results achieved by a simulator implementing the RAMON module, the adaptation modules and the main communication functions of UMTS, 802.11 and Bluetooth are shown.

High-Performance Nanowire Electronics and Photonics on Glass and Plastic Substrates

The merger of nanoscale building blocks with flexible and/or low cost substrates could enable the development of high-performance electronic and photonic devices with the potential to impact a broad spectrum of applications. Here we demonstrate that high-quality, single-crystal nanowires can be assembled onto inexpensive glass and flexible plastic substrates to create basic transistor and light-emitting diode devices. In our approach, the high-temperature synthesis of single-crystal nanowires is separated from ambient-temperature solution-based assembly to enable the fabrication of single-crystal-like devices on virtually any substrate. Silicon nanowire field-effect transistors were assembled on glass and plastic substrates and display device parameters rivaling those of single-crystal silicon and exceeding those of state-of-the-art amorphous silicon and organic transistors currently used for flexible electronics on plastic substrates. Nanowire transistor devices have been configured as low-threshold logic elements with gain; moreover, the high-performance characteristics are relatively unaffected by operation in a bent configuration or by repeated bending. The generality of this approach is further illustrated with the assembly of gallium nitride nanowire UV-light-emitting diodes on flexible plastic substrates. These results suggest that nanowires could serve as high-performance building blocks for the next of generation lightweight display, mobile computing, and information storage applications.

A timer-based mobile multicast routing protocol in mobile networks

Mobile computing and multimedia application are two emerging trends in computer systems. Multicasting reduces the amount of multimedia traffics by delivering a single stream of information to many recipients simultaneously. Regarding mobile hosts, however, the naı̈ve deployment of existing multicast routing protocols is not a suitable because they implicitly assume static hosts and do not consider the dynamic changes in the location of group members. In this paper, we present a new efficient mobile multicast routing protocol in terms of tree reconstruction overhead, data delivery length, etc. The proposed protocol introduces FMA (Foreign Multicast Agent) for mobile group membership; JOIN, GROUP timer for mobile multicast routing . The periodic join operation by the two timers makes it possible to utilize the characteristic that the mobile multicasting has according to the speed of mobile hosts. Various performance evaluation results illustrate that the proposed protocol shows performance enhancements over existing protocols.

Programming Ubiquitous and Mobile Computing Applications with TOTA Middleware

Computer-based systems will be increasingly embedded in many of our everyday objects and in much of our environment. Typical systems will be communication enabled and able to interact with each oth...

Programming Ubiquitous and Mobile Computing Applications with TOTA Middleware

Computer-based systems will be increasingly embedded in many of our everyday objects and in much of our environment. Typical systems will be communication enabled and able to interact with each other in the context of complex distributed applications.

The application of mobile computing and technology to health care services

Mobile computing and technology is becoming prevalent in many aspects of private life and public services. This paper presents a discussion of the technology and its application in context of the UKs health care service, and outlines some potential benefits that may result from its integration into existing information systems and architectures. The additional component of ‘mobility’ is believed to provide value to health care services, information systems and ultimately the patient’s experience.

Dynamic coalition formation among rational agents

Dynamic coalition formation (DCF) promises to be well suited for applications of ubiquitous and mobile computing. This article proposes a simulation-based DCF scheme designed to let rational agents form coalitions in dynamic environments.

Chebyshev optimization for the design of broadband beamformers in the near field

The use of microphone arrays for video conferences, hands-free mobile telephony and computer applications has created the demand for near-field broadband beamformer design methods. Here, a general broadband beamformer design problem is formulated as a weighted Chebyshev optimization problem, and a method to solve the resulting functionally-constrained problem is presented. The formulation can also be applied to the design of multidimensional digital finite-impulse response (FIR) filters with an arbitrarily specified amplitude and phase. Numerical results that demonstrate the minimax near-field behavior of the designed beamformers are given.

Applications of wireless research to real industrial problems. Applications of mobile computing and communication

In its Wireless Initiative, the Information Networking Institute deliberately seeks out innovative wireless and mobile application areas in the expectation that hands-on experience with real applications will keep all research work grounded in reality. Since the beginning of the Initiative three applications have been pursued, each incorporating the concepts of one or more researchers, and each addressing an acute problem for a customer organization. The three applications are: The FRIEND System-an application to provide distributed wireless access to different levels of emergency response personnel. These personnel may be first responders (police, fire, emergency medical), field dispatchers, or dispatched personnel. The Health-link System-an application for home health care support. The application initially targets the processes of agency referral and management of regularly scheduled visits by home health care nurses. Later versions will support management of emergency situations. The AMEFS System-an innovative maintenance system for Daimler-Benz (AEG Transportation Systems Inc. Maintenance and Engineering Feedback System-AMEFS) which includes making vehicles able to diagnose and report their operating conditions and a model technician support system. The system will not only simplify access to corporate-wide maintenance knowledge but also feed the technician's experience back into the maintenance system.

Micro standards: IEEE std P1394

Various standards organizations hope to provide a higher speed for the transmission of serial data. One attractive project, proposed IEEE Std P1394, particularly appeals to users because of its convenience and-since it requires fewer driven signals than parallel methods-its lower cost. This alternative transmits serial data with smaller cables and connectors and also applies to emerging plug-and-play standards. Since it assigns device addresses automatically and requires no bus termination, P1394 is much easier to use than several existing parallel data buses. P1394's serial bus supports low-cost desktop and mobile-computing applications. The inclusion of an isochronous data transfer mode makes P1394 especially attractive for use in consumer electronics as well as the more traditional computer environments. Isochronous means regular time measure. Thus, isochronous data transfers at regular time intervals, guaranteeing a latency period in the transfer. >