• Spatial Information Research
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• v.9 no.1
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• pp.51-72
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• 2001

It is frequently pointed out that the conventional field survey for natural environment has may limitations in terms of positional accuracy, real-time GIS data acquisition, and economic efficiency. The aim of this research was to develop an on site real-time mapping technique that enables the surveyor to input data in the field. The idea is based upon the recent trends in the field of Telecommunication and Information Technology that uses a GPS, wireless network computing, moving computing, etc. A virtual office approach has been adopted, in which a portable computer is linked to a GPS and field workers record data on the computer at the site and analyse data on site. This field mapping system has shown to be much less susceptible to the positional accuracy than that of th conventional approach. The Graphic User Interface, in particular, were ideally suited to combining positional information with attribute data which changes with every survey points. This interface allows users to interactively display and query GIS layers reproduced from the past survey results. The GIS database stored in the virtual office will serve to carry out a highly reliable survey since it could play a crucial role in identifying temporal and spatial changes occurred in the site. It is expected that integrated utilization of field data among the related agencies would be increased much more than before since the virtual office survey would be a powerful tool to ensure geometric fidelity in GIS database creation process. This paper also discusses the limitations and future direction of the present prototype research.

• Journal of Internet Computing and Services
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• v.14 no.6
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• pp.117-124
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• 2013

In this paper, we present a new method which efficiently estimates a face direction from a sequences of input video images in real time fashion. For this work, the proposed method performs detecting the facial region and major facial features such as both eyes, nose and mouth by using the Haar-like feature, which is relatively not sensitive against light variation, from the detected facial area. Then, it becomes able to track the feature points from every frame using optical flow in real time fashion, and determine the direction of the face based on the feature points tracked. Further, in order to prevent the erroneously recognizing the false positions of the facial features when if the coordinates of the features are lost during the tracking by using optical flow, the proposed method determines the validity of locations of the facial features using the template matching of detected facial features in real time. Depending on the correlation rate of re-considering the detection of the features by the template matching, the face direction estimation process is divided into detecting the facial features again or tracking features while determining the direction of the face. The template matching initially saves the location information of 4 facial features such as the left and right eye, the end of nose and mouse in facial feature detection phase and reevaluated these information when the similarity measure between the stored information and the traced facial information by optical flow is exceed a certain level of threshold by detecting the new facial features from the input image. The proposed approach automatically combines the phase of detecting facial features and the phase of tracking features reciprocally and enables to estimate face pose stably in a real-time fashion. From the experiment, we can prove that the proposed method efficiently estimates face direction.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.2
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• pp.525-531
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• 2015

According to the increasing demand for 3D indoor spatial information, the utilization of a terrestrial laser scanner comes to the fore. However, the research for the comparison between a terrestrial laser scanning method and a traditional surveying method is insufficient. The paper evaluated the time-efficiency and the locational accuracy of an AMCW type and a direct TOF type of terrestrial laser scanning methods in comparison with the observation using a total station. As a result, an AMCW type showed higher time-efficiency than a direct TOF type and the RMSE between the two types of data was ${\pm}1mm$. Moreover, the terrestrial laser scanning method showed twice higher time-efficiency than the observation using a total station and the RMSE between the two data was ${\pm}3.4cm$. The results indicate that the terrestrial laser scanning method has better profitability and performance for 3D indoor modeling than the traditional survey using a total station. In the future, a terrestrial laser scanner can be efficiently utilized in the construction of 3D indoor spatial information.

• Journal of Korea Spatial Information System Society
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• v.2 no.2 s.4
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• pp.25-37
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• 2000

As computer systems of high capacity and high performance recently emerged, various researches about GISs(Geographic Information Systems) have been in progress and many GIS applications have also been developed. From the domestic situation where many people are using mobile devices, because of the recent advances in the mobile technology, we can infer that the time will come when every individual will carry a mobile device with a GPS(Global Positioning System) module resulting from the development of a miniature GPS Module. Therefore, a mobile GIS that can allows users to deal with dynamic GIS data management and perform their tasks while moving will be required. This paper discusses the design and implementation of a mobile GIS using the shareware DBMS, called postgresSQL. The Mobile GIS in which a mobile concept is utilized at the GIS data server makes it possible to insert, delete, update GIS data, to zoom in and zoom out displayed maps, and to locate the user's position on the client device. Therefore, It is possible to manage dynamic GIS data in order to deal with GIS data on the maps while moving, connect various GIS data servers through the middleware, and connected with ITS (Intelligent Transport System) which is one of applications of the Mobile GIS developed in this paper.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.197-201
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• 2008

Conceptual cost estimates for domestic highway projects have generally been conducted using governmental unit-price references. Inaccuracies in governmental unit-price data has repeatedly addressed in the Korean construction industry which often lead to poor decision making and cost management practices. Thus, needs for developing a better way of conceptual cost estimating has been widely recognized. This research is considered as the first step in developing such model using real-world cost data based on actual construction activities. The data analyzed in this paper includes 41 P.S.C (Prestressed Concrete) Box bridges which broke into 4 categories based on construction methods such as I.L.M(Incremental Launching Method), M.S.S(Movable Scaffolding System), F.S.M(Full Staging Method), and F.C.M(Free Cantilever Method). Actual design documents; including actual cost estimating documents, drawings and specifications were carefully reviewed to effectively break down cost structures for PSC girder bridges. Among more than 40 cost categories for each P.S.C girder bridge type, 7 of them were identified which accounted for more than 95% of total construction cost (ILM: 99.47%, MSS: 99.22%, FSM: 98.18%, and FCM: 98.12%). In order to validate the clustering of cost categories, the variation of each cost category has been investigated which resulted in between -1.16 % and 0.59%.

• The KIPS Transactions:PartD
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• v.16D no.3
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• pp.451-462
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• 2009

Collaborative Filtering (CF), one of the most successful technologies among recommender systems, is a system assisting users in easily finding the useful information. However, despite its success and popularity, CF encounters a serious limitation with quality evaluation, called cold start problems. To alleviate this limitation, in this paper, we propose a unique method of building models derived from explicit ratings and applying the models to CF recommender systems. The proposed method is divided into two phases, an offline phase and an online phase. First, the offline phase is a building pre-computed model phase in which most of tasks can be conducted. Second, the online phase is either a prediction or recommendation phase in which the models are used. In a model building phase, we first determine a priori predicted rating and subsequently identify prediction errors for each user. From this error information, an error-reflected model is constructed. The error-reflected model, which is reflected average prior prediction errors of user neighbors and item neighbors, can make accurate predictions in the situation where users or items have few opinions; this is known as the cold start problems. In addition, in order to reduce the re-building tasks, the error-reflected model is designed such that the model is updated effectively and users'new opinions are reflected incrementally, even when users present a new rating feedback.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.901-908
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• 2011

For the available grid environmental realization, the resource supply PC must have to provide an appropriate security function of their operation environments. SKY@HOME is a kind of the grid computing environments. If this has not supervised by administrator handling smoothly, it is inherently vulnerable state to the security level of the grid environments, because the resource supply PC is not update a security function without delay. It is also have the troublesome problems which have to install of an additional security program for support the appropriate security. This paper proposes an integration security model on the policy-based that provides an update each level according to the situation of the resource supply PC for improving its problems as a security aspect of the SKY@HOME. This model analyzes the security state of the resource supply PC respectively, and then the result is available to provide an appropriate security of the resource supply PC using an integration security model. The proposed model is not need additionally to buy and install the software, because it is provided the security management server oriented service. It is also able to set up the suit security function of a characteristic of the each resource supply PC. As a result, this paper clearly show the participation of resource supply PC improved about 20%.

• Journal of KIISE:Information Networking
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• v.30 no.4
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• pp.474-483
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• 2003

The secret sharing is the basic concept of the threshold cryptosystem and has an important position in the modern cryptography. At 1995, Jarecki proposed the proactive secret sharing to be a solution of existing the mobile adversary and also proposed the share renewal scheme for (k, n) threshold scheme. For n participants in the protocol, his method needs O($n^2$) modular exponentiation per one participant. It is very high computational cost and is not fit for the scalable cryptosystem. In this paper, we propose the efficient share renewal scheme that need only O(n) modular exponentiation per participant. And we prove our scheme is secure if less that ${\frac}\frac{1}{2}n-1$ adversaries exist and they static adversary.

• The Transactions of the Korea Information Processing Society
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• v.7 no.11S
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• pp.3702-3713
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• 2000

Telecommunications standards have two different types of regulations: one is a law. enacted by government which all telecommunications related industries must observe. The other is a recommendatory standards. formulated by either government agency or some standardization organizations. Observation of these standards is not obligatory. However, technical standards are strict laws and ordinances based on common judgement and various conditions for evaluation of levels and limits. This paper deals with enhancing productivity of enactment and revision of technical standards. Through database of above related information we secure information continuity and public property of cyber space for the public. In this paper. we also classify recent data within the website in and out of the country offering four different methods of information retrieval and management system. The four retrieval methods suggested in this paper are itemized keyword retrieval. hierarchical retrieval, regulatory keyword retrieval and chronological keyword retrieval. These various retrieval methods provide the public with information of enactment and amendment of laws and regulations in the cyber space. thereby guarantees the sharing of information. Finally the important feature of the information retrieval system implemented in this paper is the online updating capability of law and regulations through the internet.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.74-74
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• 2016

복잡한 지형에서 컴퓨터를 이용한 물리적 기반 수치모의는 합리적인 시간내에 연산을 완료하기 위해 대개 큰 연산장비 들을 요구한다. 더욱이 모의되는 현상이 시간단계마다 갱신되어지는 동역학적 현상에 기반된 비정상상태일 때 연산성능은 고려되어지는 가장 중요한 주제가 될 수 있다. 연산 시간을 줄이기 위한 가장 널리 이용되는 전략중의 하나는 적절한 수의 프로세서를 이용하는 병렬 기법이다. 최근 들어 연산속도를 가속화하기 위해 다수의 코어를 이용한 OpenMP 와 MPI 기법들이 병렬해석기법으로 대두되었고 그래픽 연산장치를 이용한 병렬처리 해석기법도 소개되고 있다. 본 연구에서는 중앙연산장치를 이용한 병렬 해석기법을 이용하여 제내지 침수해석의 적용성을 검토하고 그 결과을 비교하였다. 본 연구를 위해 OpenMP 병렬기법을 이용하여 확산파 침수해석 프로그램의 원시코드를 재작성하여 가상 및 실제 유역에 적용하였다. 해석결과는 분산메모리 병렬해석 기법인 MPI를 도입한 모형의 결과와 비교되었다. OpenMP를 도입한 모형과 MPI를 도입한 경우 유량 및 수심의 경우 오차 허용 한계내에 수렴되어 만족되었으나 그러나 연산 속도의 경우 두 기법간의 자료의 저장 방법 차이로 인해 차이를 나타내었다. 가상 유역에 적용된 결과로 검토된 각 기법의 증속(speedup) 효과는 MPI의 경우 4 코어를 이용하였을 때 최고 2.62 배 정도에 도달하는 것으로 나타났다. OpenMP 를 적용한 경우 2.87 배 정도로 나타나 OpenMP 를 이용하였을 때 증속효과가 조금 더 뛰어났다. 이는 두 기법의 메모리 저장방식의 차이로 인해 자료의 전송량과 전송 시간이 적은 OpenMP 를 도입한 모형에서 MPI 모형 보다 상대적으로 뛰어난 결과를 나타내었다. 실제 유역의 적용을 위해 상대적으로 우수한 증속결과를 나타낸 OpenMP를 도입한 모형을 Malpasset 댐 붕괴 유역에 적용하였다. 적용된 요소의 수는 각각 45254, 11352 개로 비교적 많은 요소를 가진 하류지역에 적용하여 병렬효과를 극대화하고자 하였다. 적용결과 두 경우 모두 병렬 해석 기법을 도입한 모형에서 유속과 침수심 등은 순차적 모형과 동일한 값을 나타내었으나 증속효과로 인한 연산시간은 순차적 모형에서 8.57 배로 나타나 병렬 모형의 상대적으로 빠른 연산속도를 판단할 있었다. 위의 적용결과를 통해 계산 요소들이 많은 2 차원 해석의 경우 기존의 단일 코어를 이용한 순차적 해석은 장시간에 걸치 연산시간으로 인해 작업효율이 낮아지는 결과를 발생시킬 수 있으며 병렬 해석을 도입할 경우 주어진 컴퓨터 자원를 효율적으로 이용가능하여 합리적인 연산시간으로 연산결과를 얻는 것이 가능하여 반복적 통계 기법/Ensemble 해석 등을 이용한 종합적 해석이 좀 더 실용적으로 이루어 질 수 있을 것이라고 판단되었다.