• Journal of Mechanical Science and Technology
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• v.20 no.10
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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.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.06a
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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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• v.16 no.2
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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.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.11a
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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.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.4
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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.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.10 s.253
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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.

• Journal of Korean Port Research
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• v.8 no.2
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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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• v.20 no.2
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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.

• Journal of Navigation and Port Research
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• v.38 no.4
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• pp.409-419
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• 2014

In accordance with the global age, countries in the world try to dedicate to collaboration among them through ODA (Official Development Assistance), in order to solve the-rich-get-richer and the poor-get-poorer problems among countries, to develop the developing countries' economies, and to improve their level of social welfare. Also, Korea is so active in ODA as a member of OECD, even if it is in the initial process. Nowadays, in Korea, the importance of ODA in the field of port has been brought into relief. Accordingly, the paper intends to analyze the dilemma structure of port ODA from the perspectives both of new institutionalism and Samaritan's dilemma game, and it tries to seek the improvements of ODA institutions to create effective outcomes based on the analysis. Through the analysis, dilemma structure was identified regarding the institutions of port ODA. And the results of the analysis suggested the improvements of port ODA institutions including strengthening of on-the-spot aid system, establishment of payoffs system for inducing recipient countries' efforts, and institutionalization of reliable threat. It would contribute to develop the theoretical model of ODA analysis and create effective outcomes of ODA in the field of ports.

• The Korean Journal of Pain
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• v.27 no.2
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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.