• KIPS Transactions on Software and Data Engineering
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• v.5 no.12
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• pp.677-684
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• 2016

For realistic rendering volume to calculate the light effects as well as the shade is essential. In order to produce the high quality of the resulting image, it is necessary to represent a global illumination, and it should be considered an indirect effect of the direct impact and scattering of light. It requires a lot of resources in order to perform this operation and, in particular, is very expensive when large amounts of data to be rendered as a volume data is consumed. In this paper, we generate a scatterer template according to the physical laws for each material. Considering that each object having material property stores photons of the template based on the Lambert illumination model. When the volume rendering in this paper, using the photon is stored in the template, based on the voxel to be sampled within the examination volume occluded, and it represents the global illumination of the scattering. Because the materials produced by the template requires a less resource only if comprised of a complex material, a simple operation can be expressed within the scattering volume at a low cost through.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.5
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• pp.665-675
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• 2001

In this paper, the reverse link performance of a imperfect power controlled DS/CDMA cellular system that uses a base station array antenna which can effectively remove the multiple access interference is analyzed considering both beam forming algorithm and power control error in shadowing. The blocking probability of the DS/CDMA cellular system based on array parameters, $E_b/N_o$ and statistics of interference is derived, and then the system capacity corresponding to a certain blocking probability is calculated. On the assumption that the blocking probability is set 1%, the system capacity using MCGM algorithm with 12 antenna arrays is more increased maximum 32 times than that using a omni-directional antenna and about 2 times than that using MMSE algorithm, respectively.

• Journal of Korean Society for Geospatial Information Science
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• v.4 no.2 s.8
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• pp.195-203
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• 1996

The 3-D analysis of terrain for route design and selection is being used as important basic data for effective judgement of political draft. This study is to decide efficient alignment of the entry route and design bridge by modeling, analyzing and displaying surface with digital terrain data. In this study we analyze slope, aspect, shaded-relief, line of sight and watershed on the base of DTM such as contour, TIN and grid. And we can not only esti mate end-area volume for road construction by calculating cut and fill and displaying mass-curve but also recognize the scene after execution with simulation of road and terrain. The result of this study reveals that visual effects of the 3-D terrain data are very effective for designer and decisionmaker to select and review alternative route with regard to terrain characteristics.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.7C
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• pp.642-650
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• 2010

Collaborative spectrum sensing allows secondary users scattered in location to work together to detect the activity of primary users and has been shown to significantly reduce the performance degradation due to fading phenomenon. Most previous works on collaborative spectrum sensing are based on the assumption that local spectrum sensing decisions of secondary users are statistically independent. However, it may not hold in some practical situations with shadowing effect. In this paper, we consider the case that the secondary users are evenly spaced in the form of a linear array and only adjacent secondary users are statistically correlated, and analyze the effect of the statistical correlation on the performance of collaborative spectrum sensing and the throughput of a cognitive radio network. Here we assumed the AND and OR fusion rules for combining the local decisions of secondary users. The analysis showed that the AND fusion rule achieves higher throughput than the OR fusion rule.

• Journal of Digital Convergence
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• v.14 no.8
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• pp.269-276
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• 2016

Public Safty-LTE(Long Term Evolution) is being deployed in the direction of reducing cost by using both of municipal network and commercial network. However, LTE Network is difficult to ensure the survivability during the information communication infrastructure failures. In addition, it is vulnerable in communication coverage of inside buildings and underground. In this study, we propose to implement effectively the network survivability technique through the convergence to the proven technology. As the advent of the IoT Age, smart sensors which are embedded in the environment and the things will be able to provide a useful infrastructure for ensuring the network survivability. Based on the feature of the smart sensor, we designed the sink node architecture to guarantee the network survivability in disaster situation through the convergence of the small cell technology and extension of wireless network coverage technology. The computing power inherent in the environment is a valuable resource that can be utilized in the disaster situation.

• Journal of Veterinary Clinics
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• v.30 no.3
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• pp.189-192
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• 2013

An 8-year-old, neutered female Korean short hair cat was referred with severe vomiting and anorexia. Abdominal mass effect was seen in the cranial abdomen on radiographs, and a mass with a heterogeneous echogenic pattern was observed medial to the right kidney on ultrasonography. On computed tomography, a large mass with soft tissue attenuation and a contrast-enhanced capsule was seen. In histopathological findings, the acinar structures were lined with irregular cuboidal cells that have pale eosinophilic cytoplasm and round to oval nuclei. Based on these diagnostic imaging and histopathological findings, the mass was diagnosed as pancreatic exocrine adenocarcinoma.

• Journal of the Korea Society for Simulation
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• v.20 no.1
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• pp.107-116
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• 2011

Recently, femtocell has been concerned as one of effective solutions to relieve shadow region and provide high quality services to users in indoor environments. Even though femtocell offers various benefits to cellular operators and users, many technical issues, such as interference coordination, network synchronization, self-configuration, self-optimization, and so on, should be solved to deploy the femtocell in current network. In this paper, we develop a simulator for evaluating performance of long term evolution (LTE) femtocell systems under various interference scenarios. The simulator consists of a main-module and five sub-modules. The main-module connects and manages five sub-modules which have the functionality managing user mobility, packet scheduling, call admission control, traffic generation, and modulation and coding scheme (MCS). To provide user convenience, the simulator adopts graphical user interface (GUI) which can observes simulation results in real time. We expect that this simulator can contribute to developing effective femtocell systems by supporting a tool for analyzing the effect of interference between macrocell and femtocell.

• Journal of Digital Contents Society
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• v.14 no.2
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• pp.191-197
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• 2013

To complete the "anywhere" mobile service there should not be shaded areas. However, it is never economical to deploy BS's (Base Stations) in a low population density area due to the low resource utilization. We propose a design technique to install RS's(Relay Stations) which are cheaper than BS's and find the condition in which the proposed technique is acceptible. The proposed design technique aims to allocate the frequency and time resources to RS's to minimize the transmission rate degradation due to interferences between RS's as well as to maximize the parallelism in transmission. We showed by simulation that the proposed technique achieves cost benefits when the expected traffic is less than 20.32 percent of the total BS capacity. The proposed technique is compatible with the IEEE 802.16j, thus can be extended to multi-hop configuration.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2A
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• pp.132-138
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• 2009

Cognitive radio is considered as a promising solution to scarce spectrum problem. The primary object of cognitive radio is to increase spectral efficiency, while causing limited interference to primary users who are using the spectrum. Hence, an essential part of cognitive radio systems is spectrum sensing which determines whether a particular spectrum is occupied or not by a primary user at a particular time. However, sensing decision of each individual secondary user alone may not be reliable enough due to shadowing and multipath fading of wireless channels. The so called hidden terminal problem makes the problem even worse, possibly yielding undesired interference to the primary users. Recently, cooperative spectrum sensing is emerging as a remedy to these problems of individual sensing. Cooperative sensing allows a group of secondary users to share local sensing information to extract a global decision with high fidelity. In this paper, we investigate a cooperative spectrum sensing algorithm based on hard decisions of local sensing outcomes. Specifically, we propose an effective scheme for combining local decisions by introducing weighting factors that reflect reliability of the corresponding secondary user. Through computer simulations, the performance of the proposed combining scheme is compared with that of the conventional scheme without weighting factors in various environments.

• Journal of Chest Surgery
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• v.34 no.4
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• pp.351-355
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• 2001

개흉술에 의한 수술적 폐쇄방법 및 경도관 동맥관 폐쇄술은 동맥관 개존중의 치료방법으로 발전되어 왔으나, 이러한 술식은 개흉술에 의한 합병증, 지속적인 단락 및 용혈의 가능성, 기구의 이동이나 색전증의 발생, 지속적인 단락시 세균성 심내막염 방지를 위한 지속적인 항생제 사용등의 단점이 있어 저자들은 흉강경을 이용한 수술을 시행하였다. 총 6례의 환자에서 흉강경을 이용한 동맥관 개존증 수술을 시행하였으며. 이중 대동맥 외막(adventitia) 박리중 지형이 잘 되지 않았던 1례에서는 소개흉술(minithoracotomy)로 전환하였다. 술 후 이시행한 이학적 검사상에서 모든 환아에 심잡음이 소실되었음을 확인할 수 있었으며, 흉부 방사선 검사상 점진적인 폐혈관음영의 감소를 관찰할 수 있었으며 수술중 동맥관 파열이나 불완전한 동맥관 폐쇄, 기흉, 애성(hoarseness) 등의 합병증은 발생되지 않았다. 환아들은 술후 평균 3.4일째 퇴원하였으며, 퇴원후 외래추적 관찰검사시 시행한 심초음파 검사상 동맥관의 재개통이나, 잔류단락은 관찰되지 않았다. 본원에서는 개흉술 및 경도관 동맥관 폐쇄술의 단점을 방지할수 있으며, 성공적인 동맥관 폐쇄, 작은 피부절개 반흔에 의한 미용적 효과, 짧은 재원기간등의 장점을 가진 흉강경을 이용항 동맥관 결찰술을 시해앟여 문헌 고찰과 함께 보고하는 바이다.