• KIPS Transactions on Computer and Communication Systems
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• v.5 no.12
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• pp.455-462
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• 2016

Wireless sensor networks have been researched to gather data about events on sensor fields from sources at sinks. Multipath routing is one of attractive approaches to reliably send data against the problem of frequent breakages on paths from sources to sinks due to node and link failures. As mobile events such as humans, animals, and vehicles are considered, sources may be continuously generated according to the movement of the mobile event. Thus, mobile events provide new challenging issue in multipath routing. However, the research on multipath routing mainly focus on both efficient multipath construction from sources to static sinks and fast multipath reconstruction against path breakages. Accordingly, the previous multipath routing protocols request each source continuously generated by a mobile event to construct individual multipath from the source to sinks. This induces the increase of multipath construction cost in the previous protocols in proportion to the number of source. Therefore, we propose efficient multipath routing protocol for supporting continuous sources generated by mobile events. In the proposed protocol, new source efficiently reconstructs its multipath by exploiting the existing multipath of previous sources. To do this, the proposed protocol selects one among three reconstruction methods: a local reconstruction, a global partial one, and a global full one. For a selection decision, we provide an analytical energy consumption cost model that calculates the summation of both the multipath reconstruction cost and the data forwarding cost. Simulation results show that the proposed protocol has better performance than the previous protocol to provide multipath routing for mobile events.

• Journal of information and communication convergence engineering
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• v.7 no.4
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• pp.570-575
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• 2009

This paper describes an implementation of project-based learning in routing design course. The total students who enrolled in the class were 48 and were divided into groups of 3~4 students. At the beginning of the course, a survey was conducted to check the student's level of back ground knowledge acquired from the prerequisite courses. At the end of the curse, we also conducted a survey to evaluate the effect of project-based learning. According to the end of course survey, the course was helpful to identify the problems to solve by themselves, to develop the problem solving ability, and to understand the global picture of the subject by integrating knowledge of each chapter into a project. The survey also shows that students recognized the importance of the teamwork skill throughout the project activity.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.5
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• pp.145-151
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• 1989

A new preprocess technique is presented which can improve the routing efficiency in the gate array layout designs. In order to resolve the cycle problem in the detailed routing, we exchange the logically equivalent pins in each channel. The signal nets are divided, and doubly connected signal net components are removed, so that the increase in the number of tracks can be controlled.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1732-1735
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• 2002

A $\kappa$-side switch box with W terminals on each side is said to be hyper universal, denoted by ($\kappa$, W)-HUSB, if it is routable for any global .outing with density at most W. In [5], we have proposed a switch box design strategy and designed a near optimum (4, W)-HUSB F(W) with 6.W switches. In this paper, we design, analyze and implement an efficient detailed routing algorithm for the S-box F(W). This router. can accommodate all routing requirement topologies.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.1529-1532
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• 2004

A Mobile Ad Hoc NETwork (MANET) is a collection of wireless mobile nodes that forms a temporary network without the need for any existing network infrastructure or centralized administration. Therefore, such a network is designed to operate in a highly dynamic environment due to node mobility. In mobile ad hoc network, frequent topological changes cause routing a challenging problem and without the complete view of the network topology, establishing the shortest path from the source node to the destination node is difficult. In this paper, we suggest a routing approach which utilizes location information to setup the shortest possible path between the source node and the destination node. Location information is obtained through Global Positioning System (GPS) and this geographical coordinate information of the destination node is used by the source node and intermediate nodes receiving route request messages to determine the shortest path to the destination from current node.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.11
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• pp.140-151
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• 1996

In this study, we designed the routing structure and logic block of a SRAM cell-based FPGA with symmetrical-array architecture. The designed routing structure is composed of switch matrices, routing channels and I/O blocks, and the routing channels can be subdivided into single length channels, double length channels and global length channels. The interconnection between wires is made through SRAM cell-controlled pass transistors. To reduce the signal delay in pass transistors, we proposed a scheme raising the gate-control voltage to 7V. The designed SRAM cells have built-in shift register capability, so there is no need for separate shift registers. We designed SRAM cells in the LUTs(look-up tables) to enable the wirte operations to be performed synchronously with the clock for ease of system application. Each logic block (LFU) has four 4-input LUTs, flip-flops and other gates, and the LUTs can be used a sSRAM memory. The LFU also has a dedicated carry logic, so a 4-bit adder can be implemented in one LFU. We designed our FPGA using 0.6.mu.m CMOS technology, and simulation shows proper operation of a 4 bit counter at 100MHz.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.822-825
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• 2007

현재 인터넷 아키텍처가 가지고 있는 가장 큰 문제는 routing과 addressing의 핵심으로 사용되는 IP 주소의 의미의 중복 (overloading semantics)이다. 즉 IP 주소는 라우팅을 위한 정보 (how), 단말의 위치 정보 (where), 그리고 이 외에 전송 계층 상위에서 사용되는 단말의 식별자 정보(who)로 사용되며, 이 의미 중복은 결국 global routing의 scalability문제를 발생시키게 된다. 즉 이러한 IP 주소의 의미 중복을 분리한다면 멀티호밍, Traffic engineering, 그리고 renumbering 등을 scalability에 영향을 주지 않고 이것들을 지원할 수 있게 되는 것이다. IETF는 이러한 라우팅과 어드레싱의 확장성 문제를 해결하기 위하여 68차 IETF 회의에서 ROAP (ROuing and Addressing Problem) BoF (Birds of a Feather) 회의를 공식적으로 개최 하였으며, 이를 통해 결정된 사항은 새로운 인터넷 아키텍처를 설계하기 위해 식별자(Identifier)와 위치정보(locator)를 분리하는 구조(ID/Loc 분리) 또는 다중 계층의 위치정보 획득이 가능한 구조(Multi-level locator design)로의 새로운 아키텍처를 만드는 것이다. 이 작업은 ROPA BoF회의 이후 IRTF의 RRG (Routing Research Group)에서 계속적으로 진행되고 있으며, 현재 관련 많은 솔루션들이 나온 상황이다. 본 논문은 이러한 ROAP에 관한 기본적인 설명과 함께, 문제점 그리고 논의되고 있는 솔루션들의 분류, 목적, 그리고 공통 이슈들에 대한 최근 동향을 설명한다.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10d
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• pp.240-243
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• 2007

Geographic routing has been considered as an efficient simple, and scalable routing protocol for wireless sensor networks since it exploits pure location information instead of global topology information to route data packets. Geographic routing requires the sources nodes to be aware of the location of the sinks. In this paper, we propose a scheme named Sink Location Service for geographic routing in wireless Sensor Networks, in which the source nodes can get and update the location of sinks with low overhead. In this scheme, a source and a sink send data announcement and query messages along two paths respectively by geographic routing. The node located on the crossing point of the two paths informs the source about the location of the sink. Then the source can send data packet to the sink by geographic routing. How to guarantee that these two paths have at least one crossing point in any irregular profile of sensor network is the challenge of this paper.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.1
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• pp.108-113
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• 2012

Routing paths are mightily important for the network security in WSNs. To maintain such routing paths, sustained path re-selection and path management are needed. Region segmentation based path selection method (RSPSM) provides a path selection method that a sensor network is divided into several subregions, so that the regional path selection and path management are available. Therefore, RSPSM can reduce energy consumption when the path re-selection process is executed. However, it is hard to guarantee optimized secure routing path at all times since the information using the path re-selection process is limited in scope. In this paper, we propose partial path selection method in each subregion using preselected partial paths made by RSPSM for routing path optimization in SEF based sensor networks. In the proposed method, the base station collects the information of the all partial paths from every subregion and then, evaluates all the candidates that can be the optimized routing path for each node using a evaluation function. After the evaluation process is done, the result is sent to each super DN using the global routing path information (GPI) message. Thus, each super DN provides the optimized secure routing paths using the GPI. We show the effectiveness of the proposed method via the simulation results. We expect that our method can be useful for the improvement of RSPSM.

• Journal of Korea Water Resources Association
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• v.34 no.5
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• pp.543-549
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• 2001

This research estimated stream discharges indirectly by hydraulic channel routing. Only stage data from three stage stations and river cross section data were used to estimate Manning roughness coefficients and to compute stream discharges. When the discharges were estimated a stage-stage set of conditions was used for upstream-downstream boundary conditions. The research used the data from the upper Mississippi River. The hydraulic channel routings were performed by DWOPER (operational dynamic wave model). The global optimization program of SCE-UA was used to improve the roughness coefficient estimation module of the modified Newton-Raphson method in DWOPER. The results from SCE-US were better. For the case study of a flood, most estimated discharges except a few show errors within 10%.