• 한국소음진동공학회논문집
• /
• 제12권6호
• /
• pp.461-468
• /
• 2002

Computer simulation is essential to design the suspension elements of railway vehicle. By computer simulation, engineers can assess the feasibility of the given design factors and change them to get a better design. But if one wishes to perform complex analysis on the simulation, such as railway vehicle dynamic, the computational time can become overwhelming. Therefore, many researchers have used a surrogate model that has a regression model performed on a data sampling of the simulation. In general, metamodels(surrogate model) take the form y($\chi$)＝f($\chi$)＋$\varepsilon$, where y($\chi$) is the true output, f($\chi$) is the metamodel output, and is the error. In this paper, a second order polynomial equation is used as the RSM(response surface model) for high speed train that have twenty-nine design variables and forty-six responses. After the RSM is constructed, multi-objective optimal solutions are achieved by using a nonlinear programming method called VMM(variable matric method) This paper shows that the RSM is a very efficient model to solve the complex optimization problem.

• 제어로봇시스템학회논문지
• /
• 제17권6호
• /
• pp.546-551
• /
• 2011

Tilt sensor is required to control the attitude of the biped robot when it walks on an uneven terrain. Vision sensor, which is used for recognizing human or detecting obstacles, can be used as a tilt angle sensor by comparing current image and reference image. However, vision sensor alone has a lot of technological limitations to control biped robot such as low sampling frequency and estimation time delay. In order to verify limitations of vision sensor, experimental setup of an inverted pendulum, which represents pitch motion of the walking or running robot, is used and it is proved that only vision sensor cannot control an inverted pendulum mainly because of the time delay. In this paper, to overcome limitations of vision sensor, Kalman filter for the multi-rate sensor fusion algorithm is applied with low-quality gyro sensor. It solves limitations of the vision sensor as well as eliminates drift of gyro sensor. Through the experiment of an inverted pendulum control, it is found that the tilt estimation performance of fusion sensor is greatly improved enough to control the attitude of an inverted pendulum.

• 대한전자공학회논문지SD
• /
• 제44권11호
• /
• pp.1-8
• /
• 2007

본 논문에서는, 무선 통신 응용을 위한 광대역 연속시간 시그마-델타 모듈레이터를 130nm CMOS공정으로 구현하였다. 제안된 양자화 레벨을 효율적으로 조절할 수 있는 적응성 양자화기를 사용하여, 작은 크기의 입력에 대해서 SNR의 이득을 볼 수 있었다. 모듈레이터는 전력 소모를 줄이기 위해 2차 루프 필터로 구성되어 있고, 지터에 의한 영향을 줄이고 높은 선형성을 보장하기 위해 4 비트 양자화기, DAC를 사용하였다. 설계된 회로는 320MHz 샘플링 주파수에서 동작하며 10MHz 입력 대역에서 30mW의 전력을 소모하고 최대 SNR 51.36dB를 얻었다.

• 한국통신학회논문지
• /
• 제29권3C호
• /
• pp.419-425
• /
• 2004

본 논문은 카메라로 찍은 투사 사영(Perspective Projection)의 한 영상으로부터 물체의 크기와 위치를 계산하기 위해서 3 개의 소실 점만을 사용해서 계산하는 새로운 방법을 제안한다. 우리의 접근 방법은 투사 사영의 영상으로부터 초점 거리(Focal Length), 회전 행렬(Rotation Matrix) 등의 정보들 없이 3개의 소실 점만을 가지고 계산하는 방법이다. 물체는 꼭지점(vertices)의 좌표가 크기 벡터 v 의 선형 함수로서 표현할 수 있는 다각형으로써 모델이 된다는 것을 가정한다. 이 재구성의 입력은 영상에서 특징 점과 모델에서 특징 점 사이 대응점의 집합으로 표현할 수 있다. 이 매개 변수 모델의 각각 크기를 최적화하기 위해서, 재구성의 최적화는 동일하게 매개 변수 공간을 샘플링에 의한 최적화기에 대하여 다중 시작점(multiple starting points)을 발생하는 다중 시작(multi-start) 방법을 가지는 표준 비선형 최적화 기법을 효과적으로 해결할 수가 있다.

• 한국병원경영학회지
• /
• 제3권1호
• /
• pp.192-218
• /
• 1998

This study is the positive one about the influence which the characteristics of medical consumers' perceived words-transmission information exercises on its acceptance level and its activities. The aim of this study was to investigate how the characteristics-reliability of perceived information, its directionity, and its availability-had an influence on the acceptance level and activities of words-transmission information. For the purpose of that aim, the positive research by questionnaire was applied. In addition, to collect necessary data, investigation was performed about 20 days from July 1st, 1938 to July 20th, 1938. As for the respondents' sampling in sample planning, the method of Simple Random Sampling was used laying stress on patients or their responsible person aged over 20s in second and third medical institutions. And the collected sample were 230 people. Of these, However, the number of sample used actually for this study analysis was 211 except 19 people who responded unfaithfully. The analysis of the data collected by the abovesaid investigation used SPSS/PC statistical package. The study result to have proved the hypothesis by experiment is as follows. First, as the result of having analysed the influence relations on the acceptance level and activities of words-transmission information among the factors of reliability about medical consumers' perceived information, I found that 'specialty' had an affirmative effect and there was a significant effect relations. Second, as the result of having made a multi-regression analysis of the effect relations on the acceptance level and activities of words-transmission information of the factors of directionity on medical consumers' perceived information, 'reliablity' was found as having a significant effect on the acceptance of words-transmission information. Third, 'importantness' was revealed as having a significant effect on the words-transmission activities in the acceptance level and activities of words-transmission information among the factors of reliability on medical consumers' perceived information. Fourth. for medical consumers there was a statistical correlation between the acceptance level and activities of words-transmission information. Therefore, words-transmission communication will be very useful for hospital promotion programs having a limited advertising ability in business. Especially, I suggest that a person in charge of his/her hospital marketing should not only excavate a source of words-transmission communication in order to arrive effectively at sampling market, but also use a marketing mix suitable to that The test result shows that the unsatisfied patients over their hospital treatment tend to be more stronger in transmitting words to the other positive minded patients than the satisfied ones. Therefore, all relating representatives in hospital should concentrate their energies on decreasing or eliminating these unwanted results.

• 환경영향평가
• /
• 제18권3호
• /
• pp.151-160
• /
• 2009

In order to use fundamental data for conservation of species diversity and stream health with dam development, fish investigation in up- and downstream of Pyeonglim Dam was seasonally conducted in 2007~2008. In addition, data of water qualities, investigated for environmental impact assessment, were used to determine a water quality standard level in Pyeonglim Stream, and it revealed that water environment condition was good in the stream. During the study period, a total number of fish caught from the 4 study sites was 5,449 representing 9 families 25 species, and there were 8 Korean endemic species (32.0%) including Rhodeus uyekii, Squalidus gracilis majimae, and Microphysogobio yaluensis. Two species of Zacco temminckii (37.5%) and Zacco platypus (26.3%) were dominant and subdominant in all sites. There were few individuals of the $2^{nd}$-class endangered species (Sand lamprey, Lampetra reissneri) and the introduced species (Bluegill, Lepomis macrochirus), found in the upstream of the dam. and further investigation for conservation of the endangered species and for prevention of the introduced species is needed in future. With fish fauna and multi-metric health assessment model in each sampling attempt, index of biotic integrity(IBI) was evaluated and it resulted mostly in good(26~35) and excellent(36~40) condition in all sites. The results indicate that it is very important to study not only environmental impact assessment with fish composition but also stream health assessment in order to conserve healthy aquatic ecosystem.

• 한국운동역학회지
• /
• 제15권3호
• /
• pp.143-152
• /
• 2005

The purpose of this study was to predict the failure or success of the Snatch-lifting trial as a consequence of the stand-up phase simulated in Kane's equation of motion that was effective for the dynamic analysis of multi-segment. This experiment was a case study in which one male athlete (age: 23yrs, height: 154.4cm, weight: 64.5kg) from K University was selected The system of a simulation included a multi-segment system that had one degree of freedom and one generalized coordinate for the shank segment angle. The reference frame was fixed by the Nonlinear Trans formation (NLT) method in order to set up a fixed Cartesian coordinate system in space. A weightlifter lifted a 90kg-barbell that was 75% of subject's maximum lifting capability (120kg). For this study, six cameras (Qualisys Proreflex MCU240s) and two force-plates (Kistler 9286AAs) were used for collecting data. The motion tracks of 11 land markers were attached on the major joints of the body and barbell. The sampling rates of cameras and force-plates were set up 100Hz and 1000Hz, respectively. Data were processed via the Qualisys Track manager (QTM) software. Landmark positions and force-plate amplitudes were simultaneously integrated by Qualisys system The coordinate data were filtered using a fourth-order Butterworth low pass filtering with an estimated optimum cut-off frequency of 9Hz calculated with Andrew & Yu's formula. The input data of the model were derived from experimental data processed in Matlab6.5 and the solution of a model made in Kane's method was solved in Matematica5.0. The conclusions were as follows; 1. The torque motor of the shank with 246Nm from this experiment could lift a maximum barbell weight (158.98kg) which was about 246 times as much as subject's body weight (64.5kg). 2. The torque motor with 166.5 Nm, simulated by angular displacement of the shank matched to the experimental result, could lift a maximum barbell weight (90kg) which was about 1.4 times as much as subject's body weight (64.5kg). 3. Comparing subject's maximum barbell weight (120kg) with a modeling maximum barbell weight (155.51kg) and with an experimental maximum barbell weight (90kg), the differences between these were about +35.7kg and -30kg. These results strongly suggest that if the maximum barbell weight is decided, coaches will be able to provide further knowledge and information to weightlifters for the performance improvement and then prevent injuries from training of weightlifters. It hopes to apply Kane's method to other sports skill as well as weightlifting to simulate its motion in the future study.

• 전자공학회논문지
• /
• 제53권7호
• /
• pp.39-46
• /
• 2016

본 논문에서는 음성 신호의 디지털 데이타 변환을 위한 인버터와 1.5비트 비교기를 이용한 CMOS 3차 델타-시그마 변조기를 설계하였다. 제안하는 3차 델타-시그마 변환기는 연산증폭기 대신에 1.5비트 비교기를 이용한 멀티비트 구조로 낮은 OSR에서 단일비트 4차 델타-시그마 변조기 대비 높은 신호대 잡음비를 확보하고 인버터 기반 적분기를 사용하여 소모 전력을 최소화 시키며 인버터 기반 적분기 회로를 아날로그 덧셈기로 이용함으로써 전력소모를 감소시키고 회로구조를 단순화 시켰다. 제안한 델타-시그마 변조기는 0.18um CMOS 표준 공정을 통해 제작되었으며, 전체 칩면적은 $0.36mm^2$으로 설계되었다. 제작된 칩의 측정 결과 아날로그 회로는 공급전압 0.8V에서 $28.8{\mu}W$, 디지털 회로는 공급전압 1.8V에서 $66.6{\mu}W$로 총 $95.4{\mu}W$의 전력소모가 측정되었다. 델타-시그마 변조기의 동작주파수 2.56MHz, OSR 64배의 조건에서 2.5kHz의 입력 정현파 신호를 인가하였을 때 SNDR은 80.7 dB, 유효비트수는 13.1 비트, 동적범위는 86.1 dB로 측정되었다. 측정결과로부터 FOM(Walden)은 269 fJ/step, FOM(Schreier)는 169.3 dB로 계산되었다.

• 수산경영론집
• /
• 제21권2호
• /
• pp.55-84
• /
• 1990

The objective of this study is to develop an inventory model for the inventory management of a stocking point which sells processed fisheries products. The study, first of all, sets up fisheries processing companies, food companies, apparel companies, pharmaceutical companies and electronic and electrical companies as a population. Then, a comparative study is empirically applied to obtain the inventory characteristics of final products by industry through a survey of a sample selected by a random sampling procedure. The major inventory characteristics of processed fisheries products obtained from the above analysis can be summarized as follows : 1) The major demand characteristics of processed fisheries products is to have wide seasonal fluctuations because the supply of raw materials (i.e., fisheries products) heavily depends on the productive capacity of nature. 2) It has found that fisheries processing companies are the worst in inventory management among the various industries selected in the sample. However, the self-rating of inventory management system by inventory managers of companies shows that the fisheries processing companies are relatively higher than the other companies. 3) The portion of inventory holding cost out of inventory relevant cost is very high for processed fisheries products compared with final products of the other industries. 4) Processed fisheries products are distributed to final consumers through roughly two distribution echelons and take a parallel type inventory system for their distribution structure. In order to develop an inventory model which reflects the inventory characteristics of processed fisheries products mentioned in the above, an inventory model with partial backorders is developed under the situation of stochastic lead time under the consideration of the inventory characteristics of processed fisheries products and then an iterative solution method is provided for the model. Then this study analyzes sensitivity for the standard deviation of lead time in the model by numerical examples.

• Asian Pacific Journal of Cancer Prevention
• /
• 제14권6호
• /
• pp.3689-3698
• /
• 2013

Breast cancer is the most common and leading cause of cancer mortality among Malaysian women. Despite good survival rates, the diagnosis of cancer still invokes the feeling of stress, fear and uncertainty. Because very little is known about the experiences of Malaysian women with breast cancer, a qualitative study using semi-structured interviews to explore the lived experience of newly diagnosed breast cancer. Using a purposive sampling method, 20 Malaysian women newly diagnosed with breast cancer, including Malays (n=10) and Chinese (n=10) were recruited in two main public hospitals in Kelantan. Similarities and divergence in women's experience were identified through thematic analysis of interview transcripts. Three themes emerged from the data: uncertainty experience of the illness, transition process and fatalistic view of breast cancer. In many ways, these findings were parallel with previous studies, suggesting that the experience of breast cancer is to a certain extent similar among women newly diagnosed with breast cancer. This study adds to the sparse literature concerning the experience of illness following breast cancer diagnosis among the Malays and Chinese. More importantly, this study addressed areas that were previously lacking, specifically in depth information on breast cancer experience from a developing country with a multi-ethnic population. The results of this investigation provide preliminary information to healthcare professionals on the impact of illness and cultural influence on survivorship to plan for appropriate education and supportive programme in order to meet the needs of breast cancer women more effectively.