• The Transactions of the Korean Institute of Power Electronics
• /
• v.11 no.1
• /
• pp.46-55
• /
• 2006

This paper presents the control method for the hybrid actuator comprising a DC motor and an MR brake. Generally, a DC motor as an active actuator has a small power to weight ratio and goes unstable with higher force control gain due to its saturation limit. In order to cope with this instability and make the transparency higher, this paper proposes a hybrid actuator which consists of a DC motor and an MR brake as a passive actuator and its force control method based on network theory. A DC motor actively produces the output corresponding to the signs of the input currents. On the other hand, an MR brake passively resists against the external load independent of the sign changes of the input currents. This characteristics is widely known as 'passive' This paper suggests a force control method based on passivity concept in network theory for the hybrid actuator and verified its performance and stability through the experiments.

• Food Science of Animal Resources
• /
• v.24 no.4
• /
• pp.349-354
• /
• 2004

Stress-susceptible pigs have been known as the porcine stress syndrome (PSS), swine PSS, also known as malignant hyperthermia (MH), is characterized as sudden death and production of poor meat quality such as PSE (pale, soft and exudative) meat after slaughtering. PSS and PSE meat cause major economic losses in the pig industry. A point mutation in the gene coding for the ryanodine receptor (RYR1) in porcine skeletal muscle, also known calcium (Ca$^{2+}$) release channel, has been associated with swine PSS and halothane sensitivity. We used the PCR-RFLP(restriction fragment length polymorphism) and PCR-SSCP (single strand conformation polymorphism) methods to detect the PSS gene mutation (C1843T) in the RYR1 gene and to estimate genotype frequencies of PSS gene in Korean pig breed populations. In PCR-RFLP and SSCP analyses, three genotypes of homozygous normal (N/M), heterozygous carrier (N/n) and homozygous recessive mutant (n/n) were detected using agarose or polyacrylamide gel electrophoresis, respectively. The proportions of normal, carrier and PSS pigs were 57.1, 35.7 and 7.1％ for Landrace, 82.5, 15.8 and 1.7％ far L. Yorkshire, 95.2, 4.8 and 0.0％ for Duroc and 72.0, 22.7 and 5.3％ for Crossbreed. Consequently, DNA-based diagnosis for the identification of stress-susceptible pigs of PSS and pigs producing PSE meat is a powerful technique. Especially, PCR-SSCP method may be useful as a rapid, sensitive and inexpensive test for the large-scale screening of PSS genotypes and pigs with PSE meat in the pork industry.y.

• Journal of Korean Medicine Rehabilitation
• /
• v.15 no.1
• /
• pp.67-75
• /
• 2005

목 적 : 면역 세포에서 주로 생성되는 사이토카인인 인터루킨-1 (interleukin-1)은 다양한 신경내분비계와 대사 기능에 영향을 미치며, 비만인의 말초혈액 단핵구에서 증가하는 경향이 있는 것으로 연구보고 되고 있다. 본 연구의 목적은 $IL-1{\alpha}$ 다형성과 사상체질이 비만과 관련이 있는지를 조사하는데 있다. 연구방법 : 본 연구에서는 현저한 체질량지수 (body mass index, BMI) 다양성을 보이는 건강한 한국 여성 182명을 대상으로 $IL-1{\alpha}$ 유전자형을 분석하였다. 결 과 : T 대립 유전자는 BMI 감소와 관련이 있었다. BMI $27-30kg/m^2$ 그룹(group III)에서 T 대립유전자의 빈도는 $25kg/m^2$ 미만의 그룹(group I)에 비하여 유의하게 감소하였다 (odds ratio, OR, 0.141; 0.25% CI, 0.04-0.54). 더욱이 태음인 여성에서 $IL-1{\alpha}$ T 대립유전자의 빈도가 normal group에 비하여 overweight group (BMI $27-29kg/m^2$)에서 명확하게 감소하였다 (OR, 0.139; 95% CI, 0.04-0.54). 결 론 : 본 연구에서 175명의 체질분석결과 $BMI{\geq}25$인 군들의 태음인의 빈도가 높았으며, BMI는 CC genotype를 가진 사람에서보다 CT+TT genotype를 가진 사람에게서 더 낮았다. 태음인에서 동형접합 또는 이형접합 T 대립유전자가 $BMI{\geq}25$인 군에서 유의하게 감소하였다. 이상의 결과는 한국 여성에서 $IL-1{\alpha}$ 유전자 조절부위에 위치한 -889C/T 다형성과 비만 및 사상체질의 관련되는 것을 의미한다.

• Journal of Elementary Mathematics Education in Korea
• /
• v.20 no.4
• /
• pp.521-539
• /
• 2016

The structures of partitive and quotitive division of fractions are dealt with differently, and this led to using partitive division context for helping develop invert-multiply algorithm and quotitive division for common denominator algorithm. This approach is unlikely to provide children with an opportunity to develop an understanding of common structure involved in solving different types of division. In this study, I propose two approaches, measurement approach and isomorphism approach, to develop a unifying understanding of fraction division. From each of two approaches of solving quotitive division based on proportional reasoning, I discuss an idea of constructing a measure space, unit of which is a quantity of divisor, and another idea of constructing an isomorphic relationship between the measure spaces of dividend and divisor. These ideas support invert-multiply algorithm for quotitive as well as partitive division and bring proportional reasoning into the context of fraction division. I also discuss some curriculum issues regarding fraction division and proportion in order to promote the proposed unifying understanding of partitive and quotitive division of fractions.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.26 no.4
• /
• pp.403-411
• /
• 2020

This paper discusses the main findings of the development of the twin-hull Car ferry for island freight and passenger transport. The final model had a 19 m wide beam to create enough space for cars on the deck area and thus, enhance the economic feasibility in the market. The vessel had a V-shape with a bulbous bow to minimize the wave-making resistance and the hydrodynamic performance of the ship was verified through computational fluid dynamics. Multi-objective optimization problems of Pareto simulated annealing were used to achieve a weight reduction of approximately 3.9 % and reduce the manufacturing cost. The main results obtained in this study are expected to be useful to engineers and professionals in related industries interested in research on twin catamaran.

• Survey Research
• /
• v.10 no.3
• /
• pp.107-130
• /
• 2009

This study examines the factors affecting Korean firms' adoption of maternity protection practices. From a neo-institutional perspective, we argue that firms adopt institutionally legitimized practices mainly for their legitimacy concern rather than technical efficiency. Analysis of data from Establishment panel survey reveals that firms which belong to public sector, has received foreign investment, bench-mark leading firms, or have HR department are more actively adopting maternity protection practices and are showing lower level of decoupling between model and reality. These results imply that legitimacy concern matters among Korean firms in terms of adopting maternity protection practices. We propose that it is important for government agencies to take institutional factors into account when they try to promote maternity protection policy among firms in dealing with the problems of low fertility and gender equity.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.6
• /
• pp.431-437
• /
• 2017

In this study, based on the RPS algorithm, the application results to an electrically controlled suspension system using previewed road information are presented. Reducing the excessive vibration induced by a disturbance transmitted to the system and secure its stability is a major issue. In particular, in the automotive industry, the demand is constantly being raised. A typical external disturbance causing vibration and instability of a vehicle is an irregular roadway surface that contacts a running vehicle tire. Therefore, obtaining such profile information is an important process. The RPS algorithm using a multi sensor system was constructed and implemented in a real car. Through experimental work using the RPS system included non-contact type optical sensors, it could robustly reconstruct the road input profiles from the intermixed data onto the vehicle's dynamic motion while traveling at an uneven roadway surface. A controller with a preview control was designed in the framework of a semi-active suspension system based on the 7 degrees of freedom full vehicle model. The control performance of the system was evaluated through simulations and the results were compared with the passive vehicle condition. These results highlight the feasibility of the presented control frame.

• Journal of the Korean Orthopaedic Association
• /
• v.53 no.6
• /
• pp.459-465
• /
• 2018

Of the many factors that affect the clinical outcomes of orthopedic surgery, the surgical procedure is the most important. Robotics have been developed to perform the surgical procedures more accurately and consistently. Robotic surgical procedures in the orthopedic field were developed 20 years ago. Some designs of surgical robots have disappeared due to practical problems and complications, and an another design of surgical robots is emerging. To date, the use of robot surgery in arthroplasty is still controversial in terms of the clinical outcomes, practicality, and cost-effectiveness, even though it has been reported to be effective in the alignment and positioning of components in the field of artificial joints. Early robotic surgery was based mainly on active robot surgery according to the scheduled operation without the intervention of the operator. Recently the semi-active system of robotic surgery has been introduced. In a semi-active system, the robot constrains the surgeon to a haptic boundary defined by the computer based on the 3-dimensional imaging preoperative plan, and the operator can change the preoperative plan through real-time feedback during operation.

• Horticultural Science & Technology
• /
• v.31 no.3
• /
• pp.328-336
• /
• 2013

This study was conducted to evaluate imported tomato $F_1$ cultivars as breeding materials for the resistance to Tomato yellow leaf curl virus (TYLCV) by molecular markers and bioassay. From marker genotyping and disease evaluation of 40 $F_1$ cultivars, most of the cultivars declared as TYLCV-resistance carried heterozygous marker genotype for the TYLCV resistance genes Ty-1, Ty-3, or Ty-3a, and showed low disease rates. Whereas, 4 of 5 $F_1$ cultivars declared as intermediate resistance showed marker genotype for susceptibility and disease rates ranged 18.1-33.3%. However, the xx cultivars showed inconsistency in marker genotype and disease rate. Characterization of horticultural traits of the $F_1$ cultivars with TYLCV-resistance indicated that large-size fruit cultivars were higher in yield and similar in sugar contents and solid-acid ratio compared to a control cultivar preferred in the domestic market, although hardness remained to be a problem. On the other hand, cherry tomato cultivars showed lower yield and brix, but longer internode compared to a control cultivar, indicating that breeding for TYLCV-resistance using these cultivars will require more efforts and time compared to large-sized.

• Journal of Aquaculture
• /
• v.19 no.4
• /
• pp.281-287
• /
• 2006

Intraspecific diploid androgenesis was achieved in mud loach (Misgurnus mizolepis) by the inhibition of the first mitotic division using combined thermal treatment. A combined thermal treatment (heat shock at $40.5\;^{\circ}C$ for 120 sec followed by cold treatment at $1\;^{\circ}C$ for 45 min) applied to the 1st metaphase of cell division (28 min post insemination at $25\;^{\circ}C$) successfully recovered viable androgenetic diploidy. Mean hatching success of the androgenetic diploid group was 29.6%, and the average yield out of total eggs taken was about 7% assessed at 1 week of age. However, relatively large variations in the yield of diploid androgenesis were observed among different egg batches used as cytoplasmic donors. Successful diploidization was confirmed by flow cytometric analysis, and parthenogenic reproduction in a paternal exclusive manner was verified with transgene dosage. Significant mortality was found in most androgenetic groups especially from hatch to 1 month of age, although such mortality was stabilized later.