• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.03a
• /
• pp.330-339
• /
• 2008

Ground-based interceptors(GBI) comprise a major element of the strategic defense against hostile targets like Intercontinental Ballistic Missiles(ICBM) and reentry vehicles(RV) dispersed from them. An optimum design of the subsystems is required to increase the performance and reliability of these GBI. Propulsion subsystem design and optimization is the motivation for this effort. This paper describes an effort in which an entire GBI missile system, including a multi-stage solid rocket booster, is considered simultaneously in a Genetic Algorithm(GA) performance optimization process. Single goal, constrained optimization is performed. For specified payload and miss distance, time of flight, the most important component in the optimization process is the booster, for its takeoff weight, time of flight, or a combination of the two. The GBI is assumed to be a multistage missile that uses target location data provided by two ground based RF radar sensors and two low earth orbit(LEO) IR sensors. 3Dimensional model is developed for a multistage target with a boost phase acceleration profile that depends on total mass, propellant mass and the specific impulse in the gravity field. The monostatic radar cross section (RCS) data of a three stage ICBM is used. For preliminary design, GBI is assumed to have a fixed initial position from the target launch point and zero launch delay. GBI carries the Kill Vehicle(KV) to an optimal position in space to allow it to complete the intercept. The objective is to design and optimize the propulsion system for the GBI that will fulfill mission requirements and objectives. The KV weight and volume requirements are specified in the problem definition before the optimization is computed. We have considered only continuous design variables, while considering discrete variables as input. Though the number of stages should also be one of the design variables, however, in this paper it is fixed as three. The elite solution from GA is passed on to(Sequential Quadratic Programming) SQP as near optimal guess. The SQP then performs local convergence to identify the minimum mass of the GBI. The performance of the three staged GBI is validated using a ballistic missile intercept scenario modeled in Matlab/SIMULINK.

• Journal of Environmental Science International
• /
• v.14 no.2
• /
• pp.121-128
• /
• 2005

Hexachlorobenzene (HCB) was analyzed in various marine organisms of Korea. HCB was detected in all organism samples with residual concentrations from 0.51 to 222 pg/g wet weight. HCB residue was the highest content in crustacean, and followed by bivalves, fish, cephalopods and gastropods. The residues were comparable to or lower than those in marine organisms of other countries. Daily dietary intake of HCB from seafood was estimated to be 13.4 pg/kg body weight/day. The relative contribution of taxonomic group to the total dietary intake of HCB were in the order of crustaceans $(40.1\%)$, bivalves $(34.2\%)$, fish $(23.1\%)$, cephalopods $(2.22\%)$, and gastropods $(0.38\%)$. Daily dietary intake of HCB expressed as toxic equivalent (TEQ) value was estimated to be $1.34\times10^{-3}pg$ TEQ/kg body weight/day. This value did not exceed tolerable daily intake (TDI) proposed by the WHO, the UK toxicity committee and the KFDA. Cancer risk and target hazard quotient (THQ) due to the consumption of the marine organism in Korean adult population were evaluated using the exposure equation of food ingestion. This result suggests that dietary intake of HCB by the consumption of Korean seafood seems to be safe for human health with negligible cancer and non-cancer risks so far.

• Development and Reproduction
• /
• v.1 no.2
• /
• pp.125-132
• /
• 1997

To investigate the cadmium (Cd) toxicity on the testis, male rats were treated with 1, 2, 4 and 8 mg/kg of Cd by IP. According to histochemical studies, Cd-treated testis tissue showed death of spermatozoa, death of Sertoli cells, death of all the spermatogenic cells, and finally disappearance of basal lamina of seminiferous tubules with increasing doses, and showed decreased ground substances and Leydig cells, increased inflammatory cells and fibroblasts, and fibroblasts, and finally disappearance of ground substances and all the cells except fibroblasts within interstitial tissues with increasing doses. According to biochemical studies, two kinds of proteins, 25 and 45 kDa, were dramatically disappeared from the total protein of rat testis treated with Cd comparing to normal testis. The result of electrophoresis of total protein suggests that actin (45 kDa), presumed on its mmolecular weight and amount, in the testis-cells is the primary target of Cd poisoning. Although its exact mechanism is not clear, the disappearance of two proteins when testis is exposed to Cd should give some clues to understnad the mechanism of necrosis of testis tissue crumbling by heavy metal pollutant such as Cd.

• Korean Journal of Environmental Biology
• /
• v.22
• /
• pp.78-85
• /
• 2004

Polyeyclic aromatic hydrocarbons (PAHs) were quantitatively determined in bivalves from Gwangyang Bay. Twenty-four kinds of target PAHs were detected in the entire samples. Total PAHs concentrations ranged 86.1∼1,210 ng g$\^$-1/ dry weight with a average concentration of 309 ng g$\^$-1/, which is much lower than those of other industrialized bays in Korea. Strong tidal currents and artificial interferences like reclamation and dredging activity were suggested as major reason for disparity between highly industrialization and low contamination status. There was no correlation between total PAHs and lipid contents, implying that lipid content is not the one major parameter for the accumulation of PAHs by bivalves. Input sources were inferred as petrogenic and pyrogenic PAHs. With help of PCA analysis, signals of seasonal variations, not only concentrations but also compositions were found.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.25 no.2
• /
• pp.178-188
• /
• 2019

When using a distributed system, it is very important to know the intention of a target ship in order to prevent collisions. The action taken by a certain ship for collision avoidance and the action of the target ship it intends to avoid influence each other. However, it is difficult to establish a collision avoidance plan in consideration of multiple-ship situations for this reason. To solve this problem, a Distributed Stochastic Search Algorithm (DSSA) has been proposed. A DSSA searches for a course that can most reduce cost through repeated information exchange with target ships, and then indicates whether the current course should be maintained or a new course should be chosen according to probability and constraints. However, it has not been proven how the parameters used in DSSA affect collision avoidance actions. Therefore, in this paper, I have investigated the effect of the parameters and weight factors of DSSA. Experiments were conducted by combining parameters (time window, safe domain, detection range) and weight factors for encounters of two ships in head-on, crossing, and overtaking situations. A total of 24,000 experiments were conducted: 8,000 iterations for each situation. As a result, no collision occurred in any experiment conducted using DSSA. Costs have been shown to increase if a ship gives a large weight to its destination, i.e., takes selfish behavior. The more lasting the expected position of the target ship, the smaller the sailing distance and the number of message exchanges. The larger the detection range, the safer the interaction.

• Journal of Korean Medicine Rehabilitation
• /
• v.21 no.1
• /
• pp.1-22
• /
• 2011

Objectives : This study was undertaken to verify the effects of Wolbigachul-tang1(WBCEx1) on obesity using high fat diet-induced male mice and to investigate the molecular mechanisms involved. Methods : 8-week old C57BL/6 mice were divided into 5 groups; lean control, obese control, WBCEx1, 2, 3. After mice were treated with WBCEx1(water extract), 2(30% ethanol extract), 3(water extract; Ephedra sinica Stapf., Gypsum fibrosum) for 12 weeks, body weight gain, feeding efficiency ratio, plasma lipid and glucose metabolism, the messenger RNA(mRNA) expression of peroxisome proliferator activated receptor(PPAR)$\alpha$ target genes were measured. In addition, $PPAR{\alpha}$ target gene expression was examined in liver, white adipose tissue and skeletal muscle. Results : 1. WBCEx1-treated mice had significantly lower body weight gain and feeding efficiency ratio. 2. Consistent with the effects on body weight gain, WBCEx1 decreased the weights of epididymal and retroperitoneal white adipose tissue, inguinal subcutaneous adipose tissue, and brown adipose tissue. 3. WBCEx1 significantly decreased plasma triglyceride and total cholesterol levels. 4. The size of adipocytes were significantly decreased by WBCEx1, whereas the adipocyte number per unit area was increased. Hepatic lipid accumulation was decreased by WBCEx1. 5. WBCEx1 did not affect the mRNA expression of $PPAR{\alpha}$ target genes in liver, adipose tissue, and skeletal muscle. 6. Plasma asparate aminotransferase(AST), alanine aminotransferase(ALT), blood urea nitrogen(BUN) and creatine concentrations were in the physiological range. Liver and kidney weights were significantly lower following WBCEx treatment compared with obese controls, indicating that WBCEx does not show any toxic effects on liver and kidney. Conclusions : These results suggest that WBCEx1-induced body weight reduction is associated with appetite control and mediated by a mechanism other than the activation of $PPAR{\alpha}$.

• BMB Reports
• /
• v.45 no.3
• /
• pp.141-146
• /
• 2012

Protein tyrosine phosphatase 1B (PTP1B) is important in the regulation of metabolic diseases and has emerged as a promising signaling target. Previously, we reported the PTP1B inhibitory activity of Rheum undulatum (RU). In the present study, we investigated the metabolic regulatory effects of RU in a high-fat diet (HFD) model. RU treatment significantly blocked body weight gain, which was accompanied by a reduction of feed efficiency. In addition, it led to a reduction of liver weight mediated by overexpression of PPAR${\alpha}$ and CPT1 in the liver, and an increase in the expression of adiponectin, aP2, and UCP3 in adipose tissue responsible for the reduction of total and LDL-cholesterol levels. Chrysophanol and physcion from RU significantly inhibited PTP1B activity and strongly enhanced insulin sensitivity. Altogether, our findings strongly suggest that 2 compounds are novel PTP1B inhibitors and might be considered as anti-obesity agents that are effective for suppressing body weight gain and improving lipid homeostasis.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.42 no.3
• /
• pp.167-175
• /
• 2019

The purpose of this study is to analyze the factors influencing consumers purchasing of domestic, imported and craft beer through AHP analysis and to provide implications for marketing for each beer market. In this study, theories and calculations related to AHP analysis were thoroughly examined and selection attributes were determined by referring to existing theories. A total of 164 consumers who have purchased beer were the target of the survey. The results were analyzed by AHP analysis and the differences were analyzed. It was confirmed that the domestic, imported, and craft beer had the highest weight in the taste in the first layer. At this time, we can confirm that imported, and craft beer has a relatively high weight on taste and domestic beer has a relatively high weight on brand image. We also found that design and advertising images do not have a significant impact on beer selection. Even though it is study on beer, we can find people have different preference between their orgin. In this study, it is possible to show what type of factors does the beer manufacturing and distribution company should concentrate on by analyzing factors that consumers consider, unlike other studies focusing on consumption status of existing beer.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.37 no.3
• /
• pp.174-180
• /
• 2001

Dusky spinefoot, Siganus fuscescens live primarily in shore reefs with sea weeds, like around Jeju Island in Korean south sea. Therefore they are caught much by set net in the coast of Jeju Island. We carried out measurements of the dorsal aspect target strengths of Dusky spinefoot in order to study the influences of swim bladder for fishes. and have obtained some desired results though not sufficiently complete as comparison with target strengths of fishes before and after the air gas in the swim bladder of fish is taken off by an injector. The appropriate equations share the common form TS = A + 20 log L. TS = B + 20/3 log W where TS is the average dorsal aspect target strength in decibels. L is the fish total length in centimeters. W is the fish total weight in grams, and the coefficient A and B are determined by a least mean squares regression analysis. The results obtained before the air gas in the swim bladder of fish is taken off are TS = -63.16 + 20 log L TS = -50.50 + 20/3 low W and, the results obtained after the air gas in the swim bladder of fish is taken off are TS = -65.29 + 20 log L TS = -52.62 + 20/3 log W As above result, the differences of target strengths before and after the air gas is taken off from swim bladder are 2.12-2.13 dB, but the maximum difference of target strengths of both cases averaged according to the fish aspects from $-45^\circ$ to $45^\circ$ is 5.87 dB, and the average difference of them is 2.01 dB.

• Biomolecules & Therapeutics
• /
• v.12 no.1
• /
• pp.49-54
• /
• 2004

The present study was conducted to investigate the potential subacute toxicity of CKD-602 by a 5-day repeated intravenous administration in Sprague-Dawley rats. CKD-602 was administered intravenously to male rats at dose levels of 0, 0.08, 0.2, and 0.5 mg/kg for 5 days. Studies included general observation, body weight changes, ophthalmoscopic examination, hematology, se겨m biochemistry, gross findings at necropsy and organ weight measurement. There were no deaths in any treatment group and treatment related clinical sign was depilation in the 0.5 mg/kg groups. The decrease or suppression of body weight was also observed dose-dependently in all treatment groups. Decreased leukocyte in all treatment groups, decreased platelet in the above 0.2 mg/kg groups and increase in the serum levels of total cholesterol in the 0.5 mg/kg group were considered as a treatment related toxic effects. Decreased weight of thymus in all treatment groups anti decreased weight of spleen in the above 0.2 mg/kg group were observed. The intravenous administration of CKD-602 caused depilation and decreased weight and had toxic effect on the leukocyte, platelet, spleen and thymus. In the condition of this study, the target organs were spleen and thymus and the toxic effect level was determined to be 0.2 mg/kg, but no-observed-adverse-effect level (NOAEL) was considered to be lower than 0.08 mg/kg.