• Journal of Power Electronics
• /
• 제14권1호
• /
• pp.22-29
• /
• 2014

Current sharing between modules in a converter parallel operation is very important for the reliability of the system. This paper proposes an improved droop method that can effectively improve current sharing accuracy. The proposed method adaptively adjusts the output voltage set-point of each module according to the current set-points. Unlike conventional droop control, modules share a signal line to communicate with each other. Nevertheless, since signals are simple and in digital form, the complexity of the circuitry is much less and noise immunity is much better than those of conventional methods utilizing communication. The operation principle and design procedure of the proposed method are described in detail. Results of the experiment on two boost converters operating in parallel under the specification of a TFT LCD TV panel power supply verify the validity of the proposed scheme.

• 한국경영과학회:학술대회논문집
• /
• 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
• /
• pp.106-111
• /
• 2005

In nuclear power plant, the source of the energy is generated from the nuclear fuel rod. Given a certain level of consumption, the burnt fuel rod should be removed and replaced by a new(fresh) one. The burnt fuel is approximately one third of the whole fuel rods. Currently, this operation is done manually using paper documents and verbal communication and consumes a lot of operation time. In this study, we develop an computerized operation process of nuclear fuel rod replacement procedure based on the ERP(Enterprise Resource planning) methodology.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.43-45
• /
• 2004

This paper represents the improvement of floating point operation for AC servo motor controller based on fixed point operation DSP. TMS320F2812 has fixed point operation processing structure. The controller parameters are modified to the digitized data by scaling the original parameters. TMS320F 2812 is a 32-bit processor, and it could have enough accuracy to get the digitized data this procedure is implemented and the experiments controling a AC servo system.

• Journal of Chest Surgery
• /
• 제23권5호
• /
• pp.1027-1034
• /
• 1990

Pectus excavatum, commonest developmental anomaly of chest wall, is manifested by depression of the sternum and lower costal cartilages that is of surgical interest. From 1982 through 1990, fifteen patients have undergone surgery for treatment of pectus excavatum and treated by Ravitch operation: 5, Modified Ravitch operation; 4, Wada operation, 1 and Modified Wada operation, 5. There was familial history of pectus excavatum in 3 patients. Associated congenital anomaly were seen in 6 patients; scoliosis in 3 patients, right inguinal hernia in 1, polydactyly in 1 and patent ductus arteriosus in 1 patent. Postoperative minor complications were developed in 3 cases; pneumothorax, 2 cases; pleural effusion, 2 cases; wound infection and dehiscence, 1 cases; pressure sore due to strut malposition, 2 cases; flail chest and 2 cases; seroma. The incidence of the postoperative complications were more common in cases who were treated by metal strut, pin or other prosthetic materials for supporting the chest wall integrity than the standard corrective procedure. All cases have no recurrence of chest wall depression and operative death.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2006년도 춘계학술대회 논문집
• /
• pp.381-385
• /
• 2006

This research introduces easy tool manufacturing method regarding tool manufacturing procedure. In the conventional method, wire cutting machining and lapping operation of corner and render region were performed after shrink-fitting to ensure the accuracy of gear profile. But lapping operation is very difficult due to corner and render is located deep inside of die. In this research, wire cutting operation was performed after $1^{st}$ ring was shrink-fitted to ease lapping operation and increase the accuracy of corner radius. Before $2^{nd}$ ring fitting, lapping was completed. Elastic deformation amount due to $2^{nd}$ ring fitting and cold forging was calculated through finite element analysis and wire cutting specification was offset in that amount. Comparison of gear dimension between analysis and forged part ensures the validity of new manufacturing methods.

• 한국품질경영학회:학술대회논문집
• /
• 한국품질경영학회 2004년도 품질경영모델을 통한 가치 창출
• /
• pp.513-516
• /
• 2004

Evolutionary operation is useful to improve on-line full-scale manufacturing processes by systematically changing the levels of the process variables while meeting production schedule. Evolutionary operation was developed using two or three process variables for process operators who are not good at statistics. Recently, when a product is developed, it is very important for the engineers to make the production line stable as soon as possible. And there are many causes which have influences to the product performance. This paper presents an evolutionary operation procedure with many process variables using saturated two level fractional factorial designs including Plackett-Burman design.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2009년도 춘계학술대회 논문집
• /
• pp.198-205
• /
• 2009

일반적으로 철도차량은 획득비용보다 운영 유지보수비용이 높다는 것이 알려져 있다. 운영 유지보수비용의 절감을 위해서는 운영 유지보수 비용 측면에서 효율적으로 설계된 철도차량을 획득하는 것이 매우 중요하다. 따라서 철도차량의 획득단계에서부터 운영 유지보수비용을 포함한 수명주기비용을 고려하는 것이 필요하다. 본 연구는 철도차량의 획득단계에서 수명주기비용을 고려하기 위한 절차 및 수명주기비용 모형을 제시한다.

• Journal of Chest Surgery
• /
• 제28권1호
• /
• pp.65-68
• /
• 1995

Pectus excavatum occasionally occurs in patients who have underlying cardiac disease, especially Marfan syndrome. This report describes a patient with pectus excavatum who had ascending aortic aneurysm with aortic regurgitation and anterior leaflet prolapse of mitral valve. This patient underwent replacement of aortic valve and ascending aorta with 25 mm SJM valved conduit graft[Bentall operation with Cabrol shunt , and mitral valve replacement with SJM 31 mm, the pectus excavatum was corrected at the time of completion of the intracardiac operation with the modified sternal turnover. This procedure offered excellent operative exposure for the inracardiac operation with prevention of low cardiac output after operation due to depressed sternum and maintained chest wall stability resulting good cosmetic chest wall appearance. This patient recovered and discharged in good postoperative result with minimal temporary peroneal nerve palsy in his left leg.

• 대한치과의사협회지
• /
• 제13권7호
• /
• pp.629-632
• /
• 1975

The clinical investigation and operation procedure were described on the gunshot wound which involved on soft, hard palate and nasal cavity. The patient, 19 years old, female, admitted in Han Yang Medical Center with clinical diagnosis of maxillofacial injuries on Nov. 1973. No Significant signs include of airway obstruction, Oro-nasal bleeding were revealed only exception of rupture and perforation on the soft, hard palate. For closure and reduction of destructed palatal wound, operation was done in out patient dental clinic under local anesthesia by means of Langenbeck method. And to control of post-operative inflammation and reactive swelling, administration of accurate antibiotics and physical therapy were performed for 5 days after operation. On the 10th day after administration, patient was discharged with satisfactory result of operation.

• 대한산업공학회지
• /
• 제29권4호
• /
• pp.334-344
• /
• 2003

A mixture experiment is a special type of response surface experiment in which factors are the ingredients or components of a mixture, and the response is a function of the proportions of each ingredient. Evolutionary operation is useful to improve on-line full-scale manufacturing process by systematically changing the levels of the process variables without jeopardizing the product. This paper presents an evolutionary operation procedure with mixture variables for large-scale mixture production process which can be beneficial to practitioners who should improve on-line mixture quality while maintaining the production amount of the mixture product.