• Title/Summary/Keyword: best-it sphere

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Adaptive K-best Sphere Decoding Algorithm Using the Characteristics of Path Metric (Path Metric의 특성을 이용한 적응형 K-best Sphere Decoding 기법)

  • Kim, Bong-Seok;Choi, Kwon-Hue
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.11A
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    • pp.862-869
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    • 2009
  • We propose a new adaptive K-best Sphere Decoding (SD) algorithm for Multiple Input Multiple Output (MIMO) systems where the number of survivor paths, K is changed based on the characteristics of path metrics which contain the instantaneous channel condition. In order to overcome a major drawback of Maximum Likelihood Detection (MLD) which exponentially increases the computational complexity with the number of transmit antennas, the conventional adaptive K-best SD algorithms which achieve near to MLD performance have been proposed. However, they still have redundant computation complexity since they only employ the channel fading gain as a channel condition indicator without instantaneous Signal to Noise Ratio (SNR) information. hi order to complement this drawback, the proposed algorithm use the characteristics of path metrics as a simple channel indicator. It is found that the ratio of the minimum path metric to the other path metrics reflects SNR information as well as channel fading gain. By adaptively changing K based on this ratio, the proposed algorithm more effectively reduce the computation complexity compared to the conventional K-best algorithms which achieve same performance.

Development of Micro-hemisphere Flexible PDMS Film for Enhancing Light Extraction in Organic Light-emitting Devices (유기발광소자의 광추출 향상을 위한 미세 반구형 유연 필름 연구)

  • Baek, Dong-Hyun;Bae, Eun-Jeong;Maeng, Hyeongkyu;Shin, Ji Soo;Park, Young Wook
    • Journal of the Semiconductor & Display Technology
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    • v.21 no.4
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    • pp.1-5
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    • 2022
  • We presented a micro hemi-sphere structure flexible film to improve the external quantum efficiency (EQE) in OLEDs. The micro hemi-sphere flexible film was fabricated with breath figure (BF) method and replica process. At 45 mg/mL of concentration, the size of the hemi-spheres was approximately 6.2 ㎛ were obtained which are the most circular shape. So, it was possible to yield the best performance with an improvement of 33 % in the EQE and the widest viewing angle ranging from 0° to 70°. As a result, the hemi-sphere film's size and distribution seem to play important roles in enhancing the EQE in OLEDs. Furthermore, the flexible hemi-sphere film based on polymeric materials could offer an effective, large-scale, mass-produced product and a simple process and approach to achieve high efficiency in flexible OLEDs.

An Efficient K-BEST Lattice Decoding Algorithm Robust to Error Propagation for MIMO Systems (다중 송수신 안테나 시스템 기반에서 오차 전달을 고려한 효율적인 K-BEST 복호화 알고리듬)

  • Lee Sungho;Shin Myeongcheol;Seo Jeongtae;Lee Chungyong
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.42 no.7 s.337
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    • pp.71-78
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    • 2005
  • A K-Best algerian is known as optimal for implementing the maximum-likelihood detector (MLD), since it has a fixed maximum complexity compared with the sphere decoding or the maximum-likelihood decoding algorithm. However the computational complexity of the K-Best algrithm is still prohibitively high for practical applications when K is large enough. If small value of K is used, the maximum complexity decreases but error flooring at high SNR is caused by error propagation. In this paper, a K-reduction scheme, which reduces K according to each search level, is proposed to solve error propagation problems. Simulations showed that the proposed scheme provides the improved performance in the bit error rate and also reduces the average complexity compared with the conventional scheme.

Optimal Shape of $\mu$BGA Solder Joints and Thermal Fatigue Life ($\mu$BGA 솔더접합부의 형상과 수명평가)

  • 신영의;황성진;김종민
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • 2002.05a
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    • pp.117-120
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    • 2002
  • In this paper, several methods to predict the solder joint shape are studied. Although there are various methods to predict the solder joint shape, such as truncated sphere method, force-bal tranced analytical solution, and energy-based methods like surface evolver developed by Ken Brakke, we calculate solder joint shape of $\mu$BGA by two solder joint shape prediction methods(truncated sphere method and surface evolver) and then compare results of each method. The results in dicate that two methods can accurately predict the solder joint shape in an accurate range. After that, we calculate reliability solder joint shape under thermal cycle test by FEA program ANSYS. As a result, it could be found that optimal solder joint shape calculated by solder joint prediction method has best reliability in thermal cycle test.

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A Study on the Optimal Shape Prediction of $\mu$BGA Solder Joints ($\mu$BGA 솔더 접합부의 최적 형상 예측에 관한 연구)

  • 신영의;지시헌;후지모토고조;김종민
    • Journal of the Microelectronics and Packaging Society
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    • v.8 no.4
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    • pp.35-41
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    • 2001
  • In this paper, several methods to predict the solder joint shape are studied. Although there are various methods to predict the solder joint shape, such as truncated sphere method. force-balanced analytical solution, and energy-based methods like surface evolver developed by Ken Brakke, we calculate solder joint shape of $\mu$BGA by two solder joint shape prediction methods(truncated sphere method and surfaceevolver) and then compare results of each method. The results indicate that two methods can accurately predict the solder Joint shape in an accurate range. After that, we calculate reliability solder joint shape under thermal cycle test by FEA program ANSYS(version 5.62). As a result, it could be found that optimal solder joint shape calculated by solder joint prediction method has best reliability in thermal cycle test.

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The Hope of the Stroke Patients (뇌졸중환자의 희망)

  • 김이순
    • Journal of Korean Academy of Nursing
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    • v.27 no.1
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    • pp.212-227
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    • 1997
  • Cerebrovascular diseases in Korea is an important health problem since mortality and mobidity have been increased rapidly. It marked the 2nd cause of specific death rates in 1993. The stroke causes physical function disorder due to hemiparalysis and emotional disorder, and stroke patients experience helplessness, powerlessness. sense of alienation and loss of hope. These feelings make the rehabilitation difficult because they lose the will of life. The subjects of the study were seven citizens who live in Pusan, are over 50 years old and belong to low income-level. The data were collected from Jan. to Sep. 1995. The researcher as a caregiver and volunteer made confidence of them and asked for their agreement on the purpose of the study. The subjects expressed their experience as openheartedly as possible. The analysis of the data was made through the phenomenological analytic method suggested by Giorgi, which is as follows ; as an unit of description which include the subject' expressions and the researcher's observation, it is examined the theme that express the hope experience with the subject's language(underlining), and the focal meanings are identified. The focal meaning is the crystalization of the theme, which is written in the language of the researcher. After intergrating the focal meaning and make the situated structural description as the meaning of the hope experience identified on each subject's point. After intergrating the situated structural description and make the general structural description as the meaning of the hope experience identified on total subject's point then the systemizing of the structure of the hope experienced phenomena and the flowing of the conciousness was researched. The conclusions of this study was as follows : The ten sources of hope which the subjects experienced were sorted as under 〈mutual relations to others : spouse, children, relatives, fellow believer. health professioner. associate patient group〉, 〈spiritual dependence〉. 〈recovery of physical function〉. 〈rumination of the past life〉, 〈expectation of the future〉. 〈economic power〉, 〈belief〉, 〈ability〉. 〈spontaneous participation〉 and 〈recovery of roles〉. Their hope was spoken out by the following two kinds of linguistics. First. the hope was expressed in the affirmative expression as follows : 〈 to be dependable〉, 〈to make efforts〉, 〈to keep under control〉, 〈to desire〉, 〈to be pleasant〉, 〈to be peaceful〉, 〈to be grateful〉, 〈to give help〉, 〈self-confidence. Courage〉, 〈to be happy〉, 〈to satisfy oneself〉, 〈to share with others〉, 〈to understand〉 and 〈to be affected, be impressed〉 Second, the hope was expressed in the negative on pression as under : 〈to be distressed〉, 〈to be uneasy〉, 〈to be sorry, be unsatisfied〉 〈despair〉, 〈to abandon〉, 〈to be fearful〉, 〈to suffer〉, 〈to bear a burden〉 〈to be confused〉, 〈to be solitary〉, 〈chest trouble〉, 〈to feel heavy〉 〈grief〉, 〈to be daunted〉, 〈to get angry〉, 〈to be uncomfortable〉, 〈to have something regretable〉 and 〈to feel guilty〉. And their hope was expressed by the following four behavioral expressions : 〈physical sphere〉, 〈psychological sphere〉, 〈social support sphere〉 and 〈spiritual sphere〉. The reaction patterns of their hope experience appeared in the following 4 coping method : 〈conquest type〉, 〈dependence type〉, 〈adaptation type〉 and 〈fate type〉. Finally, in the hope structure the sense of certainty don't always coexict with the sense of uncertainty, When the stroke patients try to search for the best quality of life, the senses of certainty and uncertainty make a continual cyclic system in the hope structure.

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Design of Passive-Type Radar Reflector

  • Yim, Jeong-Bin;Kim, Woo-Suk
    • Journal of Navigation and Port Research
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    • v.27 no.3
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    • pp.267-272
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    • 2003
  • This paper describes design method of Passive-type Radar Reflector (PRR) which is to provide the requirement of newly revised 2000 SOLAS regulations on the Radar Reflector. The main target of this work is to find the optimum shape of a radar target having large Radar Cross Section (RCS). Through the RCS analysis based on the theoretical approach, two kinds of PRR models, RRR-F model for use in fisheries and PRR-S model for use in small sized ship, are designed and discussed their RCS performance. RCS measurement tests for the various sized samples are carried out in an anechoic chamber. As evaluation results it was clearly shown that the conventional sphere-type shows optimum shape in case of PRR-S, while the cylinder-type which consists of large sized corner clusters or zig-zag flat plats gives best performance in case of PRR-F.

E-Governmentfor Efficient Governance: Instructive Cooperation of the Republic of Belarus and the Republic of Korea in the Sphere of e-Government

  • Tchouechov, Viktor I.;Zhmakina, Tatiana V.
    • Korea Multimedia Society
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    • v.22 no.1
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    • pp.26-33
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    • 2018
  • The transformation of the processes of governance using the Information and Communication Technologies is aimed at bringing in faster and transparent service delivery, accountability, information sharing and people participation in the decision-making and government processes. The implementation of e-Government requires a comprehensive strategy that is not only sensitive to existing political and economic conditions and realities but is also benchmarked on global best practices. The article reviews the handbook E-Government and Governance Efficiency that provides an insight to research that is being undertaken in the e-Government area, gives an in-depth understanding of critical issues involved in e-Government, and provides expert opinion and recommendations for the Republic of Belarus to augment its potential. It studies the Korean experience on e-Government with special focus on such concepts as e-Government benchmarking, mGovernment, Smart Government and u-Government.

3D Magnetic Analysis of Permanent Magnets in Spherical Configuration

  • Oner, Yusuf;Kesler, Selami
    • Journal of Electrical Engineering and Technology
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    • v.11 no.1
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    • pp.93-99
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    • 2016
  • The present study aims to increase the amount of surface flux by changing the magnetic directions of a spherical magnet (NdFeB) consisting of four poles. For this purpose, the magnetic directions of quartile spherical slices constituting the spherical magnet are manipulated and their three-dimensional analyses are carried out by using finite-element method via Maxwell environment. The analysis of the magnetic quartile spheres with four different magnetic directions are compared to the each other, and then the quartile sphere with the best surface flux distribution is suggested for rotor structure. It is clear emphasized that the induced torque of the spherical motor, in which such a rotor is used, will be improved as well.

Influence of the Kinds and the Content of Expansive Additive on the Properties of Shrinkage of High Performance Concrete (고성능 콘크리트의 수축특성에 미치는 팽창재 종류 및 혼입률의 영향)

  • 배정렬;홍상희;고경택;김성욱;한천구
    • Proceedings of the Korea Concrete Institute Conference
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    • 2003.05a
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    • pp.349-354
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    • 2003
  • The objective of this paper is to investigate the length change of high performance concrete using expansive additives to reduce autogenous shrinkage and drying shrinkage. The kinds and the contents of expansive additives are varied. The expansive additives are used made from Japan(CSA type;JEA), China(CSA type;CEA) and Korea(gypsum type; KEA), respectively. According to results, remarkable variations of the properties at fresh concrete are not found with dosage of expansive additives. For compressive strength, it decreases about 6-10% with expansive additives of 10%. Autogenous shrinkage decreases about 32%, and drying shrinkage does about 35%, respectively, with expansive additives of 5%, and about 68% and about 55%, with expansive additives of 10%. Accordingly, expansive additives demand requires 10% by cement weight in order to reduce shrinkage of high performance concrete more effectively in the sphere of this study, and JEA shows the best shrinkage reducing performance among the tested expansive additives.

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