• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.1
• /
• pp.157-162
• /
• 2011

In this paper, we propose enhanced methods of path finding based on an abstract graph with extension of search space to improve the quality of path. The proposed methods that are called simple buffering method, velocity constrained method and distance constrained method are to extract buffering-cells for using search space with valid-cells. The simple buffering method is to extract adjacent cells of valid-cells as buffering-cells. velocity constrained method and distance constrained method are based on simple buffering method, these eliminate buffering-cells through each of threshold. In experiment, proposed methods can improve the quality of path. The proposed methods are applicable to develop various kinds of telematics application, such as path finding and logistics.

• Journal of the Korea Society of Computer and Information
• /
• v.13 no.3
• /
• pp.15-25
• /
• 2008

Recently, with the growing use of e-learning, instructors develop new online courses using a variety of contents and then store the results on their computers. These contents should be updated with new information as time goes on, and a new content also can be produced by reusing these ones. However, a lot of time will be needed for instructors to search, edit, and manage various contents stored from place to place on their computers. Currently, the development of the e-learning content management tool. which performs efficiently these functions on the PC environment, leaves much to be desired. Therefore, in this paper, we proposed an e-learning content creation and management system which can manage efficiently a variety of contents stored from different locations on an instructor's computer and can develop easily new online courses. The proposed system can be used widely to develop contents for instructors based on the PC environment. For performance evaluation, this paper compared the proposed system with the previous system according to the retrieval time of content keyword, and the experiment showed that our system is much better than the previous one.

• Korean Journal of Construction Engineering and Management
• /
• v.10 no.6
• /
• pp.3-12
• /
• 2009

In order to effectively distribute the resources, it is very critical to understand the status or progress of construction site quickly and accurately. Augmented Reality (AR) can provide this situation with information which is convenient and intuitive. Conventional implementation of AR in outdoor or construction site condition requires additional sensors or markers to track the position and direction of camera. This research is aimed to develop the technologies which can be utilized in gathering the information of constructing or constructed buildings and structures. The AR technique that does not require additional devices except for the camera was implemented to simplify the system and improve utility in inaccessible area. In order to do so, the position of camera's perspective center and direction of camera was estimated using exterior orientation techniques. And 3D drawing model of building was projected and overlapped using this information. The result shows that by using this technique, the virtual drawing image was registered on real image with few pixels of error. The technique and procedure introduced in this paper simplifies the hardware organization of AR system that makes it easier for the AR technology to be utilized with ease in construction site. Moreover, this technique will help the AR to be utilized even in inaccessible areas. In addition to this, it is expected that combining this technique and 4D CAD technology can provide the project manager with more intuitive and comprehensive information that simplifies the monitoring work of construction progress and planning.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.28 no.4
• /
• pp.507-514
• /
• 2022

Jinhae Bay is used as a major typhoon shelter in the southeastern region of Korea. However, when a typhoon strikes, the Jinhae Bay is facing the possibility of marine accidents caused by dragging anchors and the increased number of ships. This paper suggested ways to safely and efficiently manage the port of Jinhae Bay when a typhoon strikes from Vessel traffic service operators in the sea, derived relative importance by conducting an Analytic Hierarchy Process assessment to ship operators, and suggested safety measures reflecting manager and user opinions. In order to select safety measures factors for the AHP survey, VTS operators analyzed the evaluation of measures when a typhoon strikes in Jinhae Bay. As a result of conducting a survey based on the selected safety measure factors, it was found that ship operators consider the safety of ships more than twice as important as efficient management, and comprehensively consider them in the order of management of evacuated ships, management of anchorage area, management of evacuation information, preparation regulations and guidelines, improvement of system equipment, education, publicity, and notification activities. Through the measures and relative importance identified in this paper, it is believed that Jinhae Bay can serve as the basis for safely and efficiently managing typhoon shelters.

• Journal of KIISE:Software and Applications
• /
• v.37 no.10
• /
• pp.760-767
• /
• 2010

There are many memory leak detection tools. However, programmers, who develop very large programs, tend to avoid testing their programs with memory leak detection tools since these tools require runtime and space overheads. Thus, we present a memory leak detection technique which enables programmers to test their modules in their unit test phase with low overheads. To achieve this goal, we extend the existing cyclic memory allocation technique and evaluate our memory leak detection technique on a tiny DBMS. In our experiments, we find our tool has reasonably low runtime and space overheads and it reports only a small number of false positives.

• KIPS Transactions on Software and Data Engineering
• /
• v.6 no.2
• /
• pp.85-90
• /
• 2017

Various mobile devices are spreading in recent developments in mobile computing environments. Especially the popularity of mobile devices equipped with GPS has become widespread, and various application services utilizing location information are born. In this paper, we propose a system model for storing and managing the trajectory of moving objects, which is the set of location information of moving objects acquired in continuous time, and the UDF (User-Defined Functions) based trajectory index method which can quickly query the large data set of moving object and the Pre-Materialized table method. Then we compare and evaluate the performance of each method through experiments. Experimental results show that the Pre-Materialized table method is about 1.2 times faster than the UDF based trajectory index method on execution time.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.24 no.1
• /
• pp.85-90
• /
• 2010

This paper presents a technique to evaluate the reliability of customers in Community Energy System(CES). Operators of the CES are responsible for a reliable energy supply to their customers. Due to the strategy of the priority on their customers, the restoration process of DGs should be reordered when system outage happens. The previous study has proposed the technique in the distribution system in which one operator owns all DGs. Case studies in Bus 2 of Roy Billinton Test System(RBTS) verify that the accuracy of the proposed technique is comparable to that of previous technique, and the distribution system divided into several CESs changes the reliability index of customers in the CESs.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.2A
• /
• pp.168-175
• /
• 2006

To cope with channel variation, wireless networks such as IEEE 802.11 WLAN provide multiple transmission rates by employing different channel modulation and coding schemes. However, the coexistence of different transmission rates degrades the total system performance of the network. In order to eliminate this performance abnormality and improve protocol capacity, we propose a new Packet transmission algorithm, the RAT(Rate-Adapted Transmission) scheme. The RAT scheme distributes the wireless channel fairly based on the channel occupancy time. Moreover, it efficiently transmits packets even in a single station using rate-based queue management. Therefore, the RAT scheme obtains not only the inter-rate contention gain among stations but also the intra-rate contention gain among connections in a single station.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.31 no.2B
• /
• pp.99-108
• /
• 2011

In this study a hybrid design scheme for the purpose of designing infiltration-based retentions and a detention is applied to reproduce urban hydrologic regime to natural hydrologic regime. The proposed method is based on the NRCS-CN stormwater estimation technique, and applied to determine the size for stormwater control facilities on the Oncheon stream as an example. Urban area, corresponding to less than 70 m height of the Oncheon stream basin area is targeted. The results indicate that the proposed scheme is very useful to reproduce its undeveloped flow-duration curve.

• Proceedings of the Korean Information Science Society Conference
• /
• 2007.10c
• /
• pp.185-190
• /
• 2007

대용량의 자료가 생산됨에 따라 데이터를 효율적으로 저장, 관리, 이용할 수 있는 데이터 웨어하우스의 역할이 중요하게 되었고, 그에 따라 자료 처리 기법의 개발은 필수 과제가 되었다. 품질 평가와 오류 판단, 결측 보정의 자료 처리 과점은 자료의 신뢰도를 판단하고 활용도를 높일 수 있는 과정으로 매우 중요하다. 본 논문에서는 우리나라의 실제 교통상황을 반영하고 평가 기준의 오차를 줄이면서 더욱 간단 명료한 평가 계산식을 도입하여 효율적인 품질평가와 오류판단, 결측 보정의 자료 처리 기법을 제안한다. 또한 오류 판단 기준에 새로운 파라미터론 도입하여 교통 연구자의 요구 사항을 반영할 수 있게 하였다. 결측 보정 과정은 여러 기법을 연구하고 기존의 결측 보정 기법에 입력 변수를 추가하여 실제 대용량의 교통 자료에 적용하였다. 그리고 교통 자료가 저장되는 데이터베이스에 직접 접근하여 결측 보정과정을 수행하도록 PL/SQL로 구현하였으며, 이를 통해 교통 연구자에게 쉽고 다양한 방법으로 결측 보정을 수행하고 그 결과를 이용하여 다양한 교통 정보를 가공할 수 있는 환경을 제공하였다.