• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.34 no.2
• /
• pp.71-75
• /
• 2021

Despite the development of computational resources, the need to analyze models is increasing. The size of model has been increased to analyze the entire structure more accurately and precisely. As the analysis model becomes larger and more complex, the computation time increases exponentially. Various industries use many structures that have repeated patterns. We focus on these structures with repeated patterns and propose a dynamic analysis method to efficiently calculate these repeated structures. To devise an efficient method for repeated structures, the substructuring scheme and the degree of freedom-based reduction method are used in this study. We modify the existing reduction method in consideration of the characteristics of the repeating structure. In the proposed method, the entire structure was expressed as a combination of substructures, where each substructure was represented as an unit cell of repeated structures. The substructures were condensed and assembled using the substructuring scheme and the modified condensation method. Finally, numerical examples were demonstrated to verify the efficiency and accuracy of proposed method.

• Journal of Platform Technology
• /
• v.11 no.6
• /
• pp.89-105
• /
• 2023

With the development of information technology, most of the information has been converted into digital information, leading to the Big Data era. The demand for search platform has increased to enhance accessibility and usability of information in the databases. Big data search software platforms consist of two main components: (1) an indexing component to generate and store data indices for a fast and efficient data search and (2) a searching component to look up the given data fast. As an amount of data has explosively increased, data indexing performance has become a key performance bottleneck of big data search platforms. Though many companies adopted big data search platforms, relatively little research has been made to improve indexing performance. This research study employs Elasticsearch platform, one of the most famous enterprise big data search platforms, and builds physical clusters of 3 nodes to investigate optimal indexing performance configurations. Our comprehensive experiments and studies demonstrate that the proposed optimal Elasticsearch configuration achieves high indexing performance by an average of 3.13 times.

• Childhood Kidney Diseases
• /
• v.6 no.2
• /
• pp.198-208
• /
• 2002

Purpose : There is no scientific basis for an immunization policy for children with renal disease who have increased risk of infection in Korea. As an initial step in approaching this problem, this survey of pediatric nephrologists was undertaken to determine the current recommendations of practicing pediatric nephrologists Methods : Questionnaires were sent to the members of Korean Society of Pediatric Nephrology via mail and E-mail. The questionnaire was designed to obtain information about the immunization practice of basic vaccination schedule for nephrotic syndrome, the side effects after vaccination and the immunization practice about recommended vaccines for children with renal disease. Results : Questionnaires were sent to 56 pediatric nephrologists. 35 replies were received (response rate: 62.5%). Almost of the respondents (82.8%) reported practicing at university hospital. All respondents reported modified vaccination schedule. 65.7% of the respondents immunized nephrotic children with live vaccines some time later after discontinuation of corticosteroids treatment and 57.1% of respondents immunized them with killed vaccines during medication of low doses of corticosteroids. Respondents experienced relapse of nephrotic syndrome after vaccination are nine, lack of vaccine efficacy are three and infection by organisms of live vaccines are two. 71.4% of respondents reported vaccinating children with renal disease for hepatitis B, pneumococcus and influenza during medication of low doses of corticosteroids. But There is few difference of the rates of respondents vaccinating them for Hemophilus influenzae type b between during medication of low doses of corticosteroids and after discontinuation of corticosteroids treatment (45.7% us 42.9%). Almost of respondents reported vaccinating renal failure children without immunosuppression for hepatitis B, pneumococcus, influenza and H. influenzae type b ($54.3{\sim}77.1%$). Conclusion : Pediatric nephrologists practiced modifying vaccination schedules for children with renal disease in Korea and there was variation according to the progression of disease and the doses of corticosteroids. It is necessary to establish the immunization guideline for children with renal disease through the prospective studies.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.21 no.5
• /
• pp.486-493
• /
• 2010

This article introduces a novel ultra wideband(UWB) bandpass filter(BPF) with sharp roll-off characteristics in stripline structure. The UWB characteristic is basically obtained from capacitive coupled cross resonator. The resonator has ${\lambda}/2$ length. And at the center of the resonator, two stubs are loaded, one is a ${\lambda}/8$ short-circuited stub and the other is a ${\lambda}/8$ open-circuited stub. The two stubs provide two attenuation poles at lower and upper cutoff frequencies. For input and output lines, two identical capacitively coupled lines have been installed to suppress the unwanted signals in the lower and upper stopbands. The filter has been designed for the U.S. UWB band(3.1~10.6 GHz) with two transmission zeros at 2.4 and 11.1 GHz. The filter has been realized with Low Temperature Core-fired Ceramic(LTCC) green tape which has the dielectric constant of 7.8. Measurement results agree well with HFSS simulation results. Insertion loss less than 0.7 dB and return loss better than 14 dB in the pass band have been measured. The group delay in the center frequency is 0.27 ns and the group delay variation within pass band is less than 0.5 ns. The size of the filter is $6{\times}18{\times}0.6\;mm^3$.

• Journal of Sericultural and Entomological Science
• /
• v.15 no.1
• /
• pp.15-25
• /
• 1973

The author studied the applicability of Furazolidone to the silkworm rearing industry as a useful remedy for certain silkworm diseases, at the silkworm rearing house of the college of agriculture, Seoul national university, during both the spring and the autumn silkworm rearing season of 1972. Discovering the fact that Furazolidone, when put on the mulberry leaves in a powdered form, is eaten along with the leaves by silkworms and thus the systematic administration of Furazolidone to silkworms is possible, the experimenter carried on a series of experiments (1. determining the in vitro antibacterial activity of Furazolidone to four pathogens of silkworm diseases-Bacillus thuringiensis, Aspergillus oryzae, Aspergillus flavus, and Isaria farinosa, 2. observing the prophylactic and therapeutic effect of Furazolidone against the experimental flacherie caused by inoculation of B. thuringiensis, and 3. examining the toxicity of Furazolidone to silkworm larvae). As the results of the experiments the investigator found out the fundamental fact that Furazolidone exerts a good prophylactic and therapeutic effect against flacherie which is the most common and important silkworm disease: Furazolidone, in in vitro test, inhibited completely the growth of B. thuringiensis, the pathogen of bacterial flacherie, at the concentration of 1 ${\mu}$g/mι. with the tube method and at the concentration of 5 ${\mu}$g/mι. with the plate method, and the drug showed an excellent prophylactic effect and a considerably good therapeutic effect, depending on the time of administration, on the 5th instar silkworms inoculated B. thuringiensis, at the tentative dose of 150mg. per 10 silkworms administered once a day for 2 days. For the practical administration of Furazolidone against flacherie, the dose, the time and duration of administration, and the form of preparation, will be investigated more closely.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.13 no.5
• /
• pp.30-34
• /
• 1976

A system that can discriminate monosyliables automatically from sequential input of Korean character's data without space codes is proposed. Korean characters are synthesized by two to seven elements out of twenty four basic elements. Three thousands Korean characters are formalized into thirty character forms discriminates monosyllable automatically by detecting seven form features and character length. In this result, this system, compared with the input method with space codes which have been used to separate each syllable, can save about 25% of the memory capacity of computer and improves about 30% of the processing speed of Korean characters.

• Proceedings of the Korean Information Science Society Conference
• /
• 2005.11a
• /
• pp.379-381
• /
• 2005

Ad hoc 네트워크에서 노드의 한정된 에너지 용량은 개설 경로의 수명과 안정성에 많은 영향을 미치는 요소이다. 따라서 이러한 에너지 한계를 극복하기 위한 다양한 power-aware 라우팅 프로토콜들이 네트워크 계층에서 제안되고 있으며, 이들 라우팅 프로토콜들은 기본적으로 노드의 배터리 잔량 에너지와 전송 전력량을 경로 탐색 과정에서 반영한다. 본 논문에서는 기존의 power-aware 라우팅 프로토콜보다 개설 경로의 동작시간을 높이고 전체 네트워크의 부하균등을 이를 수 있도록 하는 새로운 라우팅 프로토콜을 제안하며 TPR(Traffic load based power-aware routing protocol)로 명명한다. TPR은 NS-2를 이용한 성능 평가를 통해 전체 네트워크의 부하 균등과 개설 경로의 수면, 안정성 측면에서의 개선점을 확인한다.

• Proceedings of the Korean Information Science Society Conference
• /
• 2005.11a
• /
• pp.712-714
• /
• 2005

본 논문은 효율적인 점 기반 렌더링(Point-based Rendering)을 위해 확장 이차 오류 척도(Quadric Error Metrics) 기법을 이용하는 간략화 알고리즘을 제안한다. 점 기반 렌더링의 기본 개념은 자유곡면을 메쉬와 같은 연결정보 없이 직접 점들로 표현하고, 렌더링하는 것이다. 확장 이차 오류 척도 기법은 메쉬를 간략화 하는데 있어 기하 정보뿐만 아니라 색상, 텍스쳐 좌표 정보까지 고려하여 간략화 하는 알고리즘이다. 이 연구는 3차원 점 데이터로부터 복원한 폴리곤 메쉬 모델로부터 효율적인 점 기반 렌더링(Point-based Rendering)을 위해 기하 정보 및 색상 정보까지 고려하여 원본 점 데이터를 간략화 하는 저용량의 효율적인 점 기반 렌더링 알고리즘을 제안하고, GPU 기반 렌더링 결과를 보였다.

• JOURNAL OF ELECTRICAL WORLD
• /
• s.393
• /
• pp.51-57
• /
• 2009

최근, 국가적인 차원에서 추진되고 있는 풍력발전, 태양광발전 등과 같은 신 에너지전원(분산전원)은 기존의 전원에 비하여 소규모 전원인 관계로 주로 수용가에 가까운 배전계통에 도입되어지고 있으며, 그 특성상 배전계통과 연계하여 운전함으로써 보다 안정된 전력의 확보 및 전력설비의 효율적인 활용, 자원의 효율적인 이용 등의 이점을 얻을 수 있다. 한편, 태양광과 풍력 등의 자연에너지를 이용한 분산전원은 일정한 출력을 내는 기존의 전원보다 기후나 온도, 지형적인 영향을 많이 받는 간헐적인 전원이의로, 이들이 도입된 배전계통은 기존의 단 방향 공급형태의 배전계통과는 달리 부하와 전원이 혼재되어 운용되는 형태로 된다. 분산전원이 연계된 배전계통의 경우에는 분산전원의 출력 용량 여부에 따라 양방향의 전력조류가 발생할 가능성이 있어, 계통운용상 여러 가지 문제점이 야기될 수 있다. 따라서 본 연구에서는 분산전원 연계에 따른 보호협조 기본 방안과 부하절체 운전과 변압기결선에 따른 보호협조 방안 등에 대한 알고리즘을 제시하였다. 또한, 이론적인 계산법(대칭좌표법)에 의하여 실 계통에서의 양방향 보호협조에 관련된 문제점을 분석하고, 해결방안을 제시하였다.

• 전기의세계
• /
• v.38 no.6
• /
• pp.12-18
• /
• 1989

한국형 고속전철을 고려하는데 있어서 위에서의 기술적인 측면보다도 오히려 수송용량, 경제성, 운영방식의 측면에서 더 많은 비중을 두고 검토해야 하는지도 모른다. 그러한 측면에서 한국형 고속전철은 한국의 지형조건, 경부간의 연변인구, 현경부선의 장래, 고속전철의 운영방식, 한국철도의 기술수준 등을 고려하지 않으면 안되고 한국형이어야 한다. 한국형 고속전철은 1. 경부간 고속전철의 거리는 380Km정도이므로 2000년대의 국민 일인당 시간가치를 기준으로 최고속도를 결정하여야 하고 표정속도는 190Km/h이상이어야 한다. 2. 고속화를 위한 필수조건인 차량의 축중을 17톤 이하로 제한하여야 하고 기존의 철도차량이 고속전철선에 야간열차등으로 투입되더라도 이 원칙은 유지되어야 한다. 3. 수송능력을 확보하기 위하여 열차편성당 좌석수는 800석 이하로 확보되어야 한다. 4. 기존선에서의 연장운행이 불가피하므로 기존선의 차량한계 내에서 안전하게 운행될 수 있어야 하고 전력공급은 기존선 방식인 A/C25KV, 60HZ의 사용이 불가피하다. 5. 고속전철의 건설비용, 차량의 제작비, 기술이전도, 국산화율 등을 고려한 시스템이어야 한다. 한국형 고속전철은 위의 기본원칙을 최소한 만조시킬 수 있는 시스템이어야 한다.