• The KIPS Transactions:PartC
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• v.11C no.1
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• pp.47-54
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• 2004

The growth of computer resource and network speed has increased requests for the use of remotely located computer systems by connecting through computer networks. This phenomenon has hoisted research activities for application service provision that uses server-based remote computing paradigm. The server-based remote computing paradigm has been developed as the ASP (Application Service Provision) model, which provides remote users through application sharing protocol to application programs. Security requirement such as confidentiality, availability, integrity should be satisfied to provide ASP service using centralized computing system. Existing Telnet or FTP service for a remote computing systems have satisfied security requirement by a simple access control to files and/or data. But windows-based centralized computing system is vulnerable to confidentiality, availability, integrity where many users use the same application program installed in the same computer. In other words, the computing system needs detailed security level for each user different from others, such that only authorized user or group of users can run some specific functional commands for the program. In this paper, we propose windows based centralized computing system that sets security policies for each user for the use of instructions of the application programs, and performs access control to the instructions based on the security policies. The system monitors all user messages which are executed through graphical user interface by the users connecting to the system. Ail Instructions, i.e. messages, for the application program are now passed to authorization process that decides if an Instruction is delivered to the application program based on the pre-defined security polices. This system can be used as security clearance for each user for the shared computing resource as well as shared application programs.

• Korean Journal of Clinical Pharmacy
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• v.8 no.1
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• pp.13-18
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• 1998

The purpose of this study was to determine pharmacokinetic parameters of vancomycin using the compartment model dependent and compartment model independent analysis in 6 Korean normal volunteers and 8 ovarian cancer patients. Vancomycin was administered 1.0 g bolus by IV infusion over 60 minutes. The elimination rate constant ($\beta$), volume of distribution (Vd), total body clearance (CLt), and area under the plasma level-time curve (AUC) of vancomycin in normal volunteers using the compartment model dependent analysis were $0.150\pm0.030\;hr^{-1},\;32.9\pm2.81\;L/kg,\;5.36\pm0.63\;L/hr,\;and\;186.5\pm20.5\;{\mu}g/ml{\cdot}hr$, respectively. The $\beta$, Vd, CLt, and AUC of vancomycin in ovarian cancer patients using the compartment model dependent analysis were $0.109\;0.008\;hr^{-1},\;41.5\pm3.01\;L/kg,\;4.58\pm0.57\;L/hr\;and\;218.3\pm22.9\;{\mu}g/ml{\cdot}hr$, respectively. There were significant differences (p<0.05,\;p<0.01) in $\beta$, Vd, CLt, and AUC between normal volunteers and ovarian cancer patients. The elimination rate constant (Kel), CLt, and AUC of vancomycin in normal volunteers using the compartment model independent analysis were $0.152\pm0.022\;hr^{-1},\;5.77\pm0.75\;L/hr,\;and\;173.2\pm22.5;{\mu}g/ml{\cdot}hr$, respectively. The Kel, CLt, and AUC of vancomycin in ovarian cancer patients using the compartment model independent analysis were $0.126\pm0.012\;hr^{-1},\;4.96\pm0.55\;L/hr,\;and\;201.7\pm25.6;{\mu}g/ml{\cdot}hr$, respectively. There were significant differences (p<0.05, p<0.01) in Kel, CLt, and AUC between normal volunteers and ovarian cancer patients. And also, there was significant difference (p<0.05) in Kel of vancomycin in ovarian cancer patients between the compartment model dependent and independen analysis. It is necessary for effective dosage regimen of vancomycin in ovarian cancer patient to use these population parameters.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.17 no.3
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• pp.313-319
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• 2019

The A-KRS (Advanced Korean Reference Disposal System) is the disposal concept for pyroprocessed waste, which has been developed by the Korea Atomic Energy Research Institute. In this disposal concept, the amount of high-level radioactive waste is minimized using pyrochemical process, called pyroprocessing. The produced pyroprocessed waste is then solidified in the form of monazite ceramic. The final product of ceramic wastes will be disposed of in a deep geological repository. By the way, the decay heat is generated due to the radioactive decay of fission products and raises the temperature of buffer materials in the near field of radioactive waste repository. However, the buffer temperature must be kept below $100^{\circ}C$ according to the safety regulation. Usually, the temperature can be controlled by variation of the canister interdistance. However, KAERI has modelled thermal analysis under the boundary condition, where the waste canisters are in direct contact with each other. Therefore, a reliable temperature analysis in the disposal system may fail because of unknown thermal resistence values caused by the spatial gap between waste canisters. In the present work, we have performed thermal analyses considering the gap between heating elements and canisters at the beginning of canister loading into the radioactive waste repository. All thermal analyses were performed using the COMSOL software package.

• Childhood Kidney Diseases
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• v.7 no.2
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• pp.125-132
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• 2003

Purpose : Lipoprotein(a) is a genetically determined risk factor for atherosclerotic vascular disease and is elevated in patients with renal disease. Especially the patients with nephrotic syndrome exhibit excessively high Lp(a) plasma concentrations. Also the patients with end-stage renal disease have elevated Lp(a) levels. But the mechanism underlying this elevation is unclear. Thus, in this study, by measuring the level of serum Lp(a) in common renal diseases in children, we hoped to see whether there would be a change in Lp(a) in renal diseases other than nephrotic syndrome. Then, we figured out its implications, and looked for the factors that affect the Lp(a) concentrations. Methods : A total of 75 patients(34 patients with hematuria of unknown etiology, 10 with hematuria and hypercalciuria, 8 with IgA nephropathy, 8 with poststreptococcal glomerulone phritis, 3 with $Henoch-Sch\"{o}nlein$ nephritis, 7 with urinary tract infection, and 5 with or- thostatic proteinuria) were studied. The control group included 20 patients without renal and liver disease. Serum Lp(a), total protein, and albumin levels, 24-hour urine protein and calcium excretions, creatinine clearance and the number of RBCs and WBCs in the urinary sediment were evaluated. Data analysis was peformed using the Student t-test and a P-value less than 0.05 was considered to be statistically significant. Results : LP(a) was not correlated with 24-hour urine calcium and creatinine. Lp(a) level had a positive correlation with proteinuria and negative correlation with serum albumin and serum protein. Among the common renal diseases in children, Lp(a) was elevated only in orthostatic proteinuria (P<0.05). Conclusion : Lp(a) is correlated with proteinuria, serum protein, and serum albumin, but not with any kind of specific renal disease. Afterward, Lp(a) needs to be assessed in patients with orthostatic proteinuria and its possible role as a prognostic factor could be confirmed.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.2 no.2
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• pp.169-177
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• 1999

Purpose: To evaluate the efficacy of interferon alpha therapy with or without prednisolone in children with chronic hepatitis B. Methods: Twenty-eight children (22 boys, 6 girls, mean age 130 months) had seropositive results for HBsAg, HBeAg and HBV DNA; 11 had chronic persistent hepatitis and 17 had chronic active hepatitis. The patients were divided into two groups depending upon their inflammatory activity on liver biopsy, pretreatment serum ALT levels and HBV DNA levels. Fourteen children (group 1: chronic active hepatitis, ALT ${\geq}$ 100 IU/L and HBV DNA ${\leq}$ 100 pg/$300\;{\mu}L$) received interferon alpha 2a 5 $MU/m^2$ of body surface three times weekly for 6 months. Fourteen children (group 2: chronic persistent hepatitis or chronic active hepatitis with ALT < 100 IU/L or HBV DNA > 100 pg/$300\;{\mu}L$) received prednisolone in decreasing daily doses of 60 mg/$m^2$, 40 mg/$m^2$, and 20 mg/$m^2$, each for 2 weeks, followed after 2 weeks by interferon alpha 2a on the same schedule. At the end of therapy, 3 end points were analyzed: HBeAg seroconversion, serum ALT normalization rate and clearance of serum HBV DNA. Results: At the end of treatment, HBe antigen-to antibody seroconversion was higher but not more significant in group 1 than group 2 (71.4% vs. 50.0%). Only one patient in group 2 who lost HBeAg, also cleared HBsAg. ALT normalization was similar in both groups (64.3% in group 1 vs. 55.6% in group 2). Clearance of serum HBV DNA was observed in 78.6% of patients in group 1 and 64.3% in group 2, but no significant differences. Complete response was similarly achieved in both groups (57.1% in group 1 vs. 50.0% in group 2). Interferon alpha therapy with prednisolone priming was well tolerated and all children finished therapy. Conclusion: The combined therapy with prednisolone followed by interferon alpha may be safe and effective in inducing a serological and biochemical remission of the disease in approximately 50% of children with chronic hepatitis B and with a high level of viral replication and less active disease. However, a controlled study should be performed to confirm these results.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.62-69
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• 2000

Part of the locally applied, as well as the systemic applied, fluoride is absorbed into the body to aid in the prevention of caries. However, beyond a certain level, systemic distribution of fluoride can cause chronic fluorosis with attending systemic symptoms and dental fluorosis. Thus it is vital to determine the level of fluoride with minimal side effects which will provide optimal caries prevention. A commonly utilized method of regressively determining fluoride intade is to measure the fluoride concentration of excreted urine. Thus, the aim of this study was to determine the clearance time and concentration of fluoride in urine after administration of various doses of fluoride using HMDS-diffusion technique and fluoride ion electrode(Orion, 96-09, U.S.A.). Urine samples were collected in 7 adult subjects every morning after administration of fluoride supplements such as no fluoride(control group), 1mg fluoride(group 1), 2mg fluoride(group 2), 3mg fluoride(group 3), 4mg fluoride(group 4). The obtained results were as follows 1. Mean urinary fluoride concentration of control group was $0.707{\pm}0.362ppm$. 2. Fluoride levels followed as group 4(4.076ppm). group 3(2.400ppm), group 2(1.494ppm), group 1(1.051ppm) at day 1 after fluoride administration. There were no statistical differences between the urinary fluoride concentration of group 1, 2, 3 and control group after day 2, but there was statistical difference between group 4 and control group at day 2(p<0.05). 3. Urinary fluoride concentration increased and plateaued according to increasing fluoride dosage. The increased concentration remained significantly higher till day 2, but after day 3, there was no significant difference compared to the control.

• Childhood Kidney Diseases
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• v.5 no.2
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• pp.164-175
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• 2001

Purpose : Alport syndrome is a hereditary nephrotic disease characterized by progressive nephrotic symptom, sensorineural hearing loss, ophthalmic abnormality, typical microscopic findings, and familial occurrence. In this study, we tried to find the risk factors related with its prognosis by taking a close observation on clinical symptoms of children with Alport syndrome reviewing retrospectively. Materials & methods : We chose children diagnosed as Alport syndrome in renal biopsy during 20 years(from 1980, Jan. until 1999, Dec.) who could receive follow up studies in tile department of pediatrics. They were divided into two groups by comparing renal function at the time of diagnosis and at current status. We compared several clinical aspects in them, and applied nonparametric test for statistical analysis. Results : The sex ratio(male:female) of 24 children was 3:1. The most common clinical symptom presented at their first visit was gross hematuria. Among those 24 children, 11 cases($46\%$) of progressing into chronic renal failure(Group II) were observed. Hypertension, proteinuria and edema were seen much frequently in group II. The level of serum protein, albumin, and creatinine clearance were decreased while BUN, creatinine were relatively increased. All the results were statistically significant. Conclusion Clinically significant risk factors related to prognosis in Alport syndrome were the presence of hypertension, edema, and proteinuria at the time of diagnosis. Also, the level of serum protein, albumin, BUN, creatinine, and glomerular filtration rate were proved to be important factors in predicting prognosis. We believe that studies on these possible risk factors would be of great help in treating and predicting prognosis of children suffering with Alport syndrome. (J Korean Soc Pediatr Nephrol 2001;5 : 164-75)

• Archives of Pharmacal Research
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• v.28 no.3
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• pp.249-268
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• 2005

Drug metabolizing enzymes (DMEs) play central roles in the metabolism, elimination and detoxification of xenobiotics and drugs introduced into the human body. Most of the tissues and organs in our body are well equipped with diverse and various DMEs including phase I, phase II metabolizing enzymes and phase III transporters, which are present in abundance either at the basal unstimulated level, and/or are inducible at elevated level after exposure to xenobiotics. Recently, many important advances have been made in the mechanisms that regulate the expression of these drug metabolism genes. Various nuclear receptors including the aryl hydrocarbon receptor (AhR), orphan nuclear receptors, and nuclear factor-erythoroid 2 p45-related factor 2 (Nrf2) have been shown to be the key mediators of drug-induced changes in phase I, phase II metabolizing enzymes as well as phase III transporters involved in efflux mechanisms. For instance, the expression of CYP1 genes can be induced by AhR, which dimerizes with the AhR nuclear translocator (Arnt) , in response to many polycyclic aromatic hydrocarbon (PAHs). Similarly, the steroid family of orphan nuclear receptors, the constitutive androstane receptor (CAR) and pregnane X receptor (PXR), both heterodimerize with the ret-inoid X receptor (RXR), are shown to transcriptionally activate the promoters of CYP2B and CYP3A gene expression by xenobiotics such as phenobarbital-like compounds (CAR) and dexamethasone and rifampin-type of agents (PXR). The peroxisome proliferator activated receptor (PPAR), which is one of the first characterized members of the nuclear hormone receptor, also dimerizes with RXR and has been shown to be activated by lipid lowering agent fib rate-type of compounds leading to transcriptional activation of the promoters on CYP4A gene. CYP7A was recognized as the first target gene of the liver X receptor (LXR), in which the elimination of cholesterol depends on CYP7A. Farnesoid X receptor (FXR) was identified as a bile acid receptor, and its activation results in the inhibition of hepatic acid biosynthesis and increased transport of bile acids from intestinal lumen to the liver, and CYP7A is one of its target genes. The transcriptional activation by these receptors upon binding to the promoters located at the 5-flanking region of these GYP genes generally leads to the induction of their mRNA gene expression. The physiological and the pharmacological implications of common partner of RXR for CAR, PXR, PPAR, LXR and FXR receptors largely remain unknown and are under intense investigations. For the phase II DMEs, phase II gene inducers such as the phenolic compounds butylated hydroxyanisol (BHA), tert-butylhydroquinone (tBHQ), green tea polyphenol (GTP), (-)-epigallocatechin-3-gallate (EGCG) and the isothiocyanates (PEITC, sul­foraphane) generally appear to be electrophiles. They generally possess electrophilic-medi­ated stress response, resulting in the activation of bZIP transcription factors Nrf2 which dimerizes with Mafs and binds to the antioxidant/electrophile response element (ARE/EpRE) promoter, which is located in many phase II DMEs as well as many cellular defensive enzymes such as heme oxygenase-1 (HO-1), with the subsequent induction of the expression of these genes. Phase III transporters, for example, P-glycoprotein (P-gp), multidrug resistance-associated proteins (MRPs), and organic anion transporting polypeptide 2 (OATP2) are expressed in many tissues such as the liver, intestine, kidney, and brain, and play crucial roles in drug absorption, distribution, and excretion. The orphan nuclear receptors PXR and GAR have been shown to be involved in the regulation of these transporters. Along with phase I and phase II enzyme induction, pretreatment with several kinds of inducers has been shown to alter the expression of phase III transporters, and alter the excretion of xenobiotics, which implies that phase III transporters may also be similarly regulated in a coordinated fashion, and provides an important mean to protect the body from xenobiotics insults. It appears that in general, exposure to phase I, phase II and phase III gene inducers may trigger cellular 'stress' response leading to the increase in their gene expression, which ultimately enhance the elimination and clearance of these xenobiotics and/or other 'cellular stresses' including harmful reactive intermediates such as reactive oxygen species (ROS), so that the body will remove the 'stress' expeditiously. Consequently, this homeostatic response of the body plays a central role in the protection of the body against 'environmental' insults such as those elicited by exposure to xenobiotics.

• Childhood Kidney Diseases
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• v.5 no.2
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• pp.136-146
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• 2001

Purpose : One of the most difficult problems in the care of children with nephrotic syndrome remains the occurrence of relapses, despite initial response to steroids. Constantinescu reported that rapidity of initial response to steroid therapy could predict fewer relapses in the first year. So we evaluated the changes in serum lipid abnormalities in children with corticosensitive nephrotic syndrome before steroid treatment and the correlation between serum lipid levels and renal function, days to remission. Methods . We analyzed the Medical records of children who were managed by us between October 1994 and August 2000. In 33 patients with corticosensitive nephrotic syndrome, we evaluated the correlation between serum lipid levels and renal function [Creatinine clearance(Ccr)] and proteinuria before steroid treatment, and days to remission defined as the third day when the patient's urine becomes protein free. Results : There were 21 males and 12 females. Median age at presentation was 6.4 years (range: 1.8-17.3 years). Median days to remission were 15.4 days (range 4-42 days) on Prednisolone $60mg/m^2$ daily. The increased levels of triglyceride, total cholesterol, LDL cholesterol, apolipoprotein B, total cholesterol/HDL cholesterol, Lipoprotein(a) were observed. But the level of HDL cholesterol was not increased. Serum albumin was decreased a]id proteinuria was increased before steroid treatment. But Ccr was not decreased. There were negative correlation between serum albumin and total cholesterol (r = -0.5157, P<0.005), LDL cholesterol (r = -0.5543, P<0.005), total cholesterol/HDL cholesterol (r = -0.4506, P<0.01), lipoprotein(a) (r = -0.4570, P<0.025), apolipoprotein B (r = -0.5297, P<0.025), apolipoprotein B/apolipoprotein Al (r = -0.5851, P<0.01), apolipoprotein B/HDL cholesterol (r = -0.4961, P<0.05) before steroid treatment. There was no correlation between proteinuria and serum lipid profiles. Also Ccr and serum lipid profiles were not correlated. There was positive correlation between days to remission and HDL cholesterol (r = +0.4511, P<0.05), apolipoprotein B (r = +0.5190, P<0.05), apolipoprotein B/HDL cholesterol (r = +0.7169, P<0.005). Conclusions : This results reveal that HDL cholesterol, apolipoprotein B and apolipoprotein B/HDL cholesterol can be used as a predictive factor in corticosensitive nephrotic syndrome. We could not determine the significant level of these lipids for insufficient patients number, but these level may predict future relapses of corticosensitive nephrotic syndrome patients and thus may allow to better management and treatment protocols. More data and long term follow up studies should be needed. (J Korean Soc Pediatr Nephrol 2001;5 : 136-46)

• Journal of Korean Society of Transportation
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• v.18 no.4
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• pp.51-62
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• 2000

The objective of this study was to reevaluate current Korean design values for lane width widenings on horizontal currie sections and to develop a new method for derivation of design values based on low-speed offtracking. For this purpose, earlier research were reviewed and necessary equations were derived. Also, the method for derivation of widening values of Korea was compared with that for other countries. The result showed that present Korean method could not consider the variation of lane widths and design speeds of roads. In this Paper, to solve such problems, the new concept of widening was developed. That is the current concept of widening which concerns only the dimension of vehicles and radius of curves was replaced by a new concept that lane width widenings on horizontal curve sections is the difference between the width required on curries and tangents. The width required on a curve consists of the swept Path of a vehicle, lateral clearance, and additional allowance. The width of a tangent is calculated by multiplying lane width by the number of lanes The result of applying new concept shows that the values derived from new concept are higher than current design values for curries have same radius. This study was based only on low-speed offtracking. Therefor, it is recommended that further studies which consider the superelevation and high-speed effect on offtracking be made to derive more accurate widening values .