• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.222-222
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• 2023

오픈 소스 유체역학 소프트웨어인 OpenFOAM은 다양한 유체 흐름에 적용 가능한 프로그램들로 구성되어 있다. 이 중 interFoam은 밀도가 다른 두 유체(i.e., 물, 공기) 간의 경계를 추적하는 기법을 기반으로 한 프로그램으로, 파랑의 거동 모의에 주로 쓰이고 있다. 파생형 프로그램으로는 동격자(dynamic mesh) 및 중첩 격자 기법(overset grid method)을 interFoam에 추가한 overInterDyMFoam이 있다. 두 기법을 사용하면 각각 여러 영역에서 유체흐름과 다중 물체 간의 상호작용을 효율적으로 모의할 수 있다. 본 연구에서는 overInterDyMFoam을 사용하여 두 개 수문의 개방 움직임을 구현하고 생성된 파랑이 포말대(swash zone)에 접근하였을 때의 흐름 특성을 조사하였다. 수치모형실험 결과 수문 개방 속도가 댐 붕괴 파랑 흐름 전파속도에 영향을 미치는 사실을 발견하였다. 또한, 처오름과 처내림의 상호작용에 의한 난류 운동 특성을 조사하기 위해 수문 개방시간 간격을 0초~3초로 설정하였다. 수치모형실험 결과는 수리모형실험의 수면 변동 시계열과 속도 시계열 결과와 비교하여 모형의 정확성이 검증되었다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.779-782
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• 2017

OpenBR is a framework for researching new facial recognition methods, improving existing algorithms, interacting with commercial systems, measuring perceived performance, and deploying automated biometric systems. Designed to facilitate rapid algorithm prototyping, it features a mature core framework, flexible plug-in system, and open and closed source development support. The established algorithms can be used for specific forms such as face recognition, age estimation, and gender estimation. In this paper, we describe the framework of OpenBR and implement facial recognition, gender estimation, and age estimation using supported programs.

• Spatial Information Research
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• v.23 no.5
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• pp.41-52
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• 2015

MOLIT (Minister of Land, Infrastructure and Transport) authorized Indoor Spatial Information as Basic spatial information in 2013. It became a legal evidence for constructing and managing Indoor Spatial Information. Although it has a little advantage to utilize as service level that Indoor Spatial Information by laser scan or measurement, it has a lot of problems such as consuming many resources, requiring additional progresses for inputting Object Information. In conclusion, it is inefficient to utilize for the maintenance and domestic AEC/FM field. The purposes of this study is to output Indoor Spatial Information by operating IFC model which based on open BIM and to improve availability of Indoor Spatial Information with data visualization. The open-sources of IFC Exporter, a inner program of Revit (Autodesk Inc), is used to output Indoor Spatial Information. Directs 3D Library is also operated to visualize Indoor Spatial Information. It is possible to inter-operate between XML format and the objects of Indoor Spatial Information. It can be utilized in various field as well. For example COBie linkage in facility management, construction of geo-database using air-photogrammetry of UAV (Unmaned Areal Vehicle), the simulation of large-scale military operations and the simulation of large-scale evacuation. The method that is purposed in this study has outstanding advantages such as conformance with national spatial information policy, high level of interoperability as indoor spatial information objects based on IFC, convenience of editing information, light level of data and simplifying progress of producing information.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.1
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• pp.65-71
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• 2016

In recent years, 3D printing has received increasing attention due to releases of low-cost 3D printers based on open-source platform. 3D printing is expected to reduce the barrier to entry in the traditional manufacturing processes by increasing flexibility and creating an advantage to manufacture customized products at low costs. In this study, a unique eyeglass frame was designed to have a snake shape, which has an asymmetric geometry unlike traditional frames. The eyeglass frame was designed in a customized manner by reflecting dimensional characteristics of a customer's face. Finite element analysis was performed to investigate the structural safety of the 3D printed frames during the assembly process. The analysis also considered the effect of anisotropic material properties as determined by tensile tests. The eyeglass frame was then printed using the customized sizes and the best building process. The eyeglass frame was successfully assembled with lenses and without structural failure during its assembly procedure.

• Journal of Technology Innovation
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• v.21 no.1
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• pp.109-139
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• 2013

The objective of this study attempt to examine the prospect whether conventional catch-up theory is also applicable to knowledge intensive industry like Open Source Software(OSS), and the implication from this study can be working as a stepping stone for followers. To do this, we conducted Korean SW firm's interview, and examined U.S. firm's archivings and second source of informations by means of empirical study. We use the inflection point of paradigm shift and difference of technology regime as a framework for empirical study of catch-up process between U.S. and Korean OSS firms. We find that conventional catch-up theory is no more applicable to explain OSS firm's catch-up processes. We also identified the elements that will accelerate the catch-up processes more effectively from the comparison of technology regime between U.S. and Korean OSS firms. As a result, we diagnose the limitation of conventional catch-up theory and discuss the new technology regime which will, ironically, promote the catch-up processes from the condition of low appropriation.

• Journal of Korea Spatial Information System Society
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• v.1 no.2 s.2
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• pp.33-46
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• 1999

In distributed computing platforms like CORBA, wrappers are used to integrate heterogeneous systems or databases. A spatial data provider is one of the wrappers because it provides clients with uniform access interfaces to diverse data sources. The individual implementation of spatial data providers for each of different data sources is not efficient because of redundant coding of the wrapper modules. This paper presents a new architecture of the spatial data provider which consists of two layered objects : independent wrapper components and dependent wrapper components. Independent wrapper components would be reused for implementing a new data provider for a new data source, which dependent wrapper components should be newly coded for every data source. This paper furthermore discussed the issues of implementing the representation of query results in the middleware. There are two methods of keeping query results in the middleware. One is to keep query results as non-CORBA objects and the other is to transform query results into CORBA objects. The evaluation of the above two methods shows that the cost of making CORBA objects is very expensive.

• KIPS Transactions on Software and Data Engineering
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• v.4 no.1
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• pp.1-8
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• 2015

Safety critical systems require exhaustive verification of safety properties, because even a single corner-case fault can cause a critical safety failure. However, existing verification approaches are too costly in terms of time and computational resource required, making it hard to be applied in practice. In this paper, we implemented a tool for minimizing the size of the verification target w.r.t. verification properties to check, based on program slicing technique[1]. The efficacy of program slicing using our tool is demonstrated in a case study with a verification target Trampoline[3], which is an open source automotive operating system compliant with OSEK/VDX[2]. Experiments have shown enhanced performance in verification, with a 71% reduction in the size of the code.

• The Journal of Information Systems
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• v.29 no.2
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• pp.149-171
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• 2020

Purpose With the advent of the 4th Industrial Revolution, related technologies such as IoT, big data, and artificial intelligence technologies are developing through not only specific companies but also a number of unspecified developers called open collaboration. For this reason, it is important to understand the nature of the collaboration that leads to successful open collaboration. Design/methodology/approach We focused the relationship between the collaboration characteristics and collaboration performance of developers who participating in open source software development, which is a representative open collaboration. Specifically, we create the country-specific network and draw the individual developers characteristics from the network such as collaboration scope and collaboration intensity. We compare and analyze the characteristics of developers across countries and explore whether there are differences between indicators. We develop a Web crawler for GitHub, a representative OSSD development site, and collected data of developers who located at China, Japan, Korea, the United States, and Canada. Findings China showed the characteristics of cooperation suitable for the form of weak tie theory, and consistent results were not drawn from other countries. This study confirmed the necessity of exploratory research on collaboration characteristics by country considering that there are differences in open collaboration characteristics or software development environments by country.

• The Journal of Information Systems
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• v.28 no.1
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• pp.73-96
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• 2019

Purpose The purpose of this study is to examine the effect of communication-structure characteristics on performance in online collaboration using the data from Github, one of representative open source software development platforms. We analyze the impact of in-degree/out-degree centralization and reciprocity of communication network on collaboration performance in each project. In addition, we investigate the moderating effect of owner types, an individual developer or an organization. Design/methodology/approach We collect the data of 838 Github projects, and conduct social network analysis for measuring in-degree/out-degree centralization and reciprocity as independent variables. With these variables, hierarchical regression analysis is employed on the relationship between the characteristics of communication structure and collaborative performance. Findings Our results show that for the project owned by an organization, the centralized structure of communication is not associated with the collaboration performance. In addition, the reciprocity is positively related to the collaboration performance. On the other hand, for the project owned by an individual developer, the centralized structure of communication is positively related to the performance, and the reciprocity does not show the positive relationship on the performance.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11b
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• pp.1167-1170
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• 2002

멀티캐스트 기술은 다자간 비디오회의, 대화형 원격 강의, 소프트웨어 배포, 인터넷 게임 등 특정 사용자 그룹에게만 전송하는 효율적인 통신기술이다. 그러나, 멀티캐스트의 개방적 특성상, 언제 어디서나 임의의 그룹멤버가 메시지를 보낼 수 있다. 따라서 부적절한 데이터의 수신으로부터 그룹 멤버들을 보호하고 다양한 DOS 공격으로부터 멀티캐스트 트리를 보호하기 위해 송신자 접근통제를 수행하는 것이 중요하나 소스기반과 단일지점 또는 랑데부 지점에서 인가되거나 인증되는 연구가 진행되어 왔다. 본 논문에서는 접근권한에 따라 전송 메시지가 라우터의 임의의 지점에서 사진에 통제될 수 있는 양방향 멀티캐스트 트리에 대한 다단계 송신자 접근통제 메커니즘을 제시한다 다음으로 제시한 방식과 기존 전송 방식간의 메시지 전송 효율성 측면을 실험을 통하여 분석한다. 제안 방식이 라우터상에서 접근권한의 비교를 통하여 메시지를 사전에 걸러냄으로써 상대적으로 작은 메시지 전달 오버헤드를 갖는 것을 확인하였다.