scholarly journals Effectual Non-Intrusive Minimum-Process Synchronous Checkpointing Protocol for Mobile Distributed Systems

2021 ◽  
pp. 325-331
Author(s):  
Raman Kumar ◽  
Er Jyoti Arora
Keyword(s):  
Distributed Systems ◽  
Communication Complexity ◽  
Optimization Technique ◽  
Mobile Systems ◽  
Global State ◽  
Mobile Nodes ◽  
Computing Systems ◽  
Mobile Hosts ◽  
Minimum Number ◽  
The Cost

While dealing with Mobile Distributed systems, we come across some issues like: mobility, low bandwidth of wireless channels and dearth of stable storage on mobile nodes, disconnections, inadequate battery power and high failure rate of mobile nodes. Minimum-process coordinated checkpointing is considered an attractive methodology to introduce fault tolerance in mobile systems transparently. In this paper, we propose a non-blocking coordinated global state compilation algorithm for mobile computing systems, which requires only a minimum number of processes to take permanent recovery points. We reduce the communication complexity as compared to the Cao-Singhal algorithm [4], while keeping the number of useless recovery points unchanged. Finally, the paper presents an optimization technique, which significantly reduces the number of useless recovery points at the cost of minor increase in the communication complexity. In coordinated global state compilation, if a single process fails to take its tentative recovery point; all the recovery point effort is aborted. We try to reduce this effort by taking soft recovery points in the first phase at Mobile Hosts.

scholarly journals Low-Overhead Minimum-Method Global Snapshot Compilation Protocol for Deterministic Mobile Computing Systems

2021 ◽  
Vol 9 (8) ◽  
pp. 1069-1072
Keyword(s):  
Distributed Systems ◽  
Fault Tolerance ◽  
Mobile Computing ◽  
Distributed Applications ◽  
Battery Life ◽  
Global State ◽  
Mobile Environment ◽  
Computing Systems ◽  
The Cost

CGS-accumulation (Consistent Global State Accumulation) is one of the commonly used method to provide fault tolerance in distributed systems so that the system can operate even if one or more components have failed. However, mobile computing systems are constrained by low bandwidth, mobility, lack of stable storage, frequent disconnections and limited battery life. Hence CGS- accumulation etiquettes which have lesser reinstatement- points are favored in mobile environment. In this paper, we propose a minimum-method coordinated CGS-accumulation etiquette for deterministic distributed applications on mobile computing systems. We eliminate useless reinstatement-points as well as blocking of methods during reinstatement-points at the cost of logging anti- messages of very few messages during CGS-accumulation. We also try to minimize the loss of CGS-accumulation effort when any method miscarries to capture its reinstatement-point in an instigation. In this way, we take care of excessive disappointments during CGS-accumulation. We make logging of anti-messages of very few messages only during CGS-accumulation. We also strive to minimize loss of CGS-accumulation effort.

A MINIMUM-PROCESS COORDINATED CHECKPOINTING PROTOCOL FOR MOBILE COMPUTING SYSTEMS

2008 ◽  
Vol 19 (04) ◽  
pp. 1015-1038 ◽  
Author(s):  
SUNIL KUMAR GUPTA ◽  
R. K. CHAUHAN ◽  
PARVEEN KUMAR
Keyword(s):  
Distributed Systems ◽  
Wireless Channels ◽  
Mobile Nodes ◽  
High Failure Rate ◽  
Computing Systems ◽  
Battery Power ◽  
The Status ◽  
Minimum Number ◽  
Status Information ◽  
Coordinated Checkpointing

Checkpoint is a designated place in a program at which normal process is interrupted specifically to preserve the status information necessary to allow resumption of processing at a later time. A checkpoint algorithm for mobile distributed systems needs to handle many new issues like: mobility, low bandwidth of wireless channels, lack of stable storage on mobile nodes, disconnections, limited battery power and high failure rate of mobile nodes. These issues make traditional checkpointing techniques unsuitable for such environments. Minimum-process coordinated checkpointing is an attractive approach to introduce fault tolerance in mobile distributed systems transparently. This approach is domino-free, requires at most two checkpoints of a process on stable storage, and forces only a minimum number of processes to checkpoint. But, it requires extra synchronization messages, blocking of the underlying computation or taking some useless checkpoints. In this paper, we design a minimum-process checkpointing algorithm for mobile distributed systems, where no useless checkpoint is taken. We reduce the blocking of processes by allowing the processes to do their normal computations, send messages and receive selective messages during their blocking period.

scholarly journals A Low-Cost Hybrid Coordinated Checkpointing Protocol for Mobile Distributed Systems

2008 ◽  
Vol 4 (1) ◽  
pp. 13-32 ◽  
Author(s):  
Parveen Kumar
Keyword(s):  
Distributed Systems ◽  
Low Cost ◽  
Fixed Number ◽  
Mobile Nodes ◽  
Battery Power ◽  
Coordinated Checkpointing ◽  
The Cost ◽  
Coordinated Checkpoint ◽  
Low Activity ◽  
Blocking Algorithm

Mobile distributed systems raise new issues such as mobility, low bandwidth of wireless channels, disconnections, limited battery power and lack of reliable stable storage on mobile nodes. In minimum-process coordinated checkpointing, some processes may not checkpoint for several checkpoint initiations. In the case of a recovery after a fault, such processes may rollback to far earlier checkpointed state and thus may cause greater loss of computation. In all-process coordinated checkpointing, the recovery line is advanced for all processes but the checkpointing overhead may be exceedingly high. To optimize both matrices, the checkpointing overhead and the loss of computation on recovery, we propose a hybrid checkpointing algorithm, wherein an all-process coordinated checkpoint is taken after the execution of minimum-process coordinated checkpointing algorithm for a fixed number of times. Thus, the Mobile nodes with low activity or in doze mode operation may not be disturbed in the case of minimum-process checkpointing and the recovery line is advanced for each process after an all-process checkpoint. Additionally, we try to minimize the information piggybacked onto each computation message. For minimum-process checkpointing, we design a blocking algorithm, where no useless checkpoints are taken and an effort has been made to optimize the blocking of processes. We propose to delay selective messages at the receiver end. By doing so, processes are allowed to perform their normal computation, send messages and partially receive them during their blocking period. The proposed minimum-process blocking algorithm forces zero useless checkpoints at the cost of very small blocking.

Determination of the minimum number of technological bases of a part

2020 ◽  
pp. 73-75
Author(s):  
B.M. Bazrov ◽  
T.M. Gaynutdinov
Keyword(s):  
Cost Price ◽  
Labor Input ◽  
Part Surface ◽  
Technological Base ◽  
Size Accuracy ◽  
Minimum Number ◽  
The Cost ◽  
Input Cost ◽  
Selection Of

The selection of technological bases is considered before the choice of the type of billet and the development of the route of the technological process. A technique is proposed for selecting the minimum number of sets of technological bases according to the criterion of equality in the cost price of manufacturing the part according to the principle of unity and combination of bases at this stage. Keywords: part, surface, coordinating size, accuracy, design and technological base, labor input, cost price. [email protected]

A Harmonic Source Location Method Based on PMU Measurements in Distribution Network

2015 ◽  
Vol 775 ◽  
pp. 409-414
Author(s):  
Bing Jun Li ◽  
Su Quan Zhou ◽  
Xiao Xiang Lun
Keyword(s):  
Power System ◽  
State Estimation ◽  
Distribution Network ◽  
Measured Data ◽  
Optimal Measurement ◽  
Location Method ◽  
Measurement Placement ◽  
Minimum Number ◽  
Harmonic Source ◽  
The Cost

It is of great importance to identify the location of the harmonic sources for the harmonic governance in the power system. Applied with optimal measurement placement (OMP) and harmonic state estimation (HSE), this paper presents a novel process based on PMU measurements to locate the harmonic sources in the distribution network. Considering the cost and the observability, the OMP can provide a scheme of the measurement placement with the minimum number of PMU measurements. In order to simplify the HSE equation, the measured data are converted to the form of voltage by the method proposed in this paper.By solving the HSE equation, the location and magnitude of the harmonic source are evaluated. The methodology is applied to the IEEE 33-bus system, and the obtained results are properly analyzed.

A two-step optimization technique for functions placement, partitioning, and priority assignment in distributed systems

2013 ◽  
Vol 48 (5) ◽  
pp. 121-132 ◽  
Author(s):  
Asma Mehiaoui ◽  
Ernest Wozniak ◽  
Sara Tucci-Piergiovanni ◽  
Chokri Mraidha ◽  
Marco Di Natale ◽  
...  
Keyword(s):  
Distributed Systems ◽  
Optimization Technique ◽  
Priority Assignment

scholarly journals The Development of Patient Scheduling Groups for an Effective Appointment System

2016 ◽  
Vol 07 (01) ◽  
pp. 43-58 ◽  
Author(s):  
Yu Li Huang
Keyword(s):  
Access To Care ◽  
Treatment Time ◽  
Optimization Technique ◽  
Urgent Care ◽  
Patient Scheduling ◽  
Total Cost ◽  
Patient Type ◽  
Clinic Efficiency ◽  
The Cost ◽  
The Impact

SummaryPatient access to care and long wait times has been identified as major problems in outpatient delivery systems. These aspects impact medical staff productivity, service quality, clinic efficiency, and health-care cost.This study proposed to redesign existing patient types into scheduling groups so that the total cost of clinic flow and scheduling flexibility was minimized. The optimal scheduling group aimed to improve clinic efficiency and accessibility.The proposed approach used the simulation optimization technique and was demonstrated in a Primary Care physician clinic. Patient type included, emergency/urgent care (ER/UC), follow-up (FU), new patient (NP), office visit (OV), physical exam (PE), and well child care (WCC). One scheduling group was designed for this physician. The approach steps were to collect physician treatment time data for each patient type, form the possible scheduling groups, simulate daily clinic flow and patient appointment requests, calculate costs of clinic flow as well as appointment flexibility, and find the scheduling group that minimized the total cost.The cost of clinic flow was minimized at the scheduling group of four, an 8.3% reduction from the group of one. The four groups were: 1. WCC, 2. OV, 3. FU and ER/UC, and 4. PE and NP. The cost of flexibility was always minimized at the group of one. The total cost was minimized at the group of two. WCC was considered separate and the others were grouped together. The total cost reduction was 1.3% from the group of one.This study provided an alternative method of redesigning patient scheduling groups to address the impact on both clinic flow and appointment accessibility. Balance between them ensured the feasibility to the recognized issues of patient service and access to care. The robustness of the proposed method on the changes of clinic conditions was also discussed.

scholarly journals An Architecture for Distributed Electronic Documents Storage in Decentralized Blockchain B2B Applications

Computers ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 142
Author(s):  
Obadah Hammoud ◽  
Ivan Tarkhanov ◽  
Artyom Kosmarski
Keyword(s):  
Distributed Systems ◽  
Data Storage ◽  
Distributed Storage ◽  
Distributed Data ◽  
Erasure Coding ◽  
Distributed Data Storage ◽  
Electronic Documents ◽  
File Storage ◽  
Load Balancer ◽  
The Cost

This paper investigates the problem of distributed storage of electronic documents (both metadata and files) in decentralized blockchain-based b2b systems (DApps). The need to reduce the cost of implementing such systems and the insufficient elaboration of the issue of storing big data in DLT are considered. An approach for building such systems is proposed, which allows optimizing the size of the required storage (by using Erasure coding) and simultaneously providing secure data storage in geographically distributed systems of a company, or within a consortium of companies. The novelty of this solution is that we are the first who combine enterprise DLT with distributed file storage, in which the availability of files is controlled. The results of our experiment demonstrate that the speed of the described DApp is comparable to known b2c torrent projects, and subsequently justify the choice of Hyperledger Fabric and Ethereum Enterprise for its use. Obtained test results show that public blockchain networks are not suitable for creating such a b2b system. The proposed system solves the main challenges of distributed data storage by grouping data into clusters and managing them with a load balancer, while preventing data tempering using a blockchain network. The considered DApps storage methodology easily scales horizontally in terms of distributed file storage and can be deployed on cloud computing technologies, while minimizing the required storage space. We compare this approach with known methods of file storage in distributed systems, including central storage, torrents, IPFS, and Storj. The reliability of this approach is calculated and the result is compared to traditional solutions based on full backup.

A Survey of Efficient Trust Management Schemes in Mobile Ad-Hoc Network

2021 ◽  
pp. 151-172
Author(s):  
J. Kaur ◽  
S. Kaur
Keyword(s):  
Trust Management ◽  
Ad Hoc ◽  
Delivery Ratio ◽  
Detection Accuracy ◽  
Mobile Nodes ◽  
Trust Value ◽  
Mobile Hosts ◽  
Wireless Medium ◽  
Mobile Ad Hoc ◽  
Hoc Networks

Mobile Ad Hoc Networks (MANETs) are comprised of an arrangement of self-sorting mobile hosts furnished with wireless interaction devices gathered in groups without the need of any settled framework as well as centralized organization to maintain a system over radio connections. Every mobile node can react as a host and also, the router freely utilizes the wireless medium inside the correspondence range to deal with the interaction between huge quantities of individual mobile nodes by framing a correspondence system and trading the information among them without using any described group of the base station. A trust-based model in MANET estimates and sets up trust relationship among objectives. Trust-based routing is utilized to keep away data from different attackers like a wormhole, DOS, black-hole, selfish attack and so forth. Trust can be executed in different steps like reputation, subjective rationale and from the supposition of the neighboring node. A trust estimation approach not just watches the behavior of neighbor nodes, additionally it screens the transmission of the information packet in the identification of the route for exact estimation of trust value. A survey is carried out to find some of the limitations behind the existing works which has been done by the researchers to implement various approaches thus to build the trust management framework. Through the survey, it is observed that existing works focused only on the authenticated transmission of the message, how it transmits packets to the destination node securely using a trust-based scheme. And also, it is observed that the routing approach only focused on the key management issues. Certain limitation observed in the implemented approaches of existing work loses the reliability of framework. Thus, to withstand these issues it is necessary to establish a reliable security framework that protects the information exchanged among the users in a network while detecting various misbehaving attacks among the users. Confidentiality, as well as the integrity of information, can be secured by combining context-aware access control with trust management. The performance parameters should be evaluated with the previous works packet delivery ratio, packet drop, detection accuracy, number of false positives, and overhead.

Security Issues in Distributed Computing System Models

2017 ◽  
pp. 211-259 ◽  
Author(s):  
Ghada Farouk Elkabbany ◽  
Mohamed Rasslan
Keyword(s):  
Distributed Systems ◽  
Distributed Computing ◽  
Computing System ◽  
Computing Environment ◽  
Distributed Computing Systems ◽  
Computing Systems ◽  
Research Directions ◽  
System Models ◽  
Security Issues ◽  
Systems Security

Distributed computing systems allow homogenous/heterogeneous computers and workstations to act as a computing environment. In this environment, users can uniformly access local and remote resources in order to run processes. Users are not aware of which computers their processes are running on. This might pose some complicated security problems. This chapter provides a security review of distributed systems. It begins with a survey about different and diverse definitions of distributed computing systems in the literature. Different systems are discussed with emphasize on the most recent. Finally, different aspects of distributed systems security and prominent research directions are explored.

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