• Journal of The Korean Association For Science Education
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• v.32 no.5
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• pp.823-840
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• 2012

The importance of teaching the nature of science (NOS) has been emphasized in the science curriculum, especially in the science curriculum for science-gifted students. Nevertheless, few studies concerning the structure and formation of students' mental model on NOS have been carried out. This study aimed to explore science-gifted students' understanding of 'fact', 'hypothesis', 'theory', 'law', and 'scientificness' by utilizing semantic network analysis. One hundred ten science-gifted middle school students who were selected by a national university participated in this study. We collected students' written responses of five items and analyzed them by the semantic network analysis(SNA) method. As a result, the core ideas of students' understanding of 'fact' were proof and reality, of 'hypothesis' were tentativeness and uncertainty, of 'theory' was proven hypothesis by experimentation, of 'law' were absoluteness and authority, and of 'scientificness' were factual evidence, verifiability, accurate and logical theoretical framework. The result of integrated semantic network illustrated that the viewpoint of science-gifted students were similar to absolutism and logical positivism (empiricism). Methodologically, this study showed that the semantic network analysis method was an useful tool for visualization of students' mental model of scientific conceptions including NOS.

• International Commerce and Information Review
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• v.19 no.4
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• pp.29-50
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• 2017

In emerging technologies, innovation processes are dynamic in that the government needs to regularly review its policies to resonate with rapid technological advancements, changing public needs, and evolving global trends. In the 1990s, the Internet grew at an explosive rate, but many applications were constrained due to security concerns. Public Key Infrastructure (PKI) seemed to be the fundamental technology to address these concerns by providing security functions. As of 2017, PKI is still one of the best technologies for electronic authentication in an open network, but it is used only in limited areas: for user authentications in closed networks and for server authentications within network security infrastructure like SSL/TLS. The difference between expectation and reality of PKI usage is due to the evolution of the Internet along with the global adoption of new authentication policies under the Internet governance in the early 2000s. The new Internet governance based on the cooperation between multi-stakeholders is changing the way in which a government should act with regard to its technological policies. This paper analyzes different PKI policy approaches in the United States and Korea from the perspective of path-dependence theory. Their different policy results show evidence of the rise of the Internet governance, and may have important implications for policy-makers in the current global Internet society.

• The KIPS Transactions:PartD
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• v.11D no.4
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• pp.937-950
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• 2004

With growing population of internet and web applications, distributed environment is considered to be the standard architecture of application. A network management systems(NMS) is necessary to control and monitor the complex network resources for providing and sharing the heft quality service. We recognize the NMS as a standard infrastructure for supporting efficient networking and a separate commercial applications. We believe every resource including software, hardware and environment for the network management should be separated from special protocols, vendors and applications. Therefore, We need a standard network management system that is efficient and consistent because of the heterogeous network features. In regards to software development, software reuse through assembling and extending the reusable elements such as patterns and components assures to realize the best productivity and quality The component based development(CBD) methodology that can assemble black box though well defined interfaces makes it possible to develop easer and quicker applications and is proved as the best software development solution involved in construction, selection and assembly of components. In this thesis, we describe the architecture for the network management and identify, define and design the components through analysis and design in the network management domain and Identified components mapped to the component architecture. We also specify the component development and design and implement the component for developing the network management. Implemented components apply to the component repository system that register, retrieve and understand the components. We analyze, design and implement the entire network management system based on configuration, connection, performance and fault management through the pre-developed components.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12B
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• pp.1380-1386
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• 2009

In this paper, we propose a CQS(Calendar Queue Scheduler) architecture which was designed for processing multimedia and timing traffic in home network. With various characteristics of the increased traffic flowed in home such as VoIP, VOD, IPTV, and Best-efforts traffic, the needs of managing QoS(Quality of Service) are being discussed. Making a group regarding application or service is effective to guarantee successful QoS under the restricted circumstances. The proposed design is aimed for home gateway corresponding to the end points of receiver on end-to-end QoS and eligible for supporting multimedia traffic within restricted network sources and optimizing queue sizes. Then, we simulated the area for each module and each memory. The area for each module is referenced by NAND($2{\times}1$) Gate(11.09) when synthesizing with Magnachip 0.18 CMOS libraries through the Synopsys Design Compiler. We verified the portion of memory is 85.38% of the entire CQS. And each memory size is extracted through CACTI 5.3(a unit in mm2). According to the increase of the memory’sentry, the increment of memory area gradually increases, and defining the day size for 1 year definitely affects the total CQS area. In this paper, we discussed design methodology and operation for each module when designing CQS by hardware.

• Journal of The Korean Association For Science Education
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• v.35 no.6
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• pp.997-1006
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• 2015

Perception of the experiment is one of the most important factors of students' understanding of scientific inquiry and the nature of science. This study examined the perception of middle and high school students of the meaning of 'experiment' in the biological sciences. Semantic network analysis (SNA) was especially used to visualize students' perception structure in this study. One hundred and ninety middle school students and 200 high school students participated in this study. Students responded to two questions on the meaning of 'experiment' in science and biology. This study constructed four semantic networks based on the collected response. As a result, middle school students about the 'experiment' in science are 'we', 'direct', 'principle' of such words was aware of the experiments from the center to the active side. The high school students' 'theory', 'true', 'information' were recognized as an experiment that explores the process of creating a knowledge center including the word. In addition, middle school students relative to 'experiment' of the creature around the 'dissection', 'body', high school students were recognized as 'life', 'observation' observation activities dealing with the living organisms and recognized as a core. The results of this study will be used as important evidence in the future to map out an experiment in biological science curriculum.

• Journal of the Economic Geographical Society of Korea
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• v.13 no.3
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• pp.335-353
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• 2010

Following the emergence of a knowledge-based economy, the triple helix model has been recognized as a new - regional and national - innovation model. This model seeks to understand the innovation process that is centered upon the university-industry-government interactions. The governance of the triple helix innovation system can be divided into three models according to the structure and depth of university-industry-government interactions. In the context of evolution, the triple helix can be established through the following three processes of development; i) internal transformation of each helix, ii) impacts of one helix on another helix, and iii) horizontal interactions among three helices. In theory, the triple helix model can be covered as part of the innovation system perspective. Compared to the innovation system perspective, the triple helix model tends to pay, however, more attention to the incompleteness of innovation system and the role of university in the process of knowledge creation. In view of regional innovation, the triple helix can be sustained when the triple helix spaces, including knowledge space, consensus space and innovation space, are created and the three triple helix spaces interact with one another. The existing literature on the triple helix model tends to make selectively use of only a single method between the qualitative method and the quantitative method, although both have shortcomings to reveal the dynamic characteristics of university-industry-government relations. Therefore, research on the triple helix is required to reconcile with two research methods, which are distinct but complementary in nature.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.6
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• pp.1-16
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• 2012

In this paper, we propose a cost-effective location and service management scheme in LTE (Long Term Evolution) networks, which a per-user service proxy is created to serve as a gateway between the mobile user and all client-server applications engaged by the mobile user. The service proxy is always co-located with the mobile user's location database such that whenever the MU's location database moves during a location hand-off, a service hand-off also ensues to co-locate the service proxy with the location database. This allows the proxy to know the location of the mobile user all the time to reduce the network communication cost for service delivery. We analyze four integrated location and service management schemes. Our results show that the centralized scheme performs the best when the mobile user's SMR (service to mobility ratio) is low and ${\upsilon}$(session to mobility ratio) is high, while the fully distributed scheme performs the best when both SMR and ${\upsilon}$ are high. In all other conditions, the dynamic anchor scheme is the best except when the service context transfer cost is high under which the static anchor scheme performs the best. Through analytical results, we demonstrate that different users with vastly different mobility and service patterns should adopt different integrated location and service management methods to optimize system performance.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.6
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• pp.257-264
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• 2012

In this paper, we propose a Route Stability-based Direction Guided Routing protocol(RSDGR) in mobile ad-hoc wireless networks. The main features and contributions of the proposed routing protocol are as follows. First, it can calculate link stability between two nodes as well as route stability of multi hop quantitatively by using nodes' mobility. And this protocol can establish the most stable path between a source node and a destination node. Second, according to the route stability between a source node and a destination node, it can control and optimize the direction guided region dynamically for route setup. Third, we suggest theoretical model for quantitative calculation of link stability between two nodes and route stability of multi hop path. The performance evaluation of the proposed routing protocol is performed by simulation using OPNET(Optimized Network Engineering Tool) and theoretical analysis. The results of performance evaluation show that the patterns of PDR are similar in simulation and analysis according to route stability. The faster mobile nodes' velocity and the smaller source node's direct guided reigion, the lower route stability and PDR and the higher delay and control overhead related to this.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.10a
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• pp.444-449
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• 1995

한국형 표준 원자력발전소의 정지냉각운전시 최대냉각율은 75$^{\circ}$F/hr(41.7$^{\circ}C$/hr)로 기술사양서에 규정되어 있다. 정지냉각운전 냉각율에 가장 큰 영향을 미치는 2가지 중요한 변수는 정지냉각계통 열교환기를 지나는 원자로냉각재 유량과 기기냉각수의 온도다. 이중 열교환기를 지나는 원자로냉각재 유량은 butterfly형 정지냉각계통 유량조절밸브의 개도에 의하여 조절되는데 개도에 따른 throttle 능력이 중요한 인자다. 또 기기냉각수의 온도는 해수온도의 변화에 따라 편차가 발생하므로 유량조절밸브의 개도와 기기냉각수 온도의 상관관계에 따라 냉각능력이 달라진다. 본 논문에서는 현 울진 3&4호기 정지냉각계통 열 교환기 및 조절밸브 둥의 설비를 기준으로 기술사양서 상의 냉각율 75$^{\circ}$F/hr(41.7$^{\circ}C$/hr) 유지가 가능한 최저 기기냉각수의 온도를 찾아보았고, 아울러 기기냉각수의 온도와 조절밸브의 개도 사이의 관계를 조사하였다. 그 결과 현재의 울진 3&4호기 조절밸브를 최저개도로 조절할 때 약 57$^{\circ}$F(13.9$^{\circ}C$)의 기기냉각수가 공급되어도 냉각율 제한치를 넘지 않는 것으로 분석되었다. 한편, 최저조절가능 유량이 약 2000 gpm(7570 l/min)일 경우에는 낮은 기기냉각수가 공급될 경우 최대냉각율을 초과하므로 한 train을 정지시키고 한 train만으로 운전할 것을 고려하여야 할 것으로 보인다. 이 경우 최저 약 56.5$^{\circ}$F(13.6$^{\circ}C$)의 기기냉각수가 공급되어야 한다. 본 논문의 분석결과는 향후 기기설계사양서나 운전지침서 등에 반영되어 실제 발전소 설계 및 운전절차 수립에 기여할 수 있을 것으로 생각된다.공감대의 형성이 요구된다. 질적 측면에서는 공원 녹지의 기능성의 회복이라는 측면과 시대에 부합되는 새로운 기능 및 가치의 부여가 필요하며, 이를 위해서는 공원의 매력, 공원의 시설기능 증진, 녹지의 질의 향상 및 녹지 가치의 증진에 대한 다양한 시책이 요구된다. 구성적 측면에서는 공원녹지의 개별적 존재보다는 공원 녹지를 상호간 유기적인 계통을 확보하여 공원 녹지의 네트워크를 형성하여 도시 속의 산재된 고립된 섬으로서의 공원 녹지가 아닌 시민생활에 늘 가까이 있는 생활 속의 공원녹지로 재편되어야 한다. 이러한 정책의 의제는 양적 측면에서 보전(CONSERVATION)과 창출(CREATION), 질적 측면에서 쇄신(RENOVATION)과 복구(RESTORATION), 그리고 구성적 측면에서 공원 녹지의 연결(CONNECTION)과 시민 참여에 의한 운동(MOVEMENT)이라는 정책 개념의 구현을 통해 가능하다. 이러한 정책 개념과 의제를 가지고 서울시 공원 녹지 정책을 구체화시키기 위해서 푸르름의 새로운 탄생이라는 기치 아래 풍요로운 서울, 사랑 받는 공원, 생활 속의 녹지의 3대 목표, 공원 녹지의 보전, 잠재 공원 녹지의 창출, 공원의 활성화, 녹지의 복구, 경관 보전 및 복구, 공원 녹지의 네트워크, 도시 녹화의 7대 과제를 설정하고 미시설 공원 녹지 집행, 개발 사업시 공원 녹지의 확보, 환경 녹지의 총량 보호 관리, 도시 소공원 개발, 역사 문화 공원 조성, 하천 공간 복원, 공원 시설 기능 개선, 이용 프로그램 개발, 공원 관리 개선, 환경 피해 녹지의 회복, 도시 환경 림 조성, 녹지 기능 증진, 도시 자연 경관 보전, 공원 녹지체계 구성, 공원 녹지 공급 균형, 주변 환경 녹화, 가로 녹화의 17개 시책을 제안하였다. 이러한 정책사업의 원활한 추진을 위해서는 기존의 관주도의 일방적인 공원 녹지 행정이 아닌 시민의 참여를 통한 시민이 함께 하는 정 책 사업의 추진이 요구되며, 특히 민간 부문의

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.11
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• pp.1170-1181
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• 2012

Wireless Sensor Networks(WSNs) are used in diverse applications. In general, sensor nodes that are easily deployed on specific areas have many resource constrains such as battery power, memory sizes, MCUs, RFs and so on. Hence, first of all, the efficient energy consumption is strongly required in WSNs. In terms of event states, event-driven deliverly model (i.e. surveillance and reconnaissance applications) has several characteristics. On the basis of such a model, clustering algorithms can be mostly used to manage sensor nodes' energy efficiently owing to the advantages of data aggregations. Since a specific node collects packets from its child nodes in a network topology and aggregates them into one packet to relay them once, amount of transmitted packets to a sink node can be reduced. However, most clustering algorithms have been designed without considering can be reduced. However, most clustering algorithms have been designed without considering characteristics of event-driven deliverly model, which results in some problems. In this paper, we propose enhanced clustering algorithms regarding with both targets' movement and energy efficiency in order for applications of surveillance and reconnaissance. These algorithms form some clusters to contend locally between nodes, which have already detected certain targets, by using a method which called CHEW (Cluster Head Election Window). Therefore, our proposed algorithms enable to reduce not only the cost of cluster maintenance, but also energy consumption. In conclusion, we analyze traces of the clusters' movements according to targets' locations, evaluate the traces' results and we compare our algorithms with others through simulations. Finally, we verify our algorithms use power energy efficiently.