Digital-filter functions with fast coefficient implementation: an addendum

Five parallel transfer function formulations for digital filters are given. The coefficients in these allow a simple and very fast multiplication process. These functions provide a maximum bandwidth of about double that of an earlier set.     

Efficient algorithms for optimistic crash recovery

Summary Recovery from transient processor failures can be achieved by using optimistic message logging and checkpointing. The faulty processorsroll back, and some/all of the non-faulty processors also may have to roll back. This paper formulates the rollback problem as a closure problem. A centralized closure algorithm is presented together with two efficient distributed implementations. Several related problems are also considered and distributed algorithms are presented for solving them. S. Venkatesan received the B. Tech. and M. Tech degrees from the Indian Institute of Technology, Madras in 1981 and 1983, respectively and the M.S. and Ph.D. degrees in Computer Science from the University of Pittsburgh in 1985 and 1988. He joined the University of Texas at Dallas in January 1989, where he is currently an Assistant Professor of Computer Science. His research interests are in fault-tolerant distributed systems, distributed algorithms, testing and debugging distributed programs, fault-tolerant telecommunication networks, and mobile computing. Tony Tony-Ying Juang is an Associate Professor of Computer Science at the Chung-Hwa Polytechnic Institute. He received the B.S. degree in Naval Architecture from the National Taiwan University in 1983 and his M.S. and Ph.D. degrees in Computer Science from the University of Texas at Dallas in 1989 and 1992, respectively. His research interests include distributed algorithms, fault-tolerant distributed computing, distributed operating systems and computer communications.This research was supported in part by NSF under Grant No. CCR-9110177 and by the Texas Advanced Technology Program under Grant No. 9741-036     

On the non-approximability of points-to analysis

Determining points-to sets is an important static-analysis problem. Most of the classic static analyses (used e.g., by compilers or in programming environments) rely on knowing which variables might be used or defined by each expression in a program. In the presence of pointers, the use/def set of an expression like *p = *q can only be determined given (safe) points-to sets for p and q. Previous work has shown that both precise flow-sensitive and precise flow-insensitive pointer analysis is NP-Hard, even when restricted to single-procedure programs with no dynamic memory allocation. In this paper, we show that it is not even possible to compute good approximations to the precise solutions (i.e., to compute points-to sets whose sizes are within a constant factor of the sizes of the precise points-to sets) unless P=NP. Received: 1 November 2001 / 4 February 2002     

An experimental investigation of YBa2Cu3O7 films at millimeter-wave frequencies

We have measured the millimeter-wave (100 GHz) surface resistance of high-quality laserdeposited YBa₂Cu₃O₇ films on SrTiO₃ and LaA10₃ substrates. Due to finite film thickness, radiation losses are important in the normal state and in the superconducting state nearT _c. These effects are calculated andR _s characteristic of the ohmics losses in the film are extracted from the data. The surface resistanceR _s drops rapidly atT _c, and a detailed comparison with calculations which include finite mean free path effects suggests a gap which exceeds the weak coupling BCS limit.     

Cardiac disease in chronic uremia: management

Heart disease is a common cause of morbidity in end-stage renal disease (ESRD) patients. The management of heart disease in these patients requires a multidimensional approach to the management of heart failure, coronary disease, and arrhythmias, and to risk factors such as hypertension, anemia, secondary hyperparathyroidism, and electrolyte/acid-base disturbances. Coronary artery disease management includes use of antianginal drugs and revascularization of coronary arteries with angioplasty +/- stent placement or coronary artery bypass grafting. The long-term outcomes of these procedures need to be assessed and improved. Hypertension occupies a major role in the pathogenesis of heart disease in ESRD, and early and adequate control of hypertension is likely to have a major impact on the progression of cardiac disease. This entails the achievement of optimal volume status, combined with the appropriate use of antihypertensive agents such as calcium channel blockers, beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, vasodilators, alpha-blockers, and central sympatholytic drugs. In ESRD patients, specific dialysis-related complications such as intradialytic hypotension and pericardial effusion may have additional effects on cardiac function and require attention. The choice of dialysate composition and membrane may influence clinical outcomes with specific effects on cardiac performance.     

A Hybrid RF and Vision Aware Fusion Scheme for Multi-Sensor Wireless Capsule Endoscopic Localization

A huge torrent of data traffic is generated from various heterogeneous applications and services at the Internet backbone. In general, at the backbone, all such applications and services are allocated spectral resources under a shared spectrum environment within elastic optical networks (EONs). In such a fully shared environment, connection requests (CRs) belonging to different traffic profiles compete for spectral resources. Hence, it is very challenging for network operators to resolve resource conflict that occur at the time of provisioning resources to such CRs. The heterogeneous traffic profile (HTP) considered in this work includes permanent lightpath demands (PLDs) and scheduled lightpath demands (SLDs). We propose various distance adaptive routing and spectrum assignment (DA-RSA) heuristics to resolve resource conflict among these two traffic profiles in EONs under a full sharing environment. Conventionally, preemption was the only technique to resolve such resource conflict among HTPs. Since preemption involves the overhead of selecting CRs to be preempted and then deallocating the resources given to those CRs, excessive preemption adversely affects the performance of the network. Therefore, in this work, we utilized bandwidth splitting as a solution to resolve resource conflict among HTPs under such a shared environment in EONs. Moreover, an integrated solution consisting of splitting and preemption is also proposed. We refer to this new integration as flow-based preemption. Our simulation results demonstrate that bandwidth splitting-based heuristics yield significant improvement in terms of the amount of bandwidth accepted in the network, link and node utilization ratio, number of transponders utilized and the amount of bandwidth dropped due to preemption. Moreover, the flow-based preemption approach is proved to be superior in performance amongst all proposed strategies.