• Journal of the Korean Institute of Gas
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• v.18 no.6
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• pp.40-44
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• 2014

In this study, it is analyzed that a change in the shape of small propane containers made of STS304 when increasing of internal pressure. When internal pressure of a small propane container increased, bottom of end plate is convexly changed. This test is applied to a water bath pressure test to analyze the characteristics of the container. Water bath is able to analyze relationship between internal pressure and volume. In result, shape change section is confirmed because bottom of end plate is convexly changed. In addition, this section tend to decrease internal pressure because a volume increment increase out of proportion to pressure. The results of this study are expected to contribute to improving the safety of the pressure vessel, as well as various small propane container.

• 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 Navigation and Port Research
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• v.38 no.3
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• pp.211-216
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• 2014

In this paper, high throughput method is studied to provide floating objects with broadband service as ship by using satellite. In recent, satellite broadcastings standard is based on DVB-S3 for communication service using wireless device on navigation communication by satellite. LDPC codes are iterative coding algorithm proposed in DVB-S3. In this paper, FTN technique is applied to LDPC codes with 8-PSK modulation and then present the method to alleviate performance degradation due to FTN through BICM-ID. BICM-ID is the method to improve performance by calculating a new LLR from hard-decision value of decoder output. DVB-S2 system with 8-PSK modulation and FTN technique based on iterative decoding had a better performance than DVB-S2 with 8-PSK modulation and FTN technique over Gaussian channels.

• Journal of the Korea Convergence Society
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• v.8 no.4
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• pp.287-295
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• 2017

The purpose of this study is to find the characteristics of the blindness of Sim Bongsa, Sim Cheong's father, in Sim Cheong Jeon (the story of Sim Cheong). This is one of the representative works about the filial piety in Korea. This article regards the story as the process of restoring the sight of the father and tries to examine the cause and the timing of his blindness to make its diagnosis in the psychoanalytic perspective. The predominant characteristics of Sim Bongsa were very dependent and irresponsible. He was so unqualified to be a head of a family. He sought to close his eyes toward reality in his unconsciousness. His blindness can be diagnosed as a case of psychogenic hysteria, conversion disorder. The fact that he suddenly could see when the empress turned out to be his own daughter, Cheong, can be a meaningful proof for this diagnosis. It means that his symptom of blindness disappeared when he realized a new reality which ensures a comfortable and easy-going life for himself.

• (The)Study of the Eastern Classic
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• no.43
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• pp.65-92
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• 2011

, or The Story of Jeonuchi, is a classical Korean novel written at an unknown date by an unknown writer. It has a few different editions presumably because they were printed from a variety of different woodcuts carved in a few dialects. The present study examines The Story of Jeonuchi based on one of its earliest editions collected by the Academy of Korean Studies. Focused on the novel's main ideas of educational value, the author explores effective educational means to teach these ideas to college students. The novel's main ideas with edifying qualities include: alleviating resentment of the people, punishing the greedy, promoting filial piety and loyalty to the sovereign, and antagonism between disloyal forces. And these ideas can be effectively discussed in class using brainstorming, demonstration and logical description. Changing time requires a different approach to understanding and appreciating classical novels. Based on this awareness, the study seeks to find an effective way to teach today's students about literature from a different time. It also stresses that this process involves encouraging the students to logically express their ideas in writing.

• Journal of Chest Surgery
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• v.39 no.8 s.265
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• pp.588-597
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• 2006

Background: The surgical repair of a tetralogy of Fallot (TOF) has been performed successfully with a favorable early and late outcome. However, the later development of pulmonary regurgitation and stenosis remains a problem. The development of pulmonary regurgitation and stenosis may be changed by the size of right ventricular outflow tract (RVOT) reconstruction at the initial total correction. Hence, it is necessary to investigate the ideal size of RVOT reconstruction. Material and Method: This prospective study was carried out to determine how a surgical strategy and the RVOT size affect the occurrence of pulmonary regurgitation and stenosis. From January 2002 to December 2004, 62 patients underwent the TOF total correction. The RVOT size (diameter of pulmonary valve annulus) of each case was measured after the RVOT reconstruction and converted to a Z value. A pre-scheduled follow up (at discharge, 6 months, 1 year, 2 years and 3 years) was carried out by echocardiography to evaluate the level of pulmonary regurgitation and stenosis. Result: The patients were divided to two groups (transannular group n=12, nontransannular group n=50) according to the method of a RVOT reconstruction. The Z value of RVOT=iameter of pulmonary valve annulus) (transannular group -1, $range\;-3.6{\sim}-0.8;$ nontransannular group -2.1, $range\;-5.2{\sim}-1.5)$ and the average pRV/LV after surgery ${(transannular group 0.44{\pm}0.09,\;nontransannular group\;0.42{\pm}0.09)}$ did not show any significant difference between two groups. The occurrence of pulmonary regurgitation above a moderate degree was more frequent in the transannular group (p<0.01). In nontransannular group, the development of pulmonary regurgitation more than moderate degree occurred to the patients with larger RVOT size (Z value>0, p<0.02) and the progressing pulmonary stenosis more than mild to moderate degree developed in the patients with smaller RVOT size (Z value<-1.5, p<0.05). A moderate degree of pulmonary stenosis developed for 4 nontransannular patients. Three underwent additional surgery and one underwent a balloon valvuloplasty. Their Z value of RVOT were -3.8, -3.8 -2.9, -1.8, respectively. Conclusion: When carring out a TOF total correction, transannular RVOT reconstruction group has significantly more pulmonary regurgitation. In the nontransannular RVOT reconstruction. the size of the RVOT should be maintained from Z value -1.5 to 0. If the Z value is less than -1.5, we should follow up carefully for the possibility of pulmonary stenosis.

• Journal of Energy Engineering
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• v.23 no.3
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• pp.146-149
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• 2014

Compared to Butane tank, the propane tank should have a higher compressive strength due to its higher vapor pressure. In this study, a theoretical analysis was performed to evaluate the effect of change in the geometry of bottom plate on the mechanical property of tank, and an experiment was also carried out to observe the propensity of the deformation and failure of the vessel using hydraulic pressurizing device. The compressive strength of the vessel was observed to improve 1.5-2.5 MPa as the curvature of the bottom plate was decreased 62 mm and the thickness of the bottom plate was increased 0.25 mm. This study are expected to provide viable information conducive to achieve on-going development of a small vessel for the pressurized propane gas.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.2
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• pp.184-191
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• 2017

This paper presents cluster based hybrid spectrum sensing system for M2M services. For each cluster, secondary nodes within the transmission radius of the primary node use hard decision method through local spectrum sensing to determine whether the primary node exists. And the other secondary nodes and the secondary nodes having poor radio channel conditions judge the existence of the primary node through the soft decision method of the values obtained by performing the cooperative spectrum sensing. In the proposed hybrid spectrum sensing system, the performance according to the number of secondary nodes is analyzed with the conventional system over Rayleigh fading channel. As the number of cooperative sensing users increased to 2, 3 and 4, the cluster error probability decreased to 0.5608, 0.5252 and 0.4001 at SNR of -10[dB] respectively. Since the proposed system uses less overhead traffic, it is found that it is more effective in terms of frequency usage than the conventional system using soft decision-soft decision and soft decision-hard decision methods.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.8A
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• pp.1441-1449
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• 2001

차세대 멀티미디어 이동통신인 IMT-2000의 규격에서는 3GPP와 3GPP2에서 모두 터보 코드를 채널 코덱으로 채택하고 있다. 그 중 3GPP 에서는 용도에 따라 길쌈부호와, 제한길이 4인 1/3 터보코드를 선택적으로 사용하도록 정의되어 있다. 터보코드는 복호기의 출력으로 경판정 복호 비트에 대한 신뢰도 값을 동시에 생성하여, 이를 이용한 반복복호로 우수한 BER 특성을 얻을 수 있어야 한다. 본 논문에서는 먼저 3GPP 규격의 터보 복호기에 적용할 수 있는 내부 복호기로서 SOVA 복호기를 설계하였다. 또한 터보 복호기에서의 연판정 출력값의 중요성을 감안하여, 누적메트릭 정규화에 있어서 신뢰도 값에 영향을 주지않는 구조를 제안하여 적용하였다. 본 연구에서는 효율적인 구조의 3GPP SOVA 복호기를 설계하기 위하여 C++를 이용하여 알고리즘에 대한 성능을 검증하였으며, 이를 기반으로 VHDL을 이용하여 복호기를 설계하였다. 마지막으로 Altera사의 EPF10K100GC503 FPGA를 이용하여 복호기를 하드웨어로 구현하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4B
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• pp.324-330
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• 2002

In this paper, we proposed a simple modification on Fiebig's REC algorithm for multiuser detection of FH/MFSK systems replacing hard limiter with soft limiter. The performance improvement of our modified REC algorithm has been confirmed with computer simulations. for the parameter of interest, the capacity could be increased about 5% or more without degrading the reliability.