• Journal of Mechanical Science and Technology
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• 제20권10호
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• pp.1626-1637
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• 2006

The pressure pulsation due to the gear geometry of the gerotor (generalized rotor) pump mainly occurs in an instant that the chamber of the gerotor enters the delivery port and leaves the suction one. Such a pressure pulsation may result in undesirable vibration and noise of pump components as well as cavitation in hydraulic system. Therefore, it is very important to examine the pressure characteristic of the gerotor pump at its design and analysis stages. In this paper, in order to reduce the pressure pulsation in the gerotor pump, the port plate with the relief grooves is designed by referring to as notch of vane pump and relief groove of piston pump. A series of the theoretical analyses on the pressure pulsation is performed in consideration of various design parameters of the port plate, including the installation positions of the port inlet/outlet and the groove width, and the operating conditions such as rotational velocity and delivery pressure.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1999년도 제29회 춘계학술대회
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• pp.133-140
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• 1999

It is possible for a volume of fluid to become trapped in the space between two adjoining teeth ad the tips of the teeth engage in Gear Pump with involute teeth. This trapped fluid leads to several harmful results, for example fluctuating pressure and aeration of pump. In this study, hence, theoretical and experimental analyses on this 'Trapping' were accomplished as using relief port(or escape port), one of the means for avoid it. Also, the grasp and analysis on variational type of the internal pressure in parallel with above experiments are achieved so that hydrodynamic behaviors in pump were contemplated.

• Tribology and Lubricants
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• 제16권2호
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• pp.126-132
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• 2000

It is possible for a volume of fluid to become trapped in the space between two adjoining teeth as the tips of the teeth engage in Gear Pump with involute teeth. This trapped fluid leads to several harmful results, for example fluctuating pressure and aeration of pump. In this study, hence, theoretical and experimental analyses on this'Trapping'were accomplished as using relief port(or escape port), one of the means for avoid it. Also, the grasp and analysis on variational type of the internal pressure in parallel with above experiments are achieved so that hydrodynamic behaviors in pump were contemplated.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1999년도 제30회 추계학술대회
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• pp.114-120
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• 1999

It is possible for a volume of fluid to become trapped in the space between two adjoining teeth and the tips of the teeth engage in Gear Pumu with involute teeth. This trapped fluid leads to several harmful results, for example fluctuating pressure and aeration of pump. In this study, hence, theoretical and experimental analyses on this 'Trapping' were accomplished as using relief port, one of the means for avoiding it. Also, the grasp and analysis on variational type of the internal pressure in parallel with above experiments are achieved so that hydrodynamic behaviors in pump were contemplated.

• 대한기계학회논문집B
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• 제28권4호
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• pp.406-414
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• 2004

In Gerotor pump, the pressure pulsations which occur due to the pump geometry result in vibration and noise of pump elements as well as cavitation in hydraulic system when the chambers of gerotor enter the delivery port and leave the suction port. Therefore it is important to study on the pressure pulsations before design and analysis of characteristics in Gerotor pump. In this paper, to reduce the unnecessary pressure pulsations, the port plate of Gerotor pump is designed based on the notch of the vane pumps and the relief grove of the piston pumps. The theoretical analysis of the pressure pulsations is performed in consideration of design parameters of the port plate which include each port positions and groove width and operating conditions which include rotational velocity and delivery pressure.

• 대한기계학회논문집B
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• 제30권10호
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• pp.1019-1025
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• 2006

Numerical simulations were conducted on the gerotor type oil pump. Three oil pump models having different port and groove shape were considered. Firstly, two original models (baseline & variant.1 model) were simulated in order to validate the accuracy of the simulation results and to better understand the flow characteristics in the pump. It was found that the cavitation phenomenon as well as the teeth tip leakage is most important parameter on the pump performance. Based on the simulation results of the original models, final model (variant.2 model) which has improved port shape and pressure relief valve is suggested to enhance pump performance and to reduce driving torque. The volumetric efficiency and the hydraulic torque of the Variant.2 model is improved 4% and reduced 6.1% each at 2000RPM in experiment.

• 한국항만학회지
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• 제8권2호
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• pp.1-35
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• 1994

The main arterial which runs through the in City of Pusan, carries about 60% of downtown traffic or more, maintains about 20% yearly increase in traffic is severely suffering from the traffic congestion because of concentrated traffic volumes regardless of peak-time periods. The purpose of this study was to grasp the traffic, geometric, and signal conditions of the main arterial through the Videologging System Techniques, perform the transportation system analyses, and finally suggest the improvements which could increase the travel capacity, reduce the average delay and fuel consumption with the optimal conditions of signal system. The following conclusions were drawn : firstly the traffic system should be shifted for the travel distribution on the arterial during the peak time periods, secondly the roadway system of the arterial reviewed for left-turn traffic during the peak time periods, and thirdly the signal system of intersection reconstructed for signal optimization or progression within the range of cycle length suggested.

• The Korean Journal of Pain
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• 제20권2호
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• pp.240-245
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• 2007

It is important to treat cancer-related pain in cancer patients to ensure the life quality of the patient, as well as to improve their life span. It has been estimated that at least 5% of cancer patients have pain refractory to medical treatment. Therefore, the need for epidural or intrathecal analgesia with opioids and local anesthetics is indicated if systemic treatment has failed. Intrathecal catheter placement and implantation of the injection port for administration of opioids and local anesthetics may improve pain relief in patients who are unresponsive to epidural routes. Although intrathecal implantation has several complications, similar infection rates have been reported between intrathecal and epidural administration. In addition, intrathecal administration showed better outcomes, including improved pain control, lowered daily doses, and an improvement in the level of drowsiness experienced when compared to epidural administration. We report here a case in which a terminal cancer patient was treated using an intrathecal catheter and subcutaneous port. The patient had cancer-related pain that could not be controlled by epidural opioid administration. Based on the results presented here, we suggest that intrathecal implantation is a feasible long term pain management method for intractable cancer pain patients.

• 한국항해항만학회지
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• 제38권4호
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• pp.409-419
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• 2014

국제화 시대에 발맞추어 세계 각국은 국가 간 빈익빈 부익부 현상을 해결하고 개발도상국의 경제발전 및 복지수준 향상을 위해, 공적개발원조(ODA; Official Development Assistance)를 통한 그들 간의 협력에 힘쓰고 있다. 과거 수원국에서 공여국의 입장으로 위상이 변화된 우리나라 역시 아직 초기단계에 머물러 있지만, OECD의 회원국으로서 ODA 사업에 적극 동참하고 있다. 특히 최근 들어 우리나라에서는 항만과 관련된 분야에서 ODA의 중요성이 부각되고 있다. 따라서 본 연구는 신제도주의와 사마리아인의 딜레마 게임의 관점에서, 우리나라 항만분야 ODA의 현황 및 관련 제도를 분석하여 사마리아인의 딜레마 상황을 발생시킬 수 있는 구조를 찾아내고, 이러한 딜레마를 해소하기 위한 제도적 방안을 모색하는 것을 연구목적으로 하였다. 분석을 통해서 항만분야 ODA 제도와 관련된 딜레마 구조를 확인하였다. 그리고 분석결과는 현장 중심 원조체제의 강화, 수원국의 협력을 유도하는 보상체제 확립, 신뢰할 수 있는 협박의 제도화 등과 같은 제도개선방안들을 제안하였다. 이와 같은 연구의 분석결과는 ODA 연구의 이론적 모형을 개발하고 항만분야 ODA의 효과성을 제고시키는데 기여할 수 있을 것이다.

• The Korean Journal of Pain
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• 제27권2호
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• pp.139-144
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• 2014

Background: To manage intractable cancer pain, an alternative to systemic analgesics is neuraxial analgesia. In long-term treatment, intrathecal administration could provide a more satisfactory pain relief with lower doses of analgesics and fewer side-effects than that of epidural administration. However, implantable drug delivery systems using intrathecal pumps in Korea are very expensive. Considering cost-effectiveness, we performed epidural analgesia as an alternative to intrathecal analgesia. Methods: We retrospectively investigated the efficacy, side effects, and complications of epidural morphine and local anesthetic administration through epidural catheters connected to a subcutaneous injection port in 29 Korean terminal cancer patients. Patient demographic data, the duration of epidural administration, preoperative numerical pain rating scales (NRS), side effects and complications related to the epidural catheterization and the drugs, and the numerical pain rating scales on the 1st, 3rd, 7th and 30th postoperative days were determined from the medical records. Results: The average score for the numerical pain rating scales for the 29 patients decreased from $7{\pm}1.0$ at baseline to $3.6{\pm}1.4$ on postoperative day 1 (P < 0.001). A similar decrease in pain intensity was maintained for 30 days (P < 0.001). Nausea and vomiting were the most frequently reported side effects of the epidural analgesia and two patients (6.9%) experienced paresthesia. Conclusions: Epidural morphine and local anesthetic infusion with a subcutaneous pump seems to have an acceptable risk-benefit ratio and allows a high degree of autonomy to patients with cancer pain.