• Journal of the Korean Institute of Intelligent Systems
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• v.3 no.2
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• pp.18-35
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• 1993

The water level control system of the steam generator in a pressurized water reactor and its control problems are analysed. In this work the stable control strategy during the low power operation and transient states is studied. To solve the problem, a fuzzy logic control method is applied as a basic algorithm of the controller. The control algorithm is based on the operator's knowledges and the experiences of manual operation for water level control at the compact nuclear simulator set up in Korea Atomic Energy Research Institute. From a viewpoint of the system realization, the control variables and rules are established considering simpler tuning and the input-output relation. The control strategy includes the dynamic tuning method and employs a substitutional information using the bypass valve opening instead of incorrectly measured signal at the low flow rate as the fuzzy variable of the flow rate during the pressure control mode of the steam generator. It also involves the switching algorithm between the control valves to suppress the perturbation of water level. The simulation results show that both of the fine control action at the small level error and the quick response at the large level error can be obtained and that the performance of the controller is improved.

• Journal of the Institute of Convergence Signal Processing
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• v.14 no.4
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• pp.222-230
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• 2013

Retinal bipolar cells according to the light stimulus respond to potential slowly, emit neurotransmitter release(glutamine acid) to depend on membrane potential. In this paper, the several physiological information on neurotransmitter release mechanism in the presynaptic terminal of the ON-type bipolar cells are incorporated into the formula model. The source of fast components and slow components of neurotransmitter release was arranged in parallel, this model was able to reproduce the membrane potential and intracellular $Ca^{2+}$ concentration dependence of neurotransmitter release faithfully. In addition, because the fast releasable components of neurotransmitter was represented by the membrane potential dependence of trapezoid type, whereas the slow releasable components was represented by the membrane potential dependence of a bell type, $Ca^{2+}$ concentration rise in intracellular is suppressed by $Ca^{2+}$ buffer to reduce slow releasable components, it was confirmed that the membrane potential dependence of neurotransmitter release was characteristics of a trapezoid type. And, in the light response of ON type bipolar cell, the result of the simulation of the neurotransmitter release caused by the components of transient and persistent was that the start of light response occurred the fast release of neurotransmitter, it was confirmed that the transient component and persistent component of the light response occurred the slow release. It was confirmed that the later of persistent component of the light response occurred due to the continuous release by synaptic vesicle supplemented from the storage pool.

• The KIPS Transactions:PartA
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• v.8A no.4
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• pp.319-330
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• 2001

In virtual memory system, when a process attempts to access a page that is not resident in memory, the system generates and handles a page fault that causes unpredictable delay. So virtual memory system is not appropriate for the real-time system, because it can increase the deadline miss ratio of real-time task. In multimedia system, virtual memory system may degrade the QoS(quality of service) of multimedia application. Furthermore, in general-purpose operating system, whenever a new task is dynamically loaded, virtual memory system suffers from extensive page fault that cause transient overloading state. In this paper, we present efficient overloading control mechanism called RBPFH (Rate-Based Page Fault Handling). A significant feature of the RBPFH algorithm is page fault dispersion that keeps page fault ratio from exceeding available bound by monitoring current system resources. Furthermore, whenever the amount of available system resource is changed, the RBPFH algorithm dynamically adjusts the page fault handling rate. The RBPFH algorithm is implemented in the Linux operating system and its performance measured. The results demonstrate RBPFH\`s superior performance in supporting multimedia applications. Experiment result shows that RBPFH could achieve 10%∼20% reduction in deadline miss ratio and 50%∼60% reduction in average delay.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.5
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• pp.97-106
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• 2009

An objective of this study is to give practical information that could be used for calculating pollutant emission factors and fuel economy from Korean Inspection & Maintenance program, which has been using steady state acceleration simulation mode. Concentration results from I/M test is adequately converted to mass emission factors and fuel efficiency data, which have unit of g/km and km/L, respectively. Exhaust volume flow(EVF), which is for converting emission result from concentration to mass, is measured by tracer method in various vehicle speed - power condition. It is found that there is an apparent second order relationship between EVF and vehicle inertia weight. EVF is expressed in function of vehicle inertia weight in order to estimate EVF in I/M site without measuring device. Converted mass emission results from measured EVF and raw emission analyzer show a satisfactory agreement with those from conventional CVS-bag type measurement system. Mass emission factors and fuel efficiency from measured EVF and estimated EVF also show good agreement to each other. Considering that an I/M program has great advantages to recruit-based emission test in terms of the number of test vehicle, the information in this study can be used for developing an alternative procedure to collect more various data to establish national database of mobile emission factors and fuel economy, even though the driving cycle in I/M program is steady state cycle rather than transient cycle.

• Journal of Korean Neurosurgical Society
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• v.29 no.8
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• pp.1063-1068
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• 2000

Objectives : To determine the contribution of cranial magnetic resonance angiography(MRA) for the evaluation of patients with ischemic cerebrovascular accident. Methods : Magnetic resonance image(MRI) and MRA studies performed on 34 patients with ischemic stroke were retrospectively reviewed with the clinical records. Results : There were 9 transient ischemic attacks and 25 completed strokes in our series. Twenty-three of 34 MRA examinations(68%) were positive for stenosis or occlusion. The distribution of stenotic or occlusive vascular lesions were correlated with the location of infarction in 22 of the 23 positive cases(96%). MRA provided additional information not obtained from the MRI in 19 cases(56%). Conclusions : Vascular lesions demonstrated on intracranial MRA show a high correlation with infarct distribution. MRA provided information adjunctive to conventional MRI in a majority of cases. We conclude that MRA is an important noninvasive component of the complete evaluation of ischemic stroke.

• The Journal of Information Technology
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• v.7 no.2
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• pp.69-76
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• 2004

This paper presents the results of spectral analysis about waveforms and leakage current waveforms on contaminated silicon insulators under various environment conditions.(salt fog, clean fog, rain). The larger the leakage current during 200ms, the higher the power spectrum at 60Hz. If contaminated insulators suffers from high salt density fog, the leakage current occurs with high crest value intermittently, results in the low spectrum. Analysis of leakage current data showed that this electrical activity was characterized by transient arcing behavior contaminants are deposited on the insulator surface during salt fog tests. This provides a path for the leakage current to flow along the surface of the insulator. It is important to have an indication of the pollution accumulation in order to evaluate the test performance of a particular insulator. If the drop in surface resistivity is severe enough, then the leakage current may escalate into service interrupting flashover that degrade power quality.

• Reproductive and Developmental Biology
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• v.33 no.2
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• pp.77-83
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• 2009

Erythropoietin (EPO), a glycoprotein hormone produced from primarily cells of the peritubular capillary endothelium of the kidney, is responsible for the regulation of red blood cell production. We have been investigating the roles of glycosylation site added in the biosynthesis and function of recombinant protein. We constructed three EPO mutants ($\Delta$69, $\Delta$105 and $\Delta$69,105), containing an additional oligosaccharide chains. EPOWT and EPO$\Delta$69 were effectively expressed in transient and stably transfected CHO-K1 cell lines. But, it wasn't detected any protein in the culture medium of EPO$\Delta$105 and EPO$\Delta$69,105 mutants. The growth and differentiation of EPO-dependent human leukemic cell line (F36E) were used to measure the cytokine dependency and in vitro bioactivity of rec-hEPO. MTT assay values were increased by survival of F36E cells at 24h. To analysis biological activity in vivo, two groups of ICR-mice (7 weeks old) were injected subcutaneously with 10 IU per mice of rec-hEPO molecules on days 0 and 2. Red blood cell and hematocrit values were measured on 6 days after the first injection. The hematocrit values were remarkably increased in all treatment groups. The pharmacokinetic analysis was also affected in the mice injected with rec-hEPO molecules 2.5 IU by tail intravenous. Protein samples were detected by Western blotting. An EPO$\Delta$69 protein migrated as a broad band with an average apparent molecular and detected slightly high band. Enzymatic N-deglycosylation resulted in narrow band and was the same molecular size. The biological activity of EPO$\Delta$69 was enhanced to compare with wt-hEPO. The half-life was longer than wt-hEPO. The results suggest that hyperglycosyalted recombinant human erythropoietin (EPO$\Delta$69) may have important biological and therapeutic good points.

• International Commerce and Information Review
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• v.15 no.2
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• pp.345-364
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• 2013

This paper analyzed the Trade Structure of environmental industry in Korea and some major countries in preparation for The Doha Development Agenda (DDA) Trade Liberalization Negotiation in the environmental goods. Based on 161 environmental goods list proposed by OECD, this paper examined the Trade Returns of worldwide environmental goods during the past 10 years from 2002 to 2011. The analysis showed that Korean environmental goods' International Market Share(IMS) in the world was 3.2%; trade specialization index(TSI) -0.128; Revealed Comparative Advantage(RCA) 1.002 in 2011. And Korea Export Similarity Index(ESI) to Japan was the highest rank in the world market. According to the results of investigation, it is clear that International Competitiveness of the Korean Environmental Industry was received a relatively poor evaluation compared with Korean trade scale. To strengthen the competitiveness, it is required that Korean government should make an effort to boost domestic environmental industry and promote systematically Trade Liberalization Negotiation including the enforcement of transient period for Korean environmental goods in the next DDA Negotiation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.3B
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• pp.375-390
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• 2004

Domain Name System(DNS), one of the most important Internet services, handles mapping from host names to Internet addresses and vice versa, and precedes many Internet applications such as Web, e-mail, file transfer, etc. In this paper, we propose a structural design of a generic name server system providing name services for a huge domain for the purpose of improving the performance as well as the reliability of the system. We demonstrate the validity of the design by implementing and running a testbed system. Our testbed employs a couple of master name sowers for distributing the service overhead over two, rather than one, servers and for achieving high availability of the system as a whole. We suggest the use of dynamic update to add and delete records from a zone for which the name server has authority. The slave name servers located remotely then get a new, updated copy of the zone via incremental zone transfers(IXFRs). The experiments with the implemented testbed show that the proposed structure would easily manage increasing demands on the server power, and be highly available in the face of transient faults of a module in the system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.10
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• pp.2329-2334
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• 2012

In this paper, we performed a study of damage assessment model development to analyze the initial nuclear pulse radiation damage to semiconductor devices for military weapon systems. At first we modeled(M) the nuclear pulse radiation and diode device, and simulated(S) the output characteristics of the device to the input. Then the manufactured diodes which had the same characteristics with the modeled one were irradiated to the similar pulsed type radiation and their output signals were measured simultaneously. Error between the M & S results and the measured values of the analysis was 22.9%. Through the error value we could confirm that the damage assessment model simulated the TREE effects with a quite accuracy.