611810
G-REMiT: An algorithm for building energy efficient multicast trees in wireless ad hoc networks
In this paper, we propose a distributed algorithm called G-REMiT for building an energy efficient multicast tree in a wireless ad hoc network (WANET). G-REMiT employs a more realistic energy consumption model for wireless communication which takes into account not only the energy losses due to radio propagation but also the energy losses in the transceiver electronics. We evaluate the performance of the protocol using two energy consumption model: long range radio and short range radio. We show that for long range radio model, G-REMiT algorithm can achieve better performance than other proposals such as MLU, MLiMST and MIP, and the energy overhead of for executing G-REMiT is negligible compared with the total energy consumption for the multicast communication. For short range radio, we find that existing energy saving scheme by adjusting node's transmission power is not suitable.
1274772
Supporting persistent social groups in ubiquitous computing environments using context-aware ephemeral group service
We analyze the role of the social group in a ubiquitous computing (Ubicomp) environment as a source of contextual information. A model is presented to address the social group member's perceptions of how devices in a ubicomp environment should aid them in collaboration. Based on the model a distributed context-aware group membership management scheme is developed. We then present a prototype implementation for a context-aware ephemeral group membership management scheme, along with a sample application, and experimental results that demonstrate the feasibility of our system.
3266186
e3D: an energy-efficient routing algorithm for wireless sensor networks
One of the limitations of wireless sensor nodes is their inherent limited energy resource. Besides maximizing the lifetime of the sensor node, it is preferable to distribute the energy dissipated throughout the wireless sensor network in order to minimize maintenance and maximize overall system performance. Any communication protocol that involves synchronization of peer nodes incurs some overhead for setting up the communication. We introduce a new algorithm, e3D (energy-efficient distributed dynamic diffusion routing algorithm), and compare it to two other algorithms, namely directed, and random clustering communication. We take into account the setup costs and analyze the energy-efficiency and the useful lifetime of the system. We compare the algorithms in terms of system lifetime, power dissipation distribution, cost of synchronization, and simplicity of the algorithm. Our simulation results show that e3D performs comparable to its optimal counterpart while having significantly less overhead.
2580676
Adaptive Distributed Dynamic Channel Allocation for Wireless Networks
Channel allocation schemes in a mobile computing (wireless) environment can be either static or dynamic. Static allocation offers negligible channel acquisition time and zero message complexity and works well at a low system load; the performance steadily decreases as system load increases since many calls are dropped. In the case of even temporary hot spots many calls may be dropped by a heavily loaded switching station even when there are enough idle channels in the interference region of that station. On the other hand, dynamic schemes provide better utilization of the channels at higher loads albeit at the cost of higher channel acquisition time and some additional control messages. Our purpose in the present paper is to propose a combined channel allocation scheme so that each switching station can tune to its own load independent of other stations in its interference region; the objective is to minimize the call drop rate and at the same time maintain a minimum average channel acquisition time and minimum control message complexity.
12873659
TARA: Thermal-Aware Routing Algorithm for Implanted Sensor Networks
Implanted biological sensors are a special class of wireless sensor networks that are used in-vivo for various medical applications. One of the major challenges of continuous in-vivo sensing is the heat generated by the implanted sensors due to communication radiation and circuitry power consumption. This paper addresses the issues of routing in implanted sensor networks. We propose a thermal-aware routing protocol that routes the data away from high temperature areas (hot spots). With this protocol each node estimates temperature change of its neighbors and routes packets around the hot spot area by a withdraw strategy. The proposed protocol can achieve a better balance of temperature rise and only experience a modest increased delay compared with shortest hop, but thermal-awareness also indicates the capability of load balance, which leads to less packet loss in high load situations.
384064
Proximity based access control in smart-emergency departments
In this paper, we propose a proximity based automated access control (PBAC) model for smart-ED environments which improves the existing ED work-flow by automating mundane administrative procedure for secure information access, allowing caregivers to focus on the treatment of patients. The proposed access model builds on the traditional role-based access control model and extends it by including multiple authentication levels for preventing unauthorized access. We also provide a semi-formal specification for the PBAC model. We further validate it using ultra-wide-band (UWB) based prototype which was tested in ED
8584813
Generation of alternative feature-based models and precedence orderings for machining applications
Incre=ing global competition is challenging the U.S. manufacturing industry to bring competitively-priced, well-designed and well-manufactured products to market in a timely fashion. Since decisions made during the design stage can have significant effects on product cost, quality, and lead time, increasing research attention is being given to integrating engineering design and manufacturing, with a focus on design for manufacturability. Consider the task of designing and manufacturing machined parts. Often there can be several different ways to machine a part. Which way is best depends on several factors, including dimensions, tolerances, surface finishes, availability of machine tools and cutting tools, fixturability, and optimization criteria. Thus, to evaluate the manufacturability of the proposed design, we may need to consider more than one way to machine it. This paper outlines our approach for generating and evaluating alternative ways to machine a part. For additional details, see [1]; for other related work, see [2, 3].
16013811
A comprehensive fault macromodel for opamps
In this paper, a comprehensive macromodel for transistor level faults in an operational amplifier is developed. With the observation that faulty behavior at output may result from interfacing error in addition to the faulty component, parameters associated with input and output characteristics are incorporated. Test generation and fault classification are addressed for stand-alone opamps. A high fault coverage is achieved by a proposed testing strategy. Transistor level short/bridging faults are analyzed and classified into catastrophic faults and parametric faults. Based on the macromodels for parametric faults, faults simulation is performed for an active filter. We found many parametric faults in the active filter cannot be detected by traditional functional testing. A DFT scheme alone with a current testing strategy to improve fault coverage is proposed.
18759063
The Software Concordance: using a uniform document model to integrate program analysis and hypermedia
Since the source code is only one of many types of documents that must be maintained as a software system evolves, modern software development could be improved by better interoperability between source code and other software documents. The Software Concordance is a prototype programming environment that uses hypermedia services and a uniform document model to achieve this interoperability. The Software Concordance editor allows developers to enhance their inline documentation with multimedia objects and hyperlinks, while still supporting advanced program analysis including lexing, parsing and type checking. We motivate the need for environments like the Software Concordance, describe the design and implementation of its program editor, and discuss lessons learned while creating it. The system is based on a uniform, Web compatible document model for both program source code and nonprogram software documents and a corresponding API. Important technical problems addressed by this research include creating a persistent representation of program lexemes that the analysis suite considers to be ephemeral (such as keywords), providing a simple incremental parsing system, and embedding multimedia in source code without disrupting program analysis. Based on insight gained in the process of implementing the document API, a new approach to the design of a more suitable program analysis infrastructure is suggested.
37175673
A methodology to design efficient BIST test pattern generators
This paper describes a new technique to design efficient test pattern generators (TPGs) for built-in self-test (BIST). The proposed technique identifies compatible circuit inputs that can be connected to the same TPG stage in the test mode. Compatibility between circuit inputs is determined by analyzing the circuit function to guarantee coverage of all faults in a given target fault set. Unlike pseudo-exhaustive testing, circuit inputs that fanout to the same output can be compatible, provided that connecting them to the same TPG stage does not cause any loss of fault coverage. Experimental results show that TPGs designed by the proposed technique achieve 100% stuck-at fault coverage in practical test length (/spl les/2/sup 28/) with low hardware overhead and performance penalty for a wide range of benchmark circuits.
12850641
Fault-oriented Test Generation for Multicast Routing Protocol Design
We present a new algorithm for automatic test generation for multicast routing. Our algorithm processes a finite state machine (FSM) model of the protocol and uses a mix of forward and backward search techniques to generate the tests. The output tests include a set of topologies, protocol events and network failures, that lead to violation of protocol correctness and behavioral requirements. We target protocol robustness in specific, and do not attempt to verify other properties in this paper. We apply our method to a multicast routing protocol; PIM-DM, and investigate its behavior in the presence of selective packet loss on LANs and router crashes. Our study unveils several robustness violations in PIM-DM, for which we suggest fixes with the aid of the presented algorithm.