• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권6호
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• pp.1357-1378
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• 2013

Energy constraint of wireless sensor networks makes energy saving and prolonging the network lifetime become the most important goals of routing protocols. In this paper, we propose an Energy Efficient Chain-based Routing Protocol (EECRP) for wireless sensor networks to minimize energy consumption and transmission delay. EECRP organizes sensor nodes into a set of horizontal chains and a vertical chain. Chain heads are elected based on the residual energy of nodes and distance from the header of upper level. In each horizontal chain, sensor nodes transmit their data to their own chain head based on chain routing mechanism. EECRP also adopts a chain-based data transmission mechanism for sending data packets from the chain heads to the base station. The simulation results show that EECRP outperforms LEACH, PEGASIS and ECCP in terms of network lifetime, energy consumption, number of data messages received at the base station, transmission delay and especially energy${\times}$delay metric.

• Management Science and Financial Engineering
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• 제10권2호
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• pp.1-28
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• 2004

The integrated supply chain of business partners for e-Commerce in cyber space is defined as Logistics Chain if the cooperative activities are logistics-related. Logistics Chain could be managed effectively and efficiently by cooperative technologies of logistics chain execution. In this paper, we propose a routing and scheduling algorithm based on the Tabu search by adding geographical information into existing constraint for pick-up and delivery process to minimize service time and cost in logistics chain. And, we also consider an uncertainty processing for the tracing of moving object to control pick-up and delivery vehicles based on GPS/GIS/ITS. Uncertainty processing is required to minimize amount of telecommunication and database on vehicles tracing. Finally, we describe the Logistics Chain Execution (LCE) system to perform plan and control activities for postal logistics chain. To evaluate practical effects of the routing and scheduling system, we perform a pretest for the performance of the tabu search algorithm. And then we compare our result with the result of the pick-up and delivery routing plan generated manually by postmen.

• JSTS:Journal of Semiconductor Technology and Science
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• 제16권5호
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• pp.582-594
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• 2016

Various test data compression techniques have been developed to reduce the test costs of system-on-a-chips. In this paper, a scan chain reordering algorithm for code-based test data compression techniques is proposed. Scan cells within an acceptable relocation distance are ranked to reduce the number of conflicts in all test patterns and rearranged by a positioning algorithm to minimize the routing overhead. The proposed method is demonstrated on ISCAS '89 benchmark circuits with their physical layout by using a 180 nm CMOS process library. Significant improvements are observed in compression ratio and test power consumption with minor routing overhead.

• 산업공학
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• 제22권2호
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• pp.153-164
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• 2009

An effective management for reverse flows of products such as reuse, repair and disposal, has become an important issue for every aspect of business. In this paper, we study the Location-Routing Problem (LRP) in the multi-stage closed-loop supply chain network. The closed-loop supply chain in this study integrated both forward and reverse flows. In forward flow, a factory, Distribution Center (DC) and retailer are considered as usual. Additionally in reverse flow, we consider the Central Returns collection Center (CRC) and disposal facility. We propose a mixed integer programming model for the design of closed-loop supply chain integrating both forward and reverse flows. Since the LRP belongs to an NP-hard problem, we suggest a heuristic algorithm based on genetic algorithm. For some test problems, we found the optimal locations and routes by changing the numbers of retailers and facility candidates. Furthermore, we compare the efficiencies between open-loop and closed-loop supply chain networks. The results show that the closed-loop design is better than the open one in respect to the total routing distance and cost. This phenomenon enlarges the cut down effect on cost as an experimental space become larger.

• 정보보호학회논문지
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• 제13권2호
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• pp.31-40
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• 2003

인터넷 상에서의 보안문제는 거의 대부분이 사용자 데이터에 대한 보안에 초점이 맞추어져 있는 반면에, 인터넷의 원활한 운영에 중요한 골격을 이루는 라우팅 프로토콜의 안전성에 대한 연구는 그리 폭 넓게 행해지고 있지는 않다. 본 논문에서는 현재 인터넷에서 가장 보편적으로 사용되고 있는 Link-State 라우팅 프로토콜의 보안상의 문제점을 지적하고, 이를 위해서 제안된 기존의 일부 인증 메커니즘들의 기능 및 성능을 보완, 확장한 새로운 라우팅 메시지 인증 메커니즘을 제안한다. 이를 위해서 안전성 증명이 가능한 이중 해쉬체인의 개념을 도입하고 이에 기반을 둔 세션 해쉬체인을 통해서 라우팅 메시지에 대한 무결성 및 근원지 인증 서비스를 제공하는 방안을 소개한다.

• 한국전자통신학회논문지
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• 제18권4호
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• pp.579-586
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• 2023

무선 센서 네트워크(Wireless Sensor Network : WSN)는 저가의 소형 센서를 활용해서 무선으로 사용되기 때문에 제한된 배터리 전력을 가지고 있다. 배터리를 교체할 수 없으므로 센서 노드의 수명은 배터리의 수명과 직결되므로 전력을 효율적으로 사용하여 네트워크의 수명을 극대화해야 한다. 본 연구에서는 대표적인 에너지 효율적 라우팅 프로토콜인 PEGASIS(: Power-Efficient Gathering in Sensor Information System)를 기반으로 싱크 노드로부터의 거리에 따라 계층화하여 하나의 체인이 아닌 다중 체인을 구성하는 프로토콜을 제안한다. 제안하는 프로토콜은 노드 간 전송 거리를 줄여서 불필요한 에너지 소모를 막아 네트워크 수명을 높일 수 있음을 확인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권7호
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• pp.1735-1755
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• 2012

Wireless sensor networks (WSNs) are becoming increasingly attractive for a variety of applications and have become a hot research area. Routing is a key technology in WSNs and can be coarsely divided into two categories: flat routing and hierarchical routing. In a flat topology, all nodes perform the same task and have the same functionality in the network. In contrast, nodes in a hierarchical topology perform different tasks in WSNs and are typically organized into lots of clusters according to specific requirements or metrics. Owing to a variety of advantages, clustering routing protocols are becoming an active branch of routing technology in WSNs. In this paper, we present an overview on clustering routing algorithms for WSNs with focus on differentiating them according to diverse cluster shapes. We outline the main advantages of clustering and discuss the classification of clustering routing protocols in WSNs. In particular, we systematically analyze the typical clustering routing protocols in WSNs and compare the different approaches based on various metrics. Finally, we conclude the paper with some open questions.

• 디지털산업정보학회논문지
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• 제16권2호
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• pp.61-68
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• 2020

Nuclear power plants have a lower cost of power generation, and they are more eco-friendly than other power generation plants. Also, we need to prepare nuclear plant accidents because of their severe damage. In the event of a safety accident, such as a radiation leak, by applying a wireless sensor network to a nuclear power plant, many sensor nodes can be used to monitor radiation and transmit information to an external base station to appropriately respond to the accident. However, applying a wireless sensor network to nuclear power plants requires routing protocols that consider the sensor network size and bypass obstacles such as plant buildings. In general, the hierarchical-based routing protocols are efficient in energy consumption. In this study, we look into the problems that may occur if hierarchical-based routing protocols are applied to nuclear power plants and propose improved routing protocols to solve these problems. Simulation results show that the proposed routing protocol is more effective in energy consumption than the existing LEACH protocol.

• 한국정보통신학회논문지
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• 제13권11호
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• pp.2459-2464
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• 2009

센서네트워크에서는 패킷 포워딩과 라우팅 기능을 전담하는 노드나 서버가 존재하지 않고 네트워크 통신에 참여하는 센서노드들이 이러한 기능을 수행한다. 따라서 센서노드들이 패킷 포워딩과 라우팅 과정에서 패킷의 위변조에 대한 공격이 취약하다. 이의 해결책으로 라우팅과 포워딩 메시지에 대한 인증과 무결성을 보장하는 보안기능이 요구된다. 이를 위해서 공개키기반 전자서명 모델에 비해서 디지털 서명을 생성하고 검증하는데 계산적인 부담이 적은 해쉬체인 기반 디지털서명 모델을 제안하고 연산횟수의 비교를 통하여 모델의 적합성을 검증하였다.

• 한국멀티미디어학회논문지
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• 제12권9호
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• pp.1273-1287
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• 2009

Chain-based protocol방법 중의 하나인 PEGASIS는 모든 노드들의 공평한 에너지 소모를 유도 할 수 있지만 BS(Base station)로부터 멀리 떨어진 노드들 중에서 HEAD가 선택될 경우에는 데이터 전송 시에 심각한 에너지 소모와 불필요한 노드들 간의 데이터 이동이 발생하게 된다. 본 논문에서는 이러한 문제점을 해결하기 위해 PEGASIS의 greedy알고리즘을 응용하고, BS를 기준으로 주변 node들과의 거리를 비교하여 에너지 소모를 줄일 수 있는 프로토콜인 DERP(Distance-based Energy efficient routing protocol)을 제안한다. DERP의 기법은 예비헤드(P-HD)노드를 선택하여 보다 효율적인 클러스터 구조를 생성할 수 있는 방법이다. 아울러 더 큰 센서 필드에서의 확장을 위해서 PEGASIS와 제안방법에서 기본이 되는 single-hop 기반의 통신을 HEAD와 BS와의 거리에 따른 relay노드를 선택함으로서 multi-hop 기반의 통신으로 변환하여 에너지 소모를 줄일 수 있는 방법을 추가하였다. DERP의 시뮬레이션 결과 값으로 에너지 효율은 기존의 PEGASIS방법에 비해 최고 80%정도까지의 에너지 효율이 있는 것으로 나타났으며, 데이터 전송 지연 역시 감소하는 것으로 확인 되었다.