• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.10
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• pp.3-9
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• 2016

Current mobile communication systems utilize the multiple-input multiple-output (MIMO) transmission technique as an important means to enhance the bandwidth efficiency. Accurate beamforming via channel estimation contributes to the signal-to-interference-plus-noise ratio (SINR) increase and the system performance improvement when MIMO transmission techniques are employed. Therefore, determination of beamforming vectors as well as the design of appropriate codebooks defining these codevectors play an important role in system operation. In this paper, we statistically analyze the phase difference between the channels corresponding to adjacent antenna elements in order to design an efficient codebook for uniform circular arrays (UCAs). We introduce new parameters which compensate for the additional phase difference observed in its probability density functions (PDFs). The performance of the proposed codebook is tested using the spatial channel model (SCM) to demonstrate its gain over the standard codebooks adopted in the long term evolution (LTE) Releases 8 and 10.

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.1
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• pp.37-47
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• 2002

Recently gasoline direct injection method has been applied to gasoline engine to reduce fuel consumption rate by controlling fuel air mixture on lean condition by means of stratified charging, and to reduce simultaneously. Pollutant emissions especially NOx and CO by lowering the combustion temperature. But difficulty of controling local fuel air ratio at ignition area in flammability limit unavoidably appeared, because it is merely controlled by injection timing with spatial and temporal distribution of fuel mixture. In this study, the authors devised a uniquely shaped combustion chamber so called three-chamber GDI engine, intended to keep the more reliable fuel air ratio at ignition area. The combustion chamber is divided into three regions. The first region is in the rich combustion division, where the fuel is injected from the fuel injection valve and ignited by the spark plug. The second region is in the lean combustion division, where the combustion gas from the rich combustion division flows out and burns on lean condition. And the last region is in the main combustion division ie in the cylinder, where the gas from the above two combustion divisions mixed together and completes the combustion during expansion stroke. They found that the stable range of operation of three-chamber GDI engine on low-load condition exists in the lean area of average equivalence ratio. And they also found that the reformed engine reveals less specific fuel consumption and less pollutant emissions compared with conventional carburettor type gasoline engine.

• Journal of Korean Society for Geospatial Information Science
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• v.12 no.3 s.30
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• pp.79-89
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• 2004

Despite of a huge amount of GIS data were distributed in the private sectors, they were gradually decayed due to lack of the legal preparation or civilian data distribution channels. In order to solve these problems this study was mainly focused on the civilian GIS data distribution and demonstrated a proposed direction through the requested questionnaire and analysis of the civilian enterprises and public sectors for the favorable civilian GIS distribution flow. The implementation of the civilian GIS data distribution center(provisional name) was proposed fir the civilian GIS distribution flow because of the fact that civilian sectors were seriously requested to build and to operate the civilian GIS distribution organization through the result of the requested questionnaire. The requested questionnaire items were selected as the civilian enterprises distribution, data implementation and management, low and regulations, NGIS distribution network business, and civilian GIS distribution renter build to activate and to participate civilian GIS distribution. Therefore, three implementation models and three implementation operation were proposed to guide a roll of the civilian GIS data distribution center and the distribution boundaries.

• Journal of Korean Society for Geospatial Information Science
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• v.15 no.4
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• pp.71-79
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• 2007

Land suitability assessment has been enforced by the National Land Planning and Utilization Act since 2003 to prevent urban sprawl and protect natural environment. It assesses developmental, agricultural or preservable suitability of land parcel according to such criteria as soil, location and usability by local governments. Land suitability assessment system (LSAS) has been introduced to prevent cursory development by urban sprawl and to lead a harmonious development with conservation in the non-urban area. However, with the lack of experience and knowledge various problems have been arisen in the operation of this system, raising a question for the improvement of the assessment unit of land. The purpose of this study is to investigate methods of developing land assessment as a sustainable land use management tool. In this study, land suitability assessment has been executed through geographic information systems. On the basis oh the results of analysis, practical and institutional problems are described, and technical and institutional solutions are suggested.

• Journal of Korean Society for Geospatial Information Science
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• v.25 no.2
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• pp.21-29
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• 2017

For the efficient and stable operation of autonomous vehicles or advanced driver assistance systems being actively studied nowadays, it is important to determine the positions of the vehicle accurately and economically. A satellite based navigation system is mainly used for positioning, but it has a limitation in signal blockage areas. To overcome this limitation, sensor fusion methods including additional sensors such as an inertial navigation system have been mainly proposed but the high sensor cost has been a problem. In this work, we develop a vehicle position estimation algorithm using in-vehicle sensors and a low-cost imaging sensor without any expensive additional sensor. We determine the vehicle positions using the velocity and yaw-rate of a car from the in-vehicle sensors and the position and attitude of the camera based on the single photo resection process. For the evaluation, we built a prototype system, acquired test data using the system, and estimated the trajectory. The proposed algorithm shows the accuracy of about 40% higher than an in-vehicle sensor only method.

• Journal of Korea Multimedia Society
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• v.9 no.11
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• pp.1381-1394
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• 2006

Generation methods of data cube have been studied for many years in data warehouse which supports decision making using stored data. There are two previous studies, one is multi-way array algorithm and the other is H-cubing algorithm which is based on the hyper-tree. The multi-way array algorithm stores all aggregation data in arrays, so if the base data is increased, the size of memory is also grow. The H-cubing algorithm which is based on the hyper-tree stores all tuples in one tree so the construction cost is increased. In this paper, we present an efficient data cube generation method based on hash table using weight mapping table and record hash table. Because the proposed method uses a hash table, the generation cost of data cube is decreased and the memory usage is also decreased. In the performance study, we shows that the proposed method provides faster search operation time and make data cube generation operate more efficiently.

• Journal of Korea Multimedia Society
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• v.13 no.10
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• pp.1494-1505
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• 2010

A variety of sounds take place in medium and small-sized manufactories producing many kinds of parts in a small quantity with one press. We developed the identification system for the quality of parts using HTM(Hierarchical Temporal Memory)-based sound recognition. HTM is the theory that the operation principle of human brain's neocortex is applied to computer, suggested by Jeff Hopkins. This theory memorizes temporal and spatial patterns hierarchically about the real world, which is known for its cognitive power superior to the previous recognition technologies in many cases. By applying the HTM model to the sound recognition, we developed the identification system for the quality of molding parts. In order to verify its performance we recorded the various sounds at the moment of producing parts in the real factory, constructed the HTM network of sound, and then identified the quality of parts by repeating learning and training. It reveals that this system gets an excellent and accurate results at the noisy factory.

• Journal of Korean Neurosurgical Society
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• v.47 no.6
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• pp.437-441
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• 2010

Objective : The precise intra- vs. extradural localization of aneurysms involving the paraclinoid internal carotid artery is critical for the evaluation of patients being considered for aneurysm surgery. The purpose of this study was to investigate the clinical usefulness of T2-weighted threedimensional (3-D) fast spin-echo (FSE) magnetic resonance (MR) imaging in the evaluation of unruptured paraclinoid aneurysms. Methods : Twenty-eight patients with unruptured cerebral aneurysms in their paraclinoid regions were prospectively evaluated using a T2- weighted 3-D FSE MR imaging technique with oblique coronal sections. The MR images were assessed for the location of the cerebral aneurysm in relation to the dural ring and other surrounding anatomic compartments, and were also compared with the surgical or angiographic findings. Results : All 28 aneurysms were identified by T2-weighted 3D FSE MR imaging, which showed the precise anatomic relationships in regards to the subarachnoid space and the surrounding anatomic structures. Consequently, 13 aneurysms were determined to be intradural and the other 15 were deemed extradural as they were confined to the cavernous sinus. Of the 13 aneurysms with intradural locations, three superior hypophyseal artery aneurysms were found to be situated intradurally upon operation. Conclusion : High-resolution T2-weighted 3-D FSE MR imaging is capable of confirming whether a cerebral aneurysm at the paraclinoid region is intradural or extradural, because of the MR imaging's high spatial resolution. The images may help in identifying patients with intradural aneurysms who require treatment, and they also can provide valuable information in the treatment plan for paraclinoid aneurysms.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.8
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• pp.1524-1530
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• 2016

Recently, research about an electronic attendance-absence recording system has been actively carried out using smart devices. Using an electronic attendance-absence recording system, professors can check their students' attendance on a real-time basis and manage their attendance records. In this paper, we proposed a real-time electronic attendance-absence recording system using face detection and face recognition based on web application. It can solve the spatial, temporal, cost issues belong to electronic attendance-absence recording system using AIDC(Automatic Identification and Data Capture). A proposed system is running on web server and made by HTML5(Hyper Text Markup Language ver.5). So professor connect to server using mobile web browser on mobile device and real-time manage electronic attendance-absence recording with real-time send or receive image data. In addition, the proposed system has an advantage capable of installation and operation, regardless of the operating system because it operates based on the Python flask framework.

• Journal of Cadastre & Land InformatiX
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• v.47 no.2
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• pp.201-212
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• 2017

The purpose of this study is to identify the problems of the present status of the Jeollanamdo's geographical name task by analyzing it and to suggest ways to improve it. For this purpose, the theoretical review including the definition of the geographical name as the subject of the study is conducted. Also, by analyzing the current structure of geographical name, the enactment and improvement of the ordinance of the committee on geographical name, and the management of committee on geographical name etc, the problems of the geographical name task are derived and suggestions for improvement are proposed. The results of this study are as follows: First, as a plan to improve the professionalism of the organization and the officer in charge of the geographical name task, this study suggests the unification of the department in charge of geographical name task, the specialization of the official in charge, and the development of training and teaching materials related to the geographic name task. Secondly, in order to improve the ordinance and the management of the committee on geographical name, this study suggests the enactment and improvement of the ordinance of committee on geographical name, the guidance and the supervision of the establishment and operation of the committee on geographic name, the simplification of procedures of establishing and changing geographical name, and enactment of geographic name a Law.