• Journal of Bio-Environment Control
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• v.12 no.2
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• pp.57-62
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• 2003

In this study, a robotic manipulator for harvesting cucumber was developed. The objective of this research was to design and to construct a robotic manipulator specifically tailored to harvest cucumber in the greenhouse. The system was consisted of an integrated end-efffctor, an image processing system and a controlling system. Especially, the image processing system detected the quality of cucumber within each plant in order for the computer to furnish harvest instructions to the manipulator. In all tests of cucumber, the success rate for cucumber harvest was 84％ in the greenhouse. End-effector, image processing system and controlling system showed good performance. Based on the results of this research the following recommendations are made for further study. Besides harvesting cucumbers, the oldest leaves, creepers and the youngest small side leaves need to be removed.

• Tunnel and Underground Space
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• v.27 no.5
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• pp.303-311
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• 2017

The correlation analysis between the results obtained from DFN flow model and equivalent continuum flow model were conducted on total of 72 DFN blocks having various fracture geometry and domain size. A strong linear relation seems to exist between the two approaches under condition that normalized relative error for continuum behavior (ER) is less than 0.2, and the results from both methods are found to almost identical. To explore the field applicability of equivalent continuum flow model in DFN media, a total of 48 numerical schemes related to inflow of underground circular openings were implemented under various DFN configurations. The equivalent continuum flow model in DFN media with a constant hydraulic aperture was evaluated as valid. However, as the anisotropy increases due to variation of the hydraulic aperture, the results are likely to be overestimated compare to the DFN flow model.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.37 no.6
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• pp.48-59
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• 2000

Eigendecomposition based direction-of-arrival(DOA) estimation algorithm such as MUSIC(multiple signal classification) is known to perform well and provide high resolution in white noise environment. However, its performance degrades severely when the noise process is not white. In this paper we consider the DOA estimation problem in a colored noise environment as a problem of extracting periodic signals from noise, and we take the problem to the wavelet domain. Covariance matrix of multiscale components which are obtained by taking wavelet decomposition on the noise has a special structure which can be approximated with a banded sparse matrix. Compared with noise the correlation between multiscale components of narrowband signal decays slowly, hence the covariance matrix does not have a banded structure. Based on this fact we propose a DOA estimation algorithm that transforms the covariance matrix into wavelet domain and removes noise components located in specific bands. Simulations have been carried out to analyze the proposed algorithm in colored noise processes with various correlation properties.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.11a
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• pp.408-411
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• 2006

신체활동을 위한 공원녹지의 활성화 방안을 제시하고자 설문을 통하여 건강에 대한 인식, 신체활동을 위한 공원녹지의 이용실태 및 만족도 공원녹지를 이용한 신체활동 활성화를 위한 고려요소를 파악하였으며, 그 결과는 다음과 같다. 첫째, 응답자의 8.1%만이 건강에 대한 관심이 없다고 답변했을 뿐, 약 47.0%가 평소 건강에 관심이 있거나 많은 관심을 가진다고 응답하였다. 또한 95.2%의 응답자가 비만이 당뇨, 고혈압 등의 성인병에 영향을 준다는 사실을 알고 있었으며, 이러한 부분은 신체활동을 통해 상당부분 예방이 가능하다는 사실 또한 93.1%의 응답자가 인지하고 있었다. 둘째, 신체활동을 위해 이용하고 있는 공원녹지의 유형을 조사한 결과, '소규모 근린공원, 소공원'으로 응답한 인원이 200명으로 가장 높게 나타났으며 그 이유로는 '집에서 가까워서 이용하기 편리하기 때문'이라는 답변이 59.2%로 가장 많았다. 공원녹지에서 주로 이루어지는 신체활동을 묻는 문항에 대해서는 67.0%에 해당하는 262명이 '산책이나 걷기'와 같은 가벼운 신체활동을 하고 있다고 응답하였다. 이러한 신체활동은 '가족'과 함께 한다는 응답이 가장 높았으며, '친구', '혼자'가 그 뒤를 이었다. 이용 빈도는 74.8%가 주 1-2회 이하로 공원녹지를 이용하고 있어서 실질적인 건강이익을 기대하기 위해서는 좀 더 활발한 이용이 필요할 것으로 사료된다. 셋째, 신체활동의 활성화를 위한 공원녹지의 고려요소로는 '산책로'가 가장 높게 나타났으며, '양호한 접근성', '운동시설'과 '쾌적성'이 그 뒤를 이었다. 건강에 대한 관심이 증대되고 있는 요즘 신체활동의 장으로서 공원녹지의 역할에 대한 재고가 필요한 시점이라 판단된다. 앞에서 언급한 연구결과를 토대로 현 공원녹지의 불만요소를 개선하고, 새로운 공원의 조성 및 재조성 시 활성화 요소가 고려된다면 공원녹지를 이용한 신체활동이 더욱 활발해지리라 생각된다.

• The Journal of the Korea Contents Association
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• v.10 no.5
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• pp.52-61
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• 2010

In recent, the interests of multi-user systems have been increased. Multi-user systems allow a number of users to access the system simultaneously. Security is one of the key issues to be addressed in a multi-user environment. We propose a solution based on the NTFS file system that provides the personal data security and considers the convenience of users. The system increases the convenience of users by simplifying the complexity of the security setting on NTFS. We also propose a variety of policies that prevent from the conflicts incurring when different users set up the personal folders simultaneously and do not set up the important folders such as the window system folders as personal folders. In addition, our system supports the function of setting up the prohibition folder lists so that no one can not set the folder to their personal folders.

• Tunnel and Underground Space
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• v.21 no.6
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• pp.526-535
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• 2011

A new failure criterion for concrete, which takes into account the effect of the intermediate principal stress, is proposed. The new criterion, which takes the advantages from both the Mohr-Coulomb and the Willam-Warnke criteria, is linear in the meridian section, while its octahedral section is always smooth and convex. Fitting the triaxial compression data with the proposed criterion shows the high performance of the new criterion. A new formula for the factor of safety of concrete is defined based on the new failure criterion and it is employed in the stability analysis of the concrete plugs installed in the pilot plant. The new formula for the factor of safety measures the degree of closeness of a stress state to the failure surface in the octahedral plane. Finally, 3-D finite element analyses of pilot plant were carried out to obtain the stress distributions in the plugs. Then, the stress distributions are converted to those of factor of safety by use of the proposed formula. Based on the distribution of factor of safety in the concrete plugs, the stability of the tapered and wedge-shaped plugs is evaluated.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.5
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• pp.209-218
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• 2005

In this paper, we propose CIVE, context-based interactive system for heterogeneous distributed virtual environments that delivers contexts irom real world to virtual environment and vice versa. The proposed system ronsists of obi-UCAM for generating user's contexts, NAVER for managing virtual environment, and Interface for linking obi-UCAM with NAVER. The connection between real and virtual worid through context is brneficial in following ways. Firstly. CIVE Provides a personalized user interface for virtual environment according to a user profile such as identity, age and vernacular. Secondly, translating all input signals into context, it guarantees adaptive access that enables a user to exploit unencumbered input devices controlling a shared object in virtual environment even if he moves with his own device from a virtual system to another. Finally, it provides a mechanism for synchronizing distributed virtual systems that share context representing changes at remote nodes. The context reduces the inconsistency of representing the same data among heterogeneous systems. Therefore, CIVE plays an important role in implementing VR applications such as teleconference, game and entertainment.

• Health Policy and Management
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• v.21 no.1
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• pp.23-43
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• 2011

Access to health care is complicated to define. It is a multidimensional process. In addition to the matters of quality of care, geographical accessibility and availability of the right type of care, finance, and acceptability are all involved. The purposes of this paper are to measure the geographic distances between patient residency locations and health service organizations in which the patients hadvisited, and to investigate the association between geographical distance measures and variables involved in health service utilization. The study used the first and the second wave of the 2008 Korea Health Panel Survey. The samples of analyses were patients who had visited outpatient or used ambulatory health services, and the total observations (visit numbers) analyzed were 229,128. We divided the samples into a frequent-visit illness group (Group 1) and a non-frequent visit illness group (Group 2) based on over 5,000 total visit numbers. We exploited three level analyses using xtmixed of STATA${\Box}$ 11.1 command with/without interaction terms among age, sex, and occupation. Geographical distances were measured using the Haversine method. Group 1 was tended to older and lower equivalent income than those of Group 2, but the geographic difference were not observed in terms of area deprivation index and standard mortality ratios. Amongst group 1, diabetes mellitus patients travelled far to visit health care organizations, and arthritis patients were more deprived in terms of the personal and areal characteristics. The study revealed that residents in rural areas traveled about 10 times more long distances than those whom lived in larger cities after adjusting for various variables, which we used for analyses. This study contributed to the practical understanding of health service utilizations using empirical analyses, and found that the types of diseases and socioeconomic characteristics of patients tended to define the amount of travel distance to healthcare organizations.

• Journal of the Korea Society of Computer and Information
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• v.4 no.4
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• pp.47-56
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• 1999

We design and implement an ORDBMS-based geographic information system for sightseeing information of Chungbuk to verify the performance and applicability of GEUS/XTM ORDBMS. We Acquire the positional coordinates of the boundaries of administrative districts , roads, and railroads, determine the various kinds of information such as the locations of sightseeing sites, lodgings, and so on, design an object-relational schema using OMT, and implement the geographic information system including a database system. Through the examination of selective accessibility on the sightseeing inform ation database by the various queries, we conclude that the ORDBMS is more applicable than other DBMSs in modeling, storing, referring, and managing of non-fixed complex data such as sightseeing information. Therefore, ORDBMSs provide efficient and extensible implementations of databases and information services from various sources for the increasing demand on geographic information service on internet.

• 한국지구물리탐사학회:학술대회논문집
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• 2008.10a
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• pp.63-67
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• 2008

Geostatistical inverse approach using geophysical data was applied to indirectly make the RMR classification at points apart from boreholes. The geostatistical appoach was usually used to find optimized estimation which supports two or more different physical properties at unsampled points. However, in this study, an approach to solve inverse problem was proposed. The primary variable, RMR values obtained at known boreholes, is geostatistically simulated with many realization at pre-defined grid point according to the variogram model. The simulated values are sequentially compared with the physical property resulted from geophysical survey at an arbitrary grid point, and the most similar one is chosen. This process means that the spatial distribution of primary variable, RMR, is conformed well to the original pattern of the borehole observation, and ensure to fit the geophysical survey result to reflect the correlation between different physical properties.