• School Mathematics
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• v.14 no.4
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• pp.445-468
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• 2012

This study is tried in order to link informal arithmetic reasoning to formal algebraic reasoning. In this study, we investigated elementary school student's non-formal algebraic reasoning used in algebraic problem solving. The result of we investigated algebraic reasoning of 839 students from grade 1 to 6 in two schools, Korea, we could recognize that they used various arithmetic reasoning and pre-formal algebraic reasoning which is the other than that is proposed in the text book in word problem solving related to the linear systems of equation. Reasoning strategies were diverse depending on structure of meaning and operational of problems. And we analyzed the cause of failure of reasoning in algebraic problem solving. Especially, 'quantitative reasoning', 'proportional reasoning' are turned into 'non-formal method of substitution' and 'non-formal method of addition and subtraction'. We discussed possibilities that we are able to connect these pre-formal algebraic reasoning to formal algebraic reasoning.

• The KIPS Transactions:PartC
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• v.12C no.4 s.100
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• pp.481-488
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• 2005

The Mobile W provides an efficient and scalable mechanism for host mobility within the Internet. However, the mobility implies higher security risks than static operations in fixed networks. In this paper, the Mobile IP has been adapted to allow AAA protocol that supports authentication, authorization, and accounting(AAA) for security and collection for accounting information of network usage by mobile nodes(MNs). For this goal, we Propose the boundary tone overlapped network structure while solidifying the security for the authentication of an MN. That is, the Proposed scheme delivers the session keys at the wired link for MN's security instead of the wireless one, so that it provides a fast and seamless handoff mechanism. According to the analysis of modeling result, the proposed mechanism compared to the existing session key reuse method is up to about $40\%$ better in terms of normalized surcharge for the handoff failure rate that considers handoff total time.

• KIISE Transactions on Computing Practices
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• v.20 no.12
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• pp.694-699
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• 2014

In mobile ad-hoc networks (MANET), the network topology and neighboring nodes change frequently, since MANET is composed of nodes that have mobility without a fixed network infrastructure. The AODV routing protocol is advantageous for MANET, but AODV has a delay in the transmission of data packets because AODV can not transmit data during route recovery. This paper proposes solving the above problem of AODV by using a bypass generation mechanism for data transmission during route recovery. For further improvement, additional mechanisms that coordinate the reception threshold of a hello packet are proposed in order to improve the accuracy of the information obtained from the neighboring nodes when the bypass is generated due to a link failure and the immediacy of the route recovery. Simulation results show that the proposed technique improves the performance in terms of the delay in transmission compared to traditional AODV.

• Journal of KIISE:Information Networking
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• v.27 no.2
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• pp.187-196
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• 2000

Failures in ATM networks can occur at virtual path (VP) links, virtual path switches, and virtual channel (VC) switches. Restoration schemes have been proposed for VP link and VP switch failures, however, none for VC switch failures. In general, VC switches are used for edge nodes in protection domains. Since even only one VC switch failure can cause a critical problem, new restoration schemes for VC switch failures are highly required. Restoration schemes at the VP level proposed so far can be categorized into those using the flooding algorithm and those using the backup virtual path (BVP) concept. Even though the latter cannot handle unpredictable failures, it has some advantages such as fast restoration and low spare capacity requirement. In this paper, we propose new restoration schemes using a new type of BVPs to handle VC switch failures. The simulation results show that the proposed schemes can restore virtual connection failures due to VC switch failures without degrading restorability for VP failures.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1998.10a
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• pp.114-117
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• 1998

Failure to link business or operations strategy with the activities of operations is a critical problem in strategy implementation process. This problem comes from malfunction of a coordination and control mechanism to support the strategic direction by effective communication throughout the firm. A performance measurement and evaluation system (PMES) is thought as a core mechanism to monitor, direct. and induce desirable activities. We have developed a new strategic PMES (SPMES) that can effectively support the manufacturing strategy by utilizing customized performance measures. They are selected from a pool of four distinct but closely related sets of performance measures; financial, market, internal competency, and performance driver. In this paper, we briefly review the structure of the SPMES and explain the change process of PMES into SPMES in manufacturing business units. First we analyze the business environment and manufacturing strategy to identify short- and long-term issues facing the management. Next step is scrutinizing the objectives and activities of every function and process in the business unit. Using the information obtained, we can diagnose the gaps between currently effective PMES and desirable SPMES supporting the strategies. Once the problems in existing system are identified, we reconfigure the existing and new measures to establish a SPMES through a series of analyses, discussions and workshops. In organizing the selected measures in the new system, we use AHP method to reflect the relative importance of the measures in a specific business. Finally, modification or development of information system to support the SPMES wraps up the development process, and implementation begins. We explain the entire process using two cases to clarify the real meanings and the difficulties of PMES change process.

• Journal of KIISE:Information Networking
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• v.37 no.1
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• pp.35-41
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• 2010

Since the ad-hoc network allow nodes to communicate each other without infrastructure system and predefined configuration, it comes into the spotlight that is suitable to ubiquitous society. In ad-hoc network, route recovery mechanism is considered important. Normally route recovery is needed to solve the link failure problem because there is no route maintaining system like a router in ad-hoc networks. In this paper we propose BS-AODV(Bidirectional Searching-AODV) route recovery method. The proposed method is a local repair method that can be applied in all of the network area. Unlike a limited local repair method in AODV. the proposed method adopts the bidirectional searching method where the upstream/downstream nodes can send the route maintenance messages. Restricting the flooding of route request messages, the proposed scheme attempts to minimize the costs of local repair, the performance of the proposed scheme is evaluated through the simulations. In two scenarios which variate the node numbers and node speed, the comparison among the proposed scheme, AODV and AOMDV is shown in terms of the control traffic and data delivery ratio.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.8
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• pp.949-956
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• 1999

이 논문에서는 ATM (Asynchronous Transfer Mode) 방식의 초고속망의 장애 발생 시 이용자 연결의 QoS (Quality of Service)를 고려하여 복구할 수 있게 하는 보호 망 설계 방안을 제시한다. 제시한 설계 방안에 기초한 비용과 복구 특성을 분석과 모의 실험을 통해 알아본다. 제안하는 망에서의 복구는 분리 VP 그룹 (Disjoint Virtual Path Group, DVPG) 을 사용하는 상태 독립적 (State- independent) 방식으로 복구된다. ATM 망의 운용 및 보호 VP 할당과 용량 배정 문제를 정의하고 이를 바탕으로 최소의 비용을 갖는 VP 망을 설계한다. 망의 고장 시 기존 노드간의 VP 연결은 미리 할당된 링크 또는 노드 분리 보호 VP 경로를 따라 간단한 복구 알고리즘에 의해 빠르게 복구된다. QoS의 고려는 추가 비용을 필요로 하지만 정확한 이용자 연결의 복구를 실현하며, 분리 VP 그룹의 적용은 비용을 상승시키지만, 빠른 복구와 복수의 고장에 대처할 수 있는 방안이 된다.Abstract A cost evaluation of protection scheme for VP-based ATM network is presented here and its related characteristics are evaluated. The proposed and evaluated scheme is a state-independent restoration scheme using a disjoint path group. For fast and simple restoration of failed connections, link disjoint or node disjoint VP groups (DVPG) were utilized in this paper. A VP assignment and capacity planning problem is formulated. When failure occurs, the failed working VPs are switched to the protection VPs of disjoint path groups with a simple restoration scheme. And, cost evaluation and restoration characteristics are presented. The consideration of multiple QoS (Quality of Service) levels and disjoint path group protection scheme require additional network cost but acquire fit and fast restoration.

• STI Policy Review
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• v.6 no.2
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• pp.54-86
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• 2015

The study examines the U.S. Small Business Innovation Research (SBIR) program, with a focus on the recent Reauthorization, and compares, in the political context, the U.S. and East Asian countries-Japan, Korea and Taiwan-that adopted the U.S. SBIR program. For the systematic analysis and cross-country comparison, the study employs Kingdon (2003)'s framework-his political theory and Garbage Can Model-to identify political participants and processes underlying the SBIR Reauthorization and to analyze the differences in problem, policy, and politics streams between the U.S. and East Asian countries. For the cross-country comparison, specifically, the study uses various data sources such as OECD, Global Entrepreneurship Monitor, Hofstede's Cultural Dimensions, and World Value Survey. Based on the analysis outcomes, implications of U.S. practices on East Asian countries are extracted as follows. East Asian countries tend to: Have higher entrepreneurial aspiration while lower entrepreneurial activity and attitude than the U.S.; bear higher long term orientation and uncertainty avoidance while lower individualism than the U.S.; and have greater expectations of technology development and higher confidence in political parties while participating less in political action than the U.S. Drawing on the differences, the following policy recommendations are suggested. East Asian countries should: Improve entrepreneurs' access to resources (in particular, financial resource) in order to link their high entrepreneurial aspiration to actual entrepreneurial activities; cultivate failure-tolerating culture and risk-taking entrepreneurs, for instance, by providing a second chance to SBIR-participating businesses that failed to materialize their innovative ideas; and leverage their high expectations of new technology in order to take bold actions regarding their SBIR programs, and update the programs by drawing out constructive dialogues between SBIR stakeholders.

• Journal of The Korean Society of Clinical Toxicology
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• v.9 no.2
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• pp.95-100
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• 2011

Purpose: Ingestion of puffer fish can be poisonous due to the presence of potent neurotoxins such as tetrodotoxin (TTX) found in its tissues. There are few clinical reports related to TTX. We performed this study to evaluate the clinical characteristics of TTX poisoning. Methods: We conducted a retrospective study of the 41 patients diagnosed with TTX poisoning who visited the Seoul Asan medical center from July 2004 and December 2010. A review of patients' electronic medical records and patient telephone interviews were conducted. Diagnosis of TTX poisoning was confirmed by observing the casual link between puffer fish consumption and the development of typical TTX intoxication symptoms. Results: The mean age of the patients included in the study was 46.6 years. The highest incidence of intoxication was observed in patients in their 50s (10 patients). Seasonal distribution of intoxication events included 10 in spring, 7 in summer, 10 in fall, and 14 in winter. In most cases, symptoms occurred within 1 hour of ingestion. A wide range of symptoms were associated with puffer fish ingestion affecting multiple body systems including neuromuscular (27 patients), gastrointestinal (19 patients), and cardiopulmonary/vascular (19 patients). All patients were treated with symptomatic and supportive therapy and recovered completely, without sequelae, within 48 hours. In three cases, ventilator support was required. Conclusion: TTX poisoning is not seasonally related, and patients admitted to the emergency room were observed with a wide range of symptoms. Where TTX poisoning is diagnosed, supportive therapy should be performed. Early intubation and ventilation is important, especially is cases of respiratory failure.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.2 s.48
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• pp.11-19
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• 2006

In this paper the seismic performances of 4, 10, and 30-story staggered truss systems (STS) were evaluated by observing the force-displacement relationship up io failure. The results were compared with the seismic performance of conventional moment resisting frames and braced frames. According to the analysis results, the STS showed relatively satisfactory lateral load resisting capability. However, in the mid- to high-rise STS, plastic hinges formed first at the chords were transferred to vertical members of the vierendeel panels, which formed a week link and subsequently leaded to brittle collapse of the structure. Therefore to enhance the ductility of STS it would be necessary to reinforce the vertical bracing members of the virendeel panels so that the plastic hinges, once toned in cord members of a virendeel panel, spread out to virendeel panels of neighboring stories.