• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.2
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• pp.180-185
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• 2015

As the number of document resources is continuously increasing, automatically extracting keyphrases from a document becomes one of the main issues in recent days. However, most previous works have tried to extract keyphrases from words in documents, so they overlooked latent keyphrases which did not appear in documents. Although latent keyphrases do not appear in documents, they can undertake an important role in text summarization and information retrieval because they implicate meaningful concepts or contents of documents. Also, they cover more than one fourth of the entire keyphrases in the real-world datasets and they can be utilized in short articles such as SNS which rarely have explicit keyphrases. In this paper, we propose a new approach that selects candidate keyphrases from the keyphrases of neighbor documents which are similar to the given document and evaluates the importance of the candidates with the individual words in the candidates. Experiment result shows that latent keyphrases can be extracted at a reasonable level.

• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.6
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• pp.542-550
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• 2015

Usually, a new SSD (Solide State Drive) product is developed based on the software platform of the previous product. Therefore, when using the same test case was used to evaluate the previous generation evaluation of new products are a number of advantages may be, but a priority or weight is the inefficiency exists in the use of the evaluation resources due to not considered. A new method is proposed to prevent the waste of testing resources. Through the analysis of the evaluation data for the previous products, the combinations of testing cases with the highest probability for defect detections are identified. When the software is to be reused, most part of the base software platform is rarely modified and only some modules are added or modified. So, the whole software system may have similar types of defects with the previous products. By utilizing the evaluation data for the previous proucts, we can detect defects at an early stage.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.1
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• pp.187-192
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• 2015

Underwater acoustic communication channels have very complex channel characteristics caused by time-varying sea surface, submarine topography, sound speed, and geometry between transmitter and receiver. Especially, the channel has time-variance and doppler effect due to wind and sea current. We have to recognize the channel state and apply it to communication technique for increasing transmission efficiency in the underwater acoustic channel. In this paper, we present the frame recursive modulation and demodulation method using ambiguity function and autocorrelation function to estimate the doppler frequency. Furthermore, we conducted the simulation and sea experiment to evaluate the performance of the proposed method. When the channel coding technique was not used, the bit error rate performance of the proposed method was improved about 32 % compared with conventional method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.3A
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• pp.319-326
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• 2008

All over the world more than 2,000 VORs(VHF Omni-directional Ranges) including 39 in Korea are being operated for formulating air routes. But VOR reveals some difficulties in cost and time when relocating already an installed one due to its poor performance from the interference by its geometrically surrounding obstacles. DVOR(Doppler VOR) which is more popular than CVOR(Conventional VOR) has huge antennas and make it very difficult to assume a sufficient number of proper site candidates for permanent installation. This paper develops an efficient method for predicting proper site of DVOR installation by isolating transmitter from sideband antennas and counterpoise, making the transmitter easily moveable and verifying the performance of DVOR only with a transmitter and an antenna. The method was tested with a real flight measurement for DVOR performance around Gwangju Airport in Korea.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.1
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• pp.43-56
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• 2013

Personal Rapid Transit(PRT), which is one of the next generation convergence transport technology, PRT system requires operation technology for controlling diverse vehicles and dealing with a variety of abnormal driving situations on a large scale trackway structures in expected operational area more efficiently and reliably. Before developing PRT control technology, it is essential that multiple testing procedures stepwise with building small scale test-tracks and develop real unmanned-vehicles. However, it is expected that the experiments demand huge amount of time and physical cost. Thus, simulation in virtual environment is efficient to develop wireless based control technology for multiple PRT vehicles prior to building real-test environment. In this paper, we propose a VR-based integrated simulator which physics engine is applied so that it enables simulation of front-wheel-steering PRT system rather than simple rail track system. The proposed simulator is also developed that it can reflect geographical features, infrastructures and network topology of expected driving region.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.2
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• pp.83-92
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• 2018

Using ground moving target indicators equipped with synthetic aperture radars for locating moving targets within a wide background clutter in a short time is an excellent method for monitoring traffic. Although the displaced phase center antenna (DPCA) technique and along track interferometry (ATI) are real time methods with low computational complexity, they are essential for reducing cases of false alarm that can result in poor performance. In this paper, we propose two detection methods using DPCA and ATI-the parallel fusion method and serial fusion method. Simulation results demonstrate that the proposed detection methods are characterized by low probability of false alarm along with good performance. In particular, the serial fusion method possesses high detection probability along with low probability of false alarm (1/5th of the false alarm probability of the DPCA technique).

• Journal of Korea Game Society
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• v.13 no.2
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• pp.49-58
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• 2013

In this study, a tree growth model is designed to represent a variety of trees consisting of a outdoor terrain of game efficiently and naturally. The proposed tree growth model is an integrated tree growth model, and is configured using the following approaches: (1) the tree modeling method based on growth volume and the convolution sums of divisor functions, which is used to model a variety kind of trees more intuitively and naturally; (2) a rendering method using a level of detail of branch based on instancing for real-time processing of numerous trees with complicated structures; and (3) a combination of the above methods to efficiently implement a game landscape. The natural and diverse growths of trees that emerged using the proposed tree growth model is evaluated through experimentation, along with the possibility of implementing the natural game landscape and the efficiency of real-time processing.

• Journal of the Korean GEO-environmental Society
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• v.13 no.8
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• pp.25-33
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• 2012

Although it is important to reflect the accurate information of the ground condition in the tunnel design, the analysis and design are conducted by limited information because it is very difficult to consider various geographies and geotechnical conditions. When the tunnel is under construction, examination of accurate safety and prediction of behavior are overcome the limits of predicting behavior by Artificial Neural Network in this study. First, construct the suitable structure after the data of field was made sure by the multi-layer back propagation, then apply with algorithm. Employ the result of measured data from database, and consider the influence factor of tunnel, like supporting pattern, RMR, Q, the types of rock, excavation length, excavation shape, excavation over, to carry out the reliable analysis through field applicability of Artificial Neural Network. After studying, using the ANN model to predict the shearing displacement, convergence displacement, underground displacement, Rock bolt output follow the excavation over of tunnel construction field, then determine the field applicability with ANN through field measured value and comparison analysis when tunnel is being constructed.

• Journal of the Korean Institute of Rural Architecture
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• v.18 no.3
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• pp.17-24
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• 2016

The aim of this study is to build an architectural landscaping design ways of vulnerable community in rural area. I surveyed scenery structures, public buildings and single home forms, and fence types of house in twelve villages which have undertaken improving environment of rural community in four provinces. They all have an inferior surroundings to live in rural village, because they were isolated from the city, located on the mountain or island, and made a living under the slate materials of roof. The central government has been driving to reform the conditions with local office, so that they may increase their living qualities and village environment to get to the general level of rural area. There are three results of this study as follows: First, the scenery of the village surveyed has a remarkable views of locality and hierarchy of layers between field and mountain, which is very identified as a typical image of Korean rural topology. Second, the public buildings and single homes and outside wall of houses were personally designed or reformed as a various types like a flat slab style and different architectural structure, because they followed only to keep the architectural code rather than to make a harmony with other traditional style buildings. When they have to remodel it again through SaethulMaul project, they are needed to consider of both architectural code and design guideline for the local landscape design image. Third, to make a different landscape view of each village and improve housing conditions, it should be taken a people participation design way.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.177-180
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• 2005

AIS needs high efficiency and safety in terms of operational management and, in the aspect of service range, it is time to minimize shadow regions through propagation evaluation of AIS transmitter. Thus this study analyzes shadow regions and the scope of propagation of waves from stations through the electric wave environment of AIS. First, this study examines the characteristics of AIS wave and draws up methods to analyze the scope of propagation of waves according to the characteristics. Second, this study finds out service regions and shadow regions of the 22 stations across the nation by analyzing the actual data based on climate and topography, Lastly, this study summarizes the results of wave conductivity evaluation and conductivity problems and proposes improvement measures.