Group membership in asynchronous distributed environments using logically ordered views

A group membership protocol ensures agreement and consistent commit actions among group members to maintain a sequence of identical group views in spite of continuous changes, either voluntary or otherwise, in processors' membership status. In asynchronous distributed environments, such consistency among group views must be guaranteed using messages over a network which does not bound message delivery times. Assuming a network that provides a reliable, FIFO channel between any pair of processors, one approach to designing such a protocol is to centralize the responsibility to detect changes, ensure agreement, and commit them consistently in a single manager process. This approach is complicated by the fact that a protocol to elect a new manager with a consistent membership proposal must be executed when the manager itself fails. In this report, we present a membership protocol based on ordering of group members in a logical ring that eliminates the need for such centralized responsibility. Agreement and commit actions are token-based and the protocol ensures that no tokens are lost or duplicated due to changes in membership. The cost of committing a change is 2n point-to-point messages over FIFO channels where n is the group size. The protocol correctness has been proven formally. Agreement, Asynchronous, Commit, Distributed, Failure, Group Membership, Logical Ring, Reliable Multicast, TokenMonterey, California. Naval Postgraduate Schoolhttp://archive.org/details/groupmembershipi00shukMonterey, California. Naval Postgraduate SchoolNAApproved for public release; distribution is unlimited

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field

Resume of Shridhar B. Shukla, 1990-05

Naval Postgraduate School Faculty Resum

Resume of Shridhar B. Shukla, 1993-08

Naval Postgraduate School Faculty Resum

Parallel Satellite Orbit Prediction Using a Workstation Cluster

International J. Computer and Mathematics with Applications, 28, (1994), 1–8.In this paper, the benefits of parallel computing using a workstation cluster are explored for satellite orbit prediction. Data and function decomposition techniques are used. Speedup and throughput are the performance metric studied. The software employed for parallelization was the Parallel Virtual Machine (PVM) developed by the Oak Ridge National Laboratory. PVM enables a network of heterogeneous workstations to appear as a parallel multicomputer to the user programs. A speedup of almost 6 was achieved when using 8 SUN workstations

Real-time execution control of task-level data-flow graphs using a compile-time approach

Efficient data-flow implementation requires fast run-time mechanisms to detect and dispatch schedulable tasks. However, the inherent non-determinism in data-flow executions and the requirement of fast, and therefore, simple run- time mechanisms necessitate compile-time support to improve performance. In particular, for data-flow execution of applications, such as signal processing which are characterized by periodically received data, compile-time support can be used to control the run-time behavior to improve the predictability and efficiency. In this report, a compile-time technique that supports a simple run- time mechanism to improve throughput and predictability for a task-level data- flow programming model is described. This technique, called the revolving cylinder analysis, restructures the application, described by a task-level data- flow graph. The restructuring is based on wrapping the projected data-flow execution trace on the curved surface of a cylinder whose area depends upon the number of processors and the sum of the task execution times. The behavior of the restructured graph is shown to be more predictable under the same run-time mechanism than that of the old graph. Results on the performance improvement for two typical signal processing applications, viz., a correlator and a fast Fourier Transform, are presented. The potential of this approach in determining the optimal granularity for an application is also described. Compile-time, Data-flow, Graph Restructuring, Real-time, Run-time, Scheduling, Signal Processing, Throughput, Task-levelNaval Sea Systems Commandhttp://archive.org/details/realtimeexecutio00shukNaval Sea Systems CommandNAApproved for public release; distribution is unlimited

Architecture and protocols for a decentralized group membership service for wide-area networks

Entities cooperating as a group become simpler to construct if they possess access to a membership service to manage and administer the membership information of such groups. This report describes the architecture and design of a wide-area group membership service. Unlike any known membership service, the semce is based on a completely decentralized protocol executed by a hierarchy of servers. This hierarchy permits a clear separation between the membership service infrastructure and support for application groups, permitting global scaleability. The membership protocol itself is executed by a core set of membership servers identified in a group-specific manner, permitting a separate name space, membership scope and partition handling for each group. We describe a suitable application programmer's interface and provide correctness arguments for the protocol. A working implementation of the basic membership protocol is described.http://archive.org/details/architecturendpr109452440

Multicast Tree Construction in Network Topologies with Asymmetric Link Loads

This paper addresses the problem of constructing multicast trees with reservation of resources. The main features of the approach described are that it tolerates asymmetric traffic loads on network links and algorithmically locates data distribution centers for every multiparticipant interaction. A fast and scalable algorithm for locating distribution centers based on the network load and a priori knowledge of participant's locations and resource requirements is given. To explicitly handle cases of disjoint send and receive paths between two nodes, a protocol to build separate send-trees and receive-trees around the centers located in the above manner is given. Simulation results on various topologies are presented showing that, with the above center location mechanism, center-specific trees yield lower tree cost than source-specific trees for many concurrent senders with only a modest increase in the average path length. The use of distribution centers, a priori information, and sensi..

<i style="mso-bidi-font-style:normal"><span style="font-size:11.0pt;font-family:"Times New Roman";mso-fareast-font-family: "Times New Roman";mso-bidi-font-family:Mangal;mso-ansi-language:EN-GB; mso-fareast-language:EN-US;mso-bidi-language:HI" lang="EN-GB">Terminalia arjuna </span></i><span style="font-size:11.0pt;font-family:"Times New Roman";mso-fareast-font-family: "Times New Roman";mso-bidi-font-family:Mangal;mso-ansi-language:EN-GB; mso-fareast-language:EN-US;mso-bidi-language:HI" lang="EN-GB">(Roxb.) Wight & Arn. augments cardioprotection via antioxidant and antiapoptotic cascade in isoproterenol induced cardiotoxicity in rats</span>

810-818<span style="font-size:11.0pt;font-family: " times="" new="" roman";mso-fareast-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:="" hi"="" lang="EN-GB">Worldwide, Ischemic heart disease (IHD) affects a large population. Implication of myocardial infarction (MI) and its multiple pathophysiology in cardiac function is well known. Further, isoproterenol (ISP) is known to induce MI. Today, there is an urgent need for effective drug that could limit the myocardial injury. Therapeutic intervention with antioxidants has been shown useful in preventing the deleterious changes produced by ISP. Here, we investigated the protective effects of oral pre-treatment of hydroalcoholic extract of bark of Terminalia arjuna (HETA) on biochemical and apoptotic changes during cardiotoxicity induced by isoproterenol (ISP) in rats. HETA was orally administered at a dose of 100, 200 and 400 mg/kg body wt., for 30 days with concurrent administration of ISP (85 mg/kg body wt.) on days 28th and 29th at an interval of 24 h. ISP caused deleterious changes in the myocardium and significantly increased (P <0.05) malondialdehyde, serum glutamate oxaloacitate transaminase, creatine kinase-MB, lactate dehydrogenase and troponin-I. However, it significantly decreased (P <0.05) glutathione and superoxide dismutase compared to healthy control. Oral pre-treatment of HETA for 30 days significantly decreased (P <0.05) the biochemical parameters of oxidative stress and cardiac markers as compared to ISP control. Histopathological findings also revealed that architecture of the myocardium was restored towards normal in HETA pre-treated group. Overall, the present study has shown that the hydroalcoholic extract of bark of T. arjuna (HETA) attenuates oxidative stress, apoptosis and improves antioxidant status in ISP-induced cardiotoxicity in rats.</span