• Bulletin of the Korean Space Science Society
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• 2010.04a
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• pp.35.3-35.3
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• 2010

항공용 지역위성항법 보강시스템(Ground Based Augmentation System, GBAS)은 지상에서 위성항법시스템에 대한 위치보정정보와 무결성 정보를 생성 및 제공하여 공항 주변 항공기의 정밀 이착륙을 돕는 지상기반의 시스템이다. 이 시스템은 기본적으로 위성항법신호를 사용하기 때문에 전리층 영향을 받게 되는데 특히 전리층 폭풍(Ionospheric storm)의 경우 공간적으로 급격한 위치오차 차이를 발생시키기 때문에 안정적인 항공기의 정밀이착륙을 위해서는 전리층 폭풍의 영향을 최소화 하는 것이 중요하다. 이를 위하여 현재 항공용 지역위성항법 보강시스템의 지상시스템(Ground Facility)과 항공기 탑재시스템에서의 전리층 폭풍에 대한 정확한 감시와 전리층 폭풍의 지배적 영향을 받는 위상항법신호를 제거하거나 보완하는 방식 등 전리층 폭풍의 영향을 최소화하기 위한 기법들이 계속해서 연구 중이다. 이 논문에서는 2001년과 2003년 미국에서 발생한 전리층 폭풍에 대한 위성항법데이터 분석 결과와 기존의 연구결과를 기반으로 전리층 폭풍에 대한 모델링과 지상시스템과 항공기 간의 공간적 상이현상(Spacial decorrelation)을 고려하여 전리층 폭풍이 항공기 이착륙에 미치는 영향에 대한 분석 결과를 제시한다. 전리층 폭풍에 대한 수학적 모델링을 하기 위해서는 전리층 폭풍의 물리적 특성에 대한 이해와 전리층 폭풍 발생 시 획득한 위성항법 데이터를 이용한 통계학적 분석이 선행되며 이러한 분석결과와 항공기 이착륙에 절차를 반영하여 항공기에 미치는 영향 분석을 위한 수학적 모델을 완성하였다. 완성된 모델을 국내 공항에서 실제 비행시험을 통하여 획득한 위성항법데이터에 적용하여 전리층 폭풍이 국내 공항에서 항공기 이착륙에 어떠한 영향을 미치는지를 분석하였다. 또한, 대표적 전리층 폭풍 감지기법 중 하나인 Code-Carrier Divergence Test 알고리즘을 적용한 결과도 함께 제시하였다. 이 논문의 결과는 항공용 지역위성항법 보강시스템에 대한 전리층 폭풍의 영향을 최소화하기 위한 기법 연구의 기반이 되며 시스템의 성능평가를 위한 다양한 시뮬레이션환경의 하나로서도 활용이 가능할 것이다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5849-5855
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• 2011

As application development environment changes rapidly, importance of user interface design is increasing. Usually, most of designers are clustering by subjective method of individual to define objects that have relativity in design interface. But, interface which is designed without particular rules just adds inefficiency and complexity of business to user who use this system. Therefore, in this paper, we propose an object oriented design model that allows for flexible development by formalizing the user interface prototype in any GUI environment. The visual cohesion of the user interface is a new set of criteria which has been studied in relation to the user interface contents, and is founded on the basis of the cohesion of the interface as defined using basic software engineering concepts. The visual cohesion includes the issue of how each unit is arranged and grouped, as well as the cohesion of the business events which appear in the programming unit. The interface will become easier to understand and use if the business events are grouped by their inter-relevance within the user interface.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.3
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• pp.645-653
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• 2004

The prediction and its visualization on fish behaviour in relation to fishing gear are carried out based on field detection and observation during fishing operation. However, field observation is very difficult due to variable underwater environments and accordingly due to complex, chaotic response of fish behaviour in the physiological and ecological points. Therefore simple graphic display in previous results was not enough to represent real underwater images of the fishing gear and fish behaviour. In this study more actual visualization technique was developed using by previous fish behaviour model with chaos theory in order to predict, evaluate or analyse complex and non-linear phenomena of response patterns in complex fish behaviour. In addition, display of the fish finder was also designed to simulate the underwater fish detection and distribution in fishing ground. This suggested visualization tool was very similar to the information of the fish movement in the field observation in visual underwater reality and useful to check up between simulations and observations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.7
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• pp.1568-1574
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• 2009

One of the most difficult problems in user requirement engineering is the communication gap that exists between different end-users, stakeholders, and software engineers. Since scenarios allow different stakeholders to describe and review the problem in their own language instead of some abstract model, they are also a solution to the problem. We propose a progressive, iterative and interleaved process of using scenario at different requirement engineering stages including elicitation, analysis and validation. This process model has been applied to our TRES System. In our proposed system, we combine prototype, scenarios and use cases in a single and comprehensive framework to avoid most of the shortcomings in other tools. Our system is an XML-based system for scenario-driven requirement engineering. Within the TRES system, scenarios are stories capture information about users and their tasks, including the context of use. In our TRES system, scenarios are stored in XML-based database and described using XML notation.

• The KIPS Transactions:PartD
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• v.16D no.2
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• pp.177-184
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• 2009

Environmental monitoring systems are widely developed for analyzing environment and understanding an ecosystem according to the advance of wireless communication and various sensing techniques. To extract useful information, it requires high cost for processing a query, because these systems have to handle huge volume of raw sensor data which is transmitted from a wide area in environmental monitoring applications. Besides, it is also hard to answer an user defined query which requests to check current and near future condition. In this paper, we propose the monitoring system structure for processing a user defined query for environmental monitoring. It also describes the utilization of sensor data filtering and abstraction model. The designed abstraction model which is based on the slope grid in GIS supports fast data access and update. To analyze condition, the extracted data from abstraction model of each sensor type is combined in a query processor. It is useful to provide meaningful information to users.

• Journal of the Korean Geographical Society
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• v.38 no.6
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• pp.906-921
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• 2003

This paper discusses the price effects of local growth controls on the housing markets of California jurisdictions in the late 1980s empirically. Particularly, based on spatial econometric modeling, the study focuses on the homebuilding constrained by growth controls which is one of the price effects. The modeling produces the California-wide generalizable results, differentiates among the individual effects of various growth controls on homebuilding, and covers spatial effects. Thereby, this study intends to supplement the existing work on the price effects of growth controls. The modeling results find that restrictive residential zoning had the effect of significantly restricting housing construction in the late 1980s. On the other hand, urban growth boundaries had the effect of accommodating homebuilding. Population growth or housing permit caps and adequate public facility ordinances had no significant effects on housing construction.

• Tunnel and Underground Space
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• v.18 no.2
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• pp.134-148
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• 2008

The state of in situ stress is an important factor in considering the suitability of a site as a geological repository for nuclear waste. In this study, three-dimensional distinct numerical analysis was conducted to investigate the effect of deformation zones on the state of stress in the Oskarshamn area, which is one of two candidate sites in Sweden. A discontinuum numerical model was constructed by explicitly representing the numerous deformation zones identified from site investigation and far-field tectonic stress was applied in the constructed model. The numerical model successfully captured the variation of measured stress often observed in the rock mass containing large-scale fractures, which shows that numerical analysis can be an effective tool in improving the understanding of the state of stresses. Discrepancies between measured and modelled stress are attributed to the inconsistent quality of measured stress, uncertainty in geological geometry. and input data for fractures.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.8-14
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• 2017

Nonstructural components, such as electrical equipment, have critical roles in the proper functionality of various infrastructure systems. Some of these devices in certain facilities should operate even under strong seismic shaking. However, it is challenging to define each mechanical and operational failure and determine system failure probabilities under seismic shaking due to the uncertainties in earthquake excitations and the diversity of electrical equipment, among other factors. Therefore, it is necessary to develop effective and practical probabilistic models for performance assessment of electrical equipment considering variations in equipment features and earthquakes. This study will enhance the understanding of the effect of rocking behavior on nonstructural equipment, and linear-to-nonlinear behavior of restrainers. In addition, this study will generate probabilistic seismic demand models of rigid equipment for a set of conventional and novel intensity measures.

• Annual Conference of KIPS
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• 2014.04a
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• pp.192-195
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• 2014

u-Health 서비스는 의료기술에 ICT을 접목하여 보다 나은 건강관련 서비스를 제공할 수 있는 패러다임이다. 그러나 이러한 시스템을 도입하기에는 현실적으로 많은 도전이 존재한다. 개인의 건강관리 도구로 존재할 수 있을 것처럼 보이는 이러한 서비스는 그것이 국민의료의 질과 연관되는 이슈로 확대될 때, 환자라는 소비자집단, 의료인이라는 공급자집단, 그리고 국가라는 보건행정을 담당하는 관리집단의 이익이 첨예하게 대립할 수 있는 이슈가 될 수 있다. 이에 본 연구에서는 이러한 서비스의 제공을 이러한 개개 이익집단의 관점에서 탈피하고 순수한 양질의 의료 서비스 제공의 관점에서 살펴보아 과연 어떠한 ICT 관련 서비스 제공이 의료 환경 제고를 위해 필요한지를 파악해 보고자 하였다. 특히, 원격지에서의 자료공유를 통한 의료 서비스의 질 제고에 대해 관심을 가지고 이를 이익집단간의 이해관계가 크지 않은 ODA국가를 대상으로 하여 적용할 수 있는 서비스 모델을 제안하고자 하였다.

• Korean Journal of Remote Sensing
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• v.12 no.2
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• pp.155-168
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• 1996

Speckle noise has been a primary concern to many applications of synthetic aperture radar (SAR) imagery. In recent years, several satellites with radar imaging systems were launched and the use of SAR data are expected to be increased rapidly The objectives of this study are to provide introductory understanding on radar speckle filtering and to compare the effects of several filtering methods that are relatively unknown to user community. Two study sites were extracted from the RADARSAT SAR data obtained over the suburban areas near Seoul. The study sites include relatively homogeneous cover types, such as reservoir, parking lot, rice pad, and deciduous forest. Five filters (mean filter, median filter, sigma filter, local statistics filter, and autocorrelation filter) were applied to the SAR imagery and their effects were evaluated from the aspects of both image smoothing and edge preservation. In overall, the evaluation results indicate that the local statistics filter and autocorrelation filter, that are based on a speckle model, are more effective to suppress speckle within homogeneous cover type while maintaining the edge sharpness between cover types.