• Journal of Yeungnam Medical Science
• /
• v.37 no.1
• /
• pp.22-31
• /
• 2020

There has been a growing concern and subsequent interest surrounding numerous reproductive toxic agents found in various working and non-working environments. Meanwhile, there have been many efforts in medical fields such as toxicology and epidemiology applying experimental studies to elucidate reproductive toxic agents' characterization and health effects. However, there remains insufficient research data and inadequate evidence in humans. Adverse reproductive outcomes vary from transient, moderate health effects to severely detrimental consequences, such as permanent infertility or childhood cancer of one's offspring. Furthermore, upon exposure to toxic agents, the latent period before reproductive health effects are observed is relatively short compared to other occupational diseases (e.g., occupational cancer); instant action is required once exposure to reproductive toxic agents is detected. Therefore, it is very important for workers and healthcare professionals to know about the reproductive toxic agents they are likely to be exposed to. In this review, we discuss the general epidemiology of reproductive health in Korea, and the information regarding these reproductive toxic agents.

• Journal of Korean Neurosurgical Society
• /
• v.40 no.1
• /
• pp.28-30
• /
• 2006

Two patients presented with amaurosis fugax[AMF]. despite treatment with antiplatelet drugs and anticoagulants due to previous transient ischemic attacks. Angiography demonstrated severe stenosis in the cavernous and petrous internal carotid artery[ICA] respectively, with reduced flow in the ophthalmic artery[OA]. Endovascular stent placement in both patients resulted in normalization of the vessel lumen of the stenotic vessel segments. In addition, complete restoration of OA flow was noted immediately after stenting. Both patients showed no further episode of AMF over a follow-up period of 38 and 23 months respectively. Our clinical and angiographic findings suggest that hemodynamic Insufficiency in retinal vasculature caused by a stenosis of the cavernous or petrous ICA can be treated successfully by endovascular stent.

• Journal of Korean Neurosurgical Society
• /
• v.41 no.5
• /
• pp.327-329
• /
• 2007

A 44-year-old woman presented with recurrent, transient episodes of left-side hemiparesis. She had received a radiation dose of 6120 cGy to her cervical region for parotid gland carcinoma 13 years previously. Cerebral angiography revealed a long, irregular tight stenosis involving the right extracranial internal carotid artery [ICA] and common carotid artery [CCA], measuring approximately 90% at the most severe narrowing according to North American Symptomatic Carotid Endarterectomy Trial criteria. Endovascular stent placement resulted in restoration of the carotid lumen to about 80% of its original diameter. She showed no further ischemic events during the follow-up period of 48 months. Our clinical and angiographic findings suggest that carotid stenting is considered a safe and effective treatment option in patients with radiation-induced carotid stenosis.

• Proceedings of the KIPE Conference
• /
• 2004.07a
• /
• pp.87-91
• /
• 2004

In this paper, the paralleled forward converter, that is generally used as the power supply for the low voltage, high current load, is described. The proposed forward converter for battery charging could be provided the power without failure not only in steady state but also in the transient period by the step load variation or the unexpected faults among the converter modules. Each converter nodule designed is operated alone with the self closed controller for the elevation of stability, performance, reliability, and maintainability. The frequency response of the designed converter module is analyzed, and the stability is confirmed in analytic method. And the experiments of the paralleled battery charger are carried out in steady state, in the step load variation.

• Proceedings of the KIPE Conference
• /
• 2004.07a
• /
• pp.1-5
• /
• 2004

This paper describe a control scheme for direct torque control of BLDC Motor. The proposed Luenberger Observer scheme calculate flux errors in order to control the torque and flux more correctly. This proposed control scheme has not the requirement of a separate current regulator and proportional-integral (PI) control of the flux and torque, there by improving transient performance and also has the advantage of less torque ripple in steady state with a fixed switching period. The effect of proposed method has been proven by simulations.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.50 no.12
• /
• pp.561-565
• /
• 2001

Recent trend of increasing automated factories needs supply of high quality power from the utilities. Among the items of the power quality, voltage sag can be compensated by Dynamic Voltage Restorer(DVR). The key feature of the DVR is high response with less transient period to recover from the voltage sag due to the lightning or line-to-ground faults. In this paper we report that $H_{\infty}$ controller is very promising for the practical application to the controller of DVR. Experimental results shown in this paper was obtained by applying the control algorithm to 20 kVA DVR system. The experimental set consists of IGBT-based three phase inverter and the TMS320C32-60 DSP used for main processor of the control board. To simulate the 50% voltage sag, the SCR-based experimental set was constructed.

• Proceedings of the KIEE Conference
• /
• 2006.07a
• /
• pp.85-86
• /
• 2006

This Paper Presents a study for the Korea power system at yearly peak load time in 2006 summer period. The power system become more complex due to the gradual increment of power demand. We analyze the problems in power system operation, by the use of PSS/E(power flow, fault and transient stability study) and VSAT for voltage stability The results of establishment of power system operating plan and countermeasure are described.

• International Journal of Air-Conditioning and Refrigeration
• /
• v.7
• /
• pp.22-32
• /
• 1999

A multi-type heat pump controls the mass flow rate of the working fluid to cope with variable heat loads when it is under dynamic load condition. This paper describes the exergy analysis associated with the unsteady response of a heat pump. First, a basic heat pump cycle is examined at a steady state to show the general trends of exergy variations in each process of the cycle. Entropy generation issue for the heat exchangers is discussed to optimize the heat pump cycle. Secondly, the performance of the inverter-driven heat pump is compared to that of the conventional one when the heat load is variable. Thirdly, the exergy destruction rate of the heat pump with On/Off operation is calculated by simulating the thermodynamic states of the working fluid in the condenser and the evaporator. The inefficiency of On/Off operation during the transient period is quantitatively described by the exergy analysis.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.10 no.2
• /
• pp.155-164
• /
• 1998

A multi-type heat pump controls the mass flow rate of the working fluid to cope with variable heat loads when it is under dynamic load condition. This paper describes the exergy analysis associated with the dynamic response of heat pump. First, a basic heat pump cycle is examined at steady state to show the general trends of exergy changes in each process of the cycle. Entropy generation issue in the exchangers is discussed to optimize the heat pump cycle. Second, the performance of the inverter-driven heat pump is compared to that of the conventional one when the heat load is variable. Third, the exergy destruction rate associated with the ON/OFF operations of the heat pump is calculated by simulating the thermodynamic states of the condenser and the evaporator. The inefficiency of the ON/OFF operation during the transient period is quantitatively revealed by the exergy analysis.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2008.05a
• /
• pp.67-74
• /
• 2008

The regional-scale transient groundwater-river interaction model is developed to gain a better understanding of the regional-scale relationships and interactions between groundwater and river system and quantify the residual river flow after groundwater abstraction from the aquifers with climate variability in the Waimea Plains, New Zealand. The effect of groundwater abstraction and climate variability on river flows is evaluated by calculating river flows at the downstream area for three different drought years (a 1 in 10 drought year, 1 in 20 drought year, and 1 in 24 drought year) and an average year with metered water abstraction data. The effect of future water demand (50 year projection) on river flows is also evaluated. A significant increase in the occurrence of zero flow, or very low flow of 100 L/sec at the downstream area is predicted due to large groundwater abstraction increase with climate variability. Modeling results shows the necessity of establishing dynamic cutback scenarios of water usage to users over the period of drought conditions considering different climate variability from current allocation limit to reduce the occurrence of low flow conditions at the downstream area.