• The KSFM Journal of Fluid Machinery
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• v.18 no.2
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• pp.22-28
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• 2015

The primary design goal of a compressor is focused on improving efficiency. Secondary objective is to widen the operating range of compressor. This paper presents a numerical and experimental investigation of the influence of the bleed slot on the operating range for the 1.2 MW class centrifugal compressor installed in a turbocharger. The main design parameters of the bleed slot casing are upstream slot position, inlet pipe slope, downstream slot position and width. The DOE(design of experiment) method was carried out to optimize the casing design. Numerical analyses were done by the commercial code ANSYS-CFX based on the three dimensional Reynolds-averaged Navier-Stokes equations. Results showed that efficiency and pressure ratio increased as the downstream slot position and width were smaller and the upstream position was located away from the impeller inlet. Experimental works were also done with and without the bleed slot casing. The simulation results were in good agreement with the test data. Enhancement of both the surge margin up to 26.5% and the pressure ratio with the optimized bleed slot design were achieved, compared with the surge margin of only 6.6% without the bleed slot casing.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.11
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• pp.1216-1223
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• 2014

Internet traffic is rapidly increasing due to the spread of personal smart devices and the demand for multimedia contents. When designing a large ship such as cruise, network architecture is also considered which supports various IT services in a maritime environment similar to the ground environment. In this paper, we consider wireless P2P (peer-to-peer) communication for efficient multimedia content sharing and propose novel handover scheme for efficient download service. The proposed handover method shows that it can improve the download symbol rates for handover in a wireless P2P system considering the signal strength and quality of peers as well. The proposed system is expected to provide efficient contents distribution and reliable communication in the ship-area-network (SAN).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.11
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• pp.1042-1049
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• 2014

In Military MicroWave communication, the distance of link, availability, transmission capacity is the important point in order to design the circuit. Currently, operated by fixed modulation, in the future it will be evolved to the modulation techniques enabled to increase the transmission capacity. It would be hard to consistently guarantee the transmission quality of the high-availability because the occurrence probability of fading increase in terms of the link distance for the case of the long distance. In the case of the modulation techniques for the transmission of high-capacity, as the distance is long, a falling-off in the fade margin from the link budget analysis cause the decrease in the availability. It is difficult to provide QoS guaranteed connection. In this paper, we propose the performance improvement technique of transmission by the variable allocation of the bandwidth and the higher priority transmission technique using setting the ratio of the higher priority capacity in association with the distance of link. Also we suggest the alternative of the calculation for channel transmission capacity to design the circuit.

• Journal of Society of Preventive Korean Medicine
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• v.14 no.3
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• pp.27-35
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• 2010

Objective : This study was carried out to investigate the acute toxicity and safety of Insampaedok-san extract in ICR Mice. Methods : SPF ICR male and female mice were administered orally with Insampaedok-san extract of 0 (control group), 1250, 2500 and 5000 mg/kg. After single administration, we daily examined number of deaths, clinical signs, gross findings and changes of body weight for 14 days. Hematological parameters and isolated organ weights were determined after 14 days of administration. Results : No dead animal and no significant changes of body weights were found during experimental period. In addition, no differences were found between control and all of treated groups in clinical signs, organ weights and hematology, and other findings. Conclusions : Insampaedok-san extract did not show any toxic effects and oral LD50 values of the extracts was over 5000 mg/kg in ICR mice.

• Journal of Navigation and Port Research
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• v.40 no.3
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• pp.139-146
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• 2016

Due to the continuous increasement of the container cargoes, each container port market has been growing as well. Moreover, the competition among container terminal operators located in the same port is also growing in order to attract more container cargoes. This paper looked into the market structures, market conducts and market performances of container ports in Busan and Shanghai. The index which has been most widely used to measure market structure, the Hirschman-Herfindahl Index (HHI), is computed by squaring each supplier's market share, then adding the squared shares. This paper estimated the market performance as profitability (PCM, ROA), growth (total TEU, rate of the increasement of TEU) and examined the effects of the HHI on the profitability and growth in a container terminal operators in Korea and China. The major findings of this study is that the market structure has effects on market performance in Busan port (total TEU) and Shanghai port (PCM, ROA and total TEU). As a result of analysing this study, market structure has an effect on market performance in Busan and Shanghai port, but the power of influence can be changed by market concentration index and various market conduct of companies.

• Korean Journal of Oriental Medicine
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• v.4 no.1 s.4
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• pp.115-127
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• 1998

To improve the quality control of frequently used oriental medicinal plants, the storage, cutting, processing and decokting methods of Rehmannia glutinosa Libosch. var. purpurea Makino(熟地黃) were examined. The contents of 5-hydroxymethyl-2- furaldehyde(5-HMF) of Rehmannia glutinosa Libosch. var. purpurea Makino were analysed by HPLC at various conditions as the standard component. Raw materials were classified into 3 groups with their specific gravity(天 地 人黃) and determined the ding weights and the contents of water, the solid component of Ji-Hwang(地黃) was the most. Rehmannia glutinosa Libosch. var purpurea Makino was steamed and dried nine times and analysed the content of 5-HMF on every time. In the case of Ji-Hwang, the standard component of the ninth sample was produced the most. But which of the tenth samples of Chun-Hwang and Yin-Hwang(天黃 人黃) were the most. The best decokting conditions which were determined by the yield of 5-HMF were as follows : non cutting, soaking time was 0 minutes, decokting time was 75 minutes after boiling. The contents of sugar on each of samples were determined. The contents of standard component increased by steaming number and the contents of sugar decreased.

• Korean Journal of Oriental Medicine
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• v.17 no.3
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• pp.115-121
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• 2011

Objective : The purpose of this study was to investigate the changes in the contents of constituents in Socheongryong-tang (CY) and its fermentations (FCY) with 10 species of lactic acid bacteria. Methods : Ten strains of lactic acid bacteria, Lactobacillus casei 127, L. acidophilus 128, L. casei 129, L. plantarum 144, L. amylophilus 161, L. curvatus 166, L. delbruekil subsp. lactis 442, L. casei 693, B. breve 744, and B. thermophilum 748, were used for the fermentation of Socheongryong-tang. The increased and decreased constituents were identified using HPLC/DAD and various liquid chromatographic techniques, and the structure was elucidated using NMR and MS. These compounds were quantitatively analyzed using an HPLC/DAD system. Results : The increased constituents were identified to be liquiritigenin (1) and cinnamyl alcohol (2), and the decreased constituent was determined to be liquiritin (3). Liquiritigenin (1) and cinnamyl alcohol (2) were increased in all of the FCYs, while liquiritin (3) was decreased. The fermentation of the ten lactic acid bacteria demonstrated that the decomposable rate of these three compounds in FCYs were different. Socheongryong-tang fermented by L. plantarum 144 and L. amylophilus 161 showed the most remarkable changes. Conclusions : CY could be increased antibacterial, neuroprotective, or antiinflammatory effect by fermentation with lactic acid bacteria, especially with L. plantarum and L. amylophilus, considering their known biological activities. In addition, it is expected that this study will help to establish quality control parameters for FCY.

• Korean Journal of Oriental Medicine
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• v.16 no.1
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• pp.173-178
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• 2010

The purpose of this study was investigation of quantitative analysis of marker substances in solid fermented Angelicae Gigantis Radix by High performance liquid chromatography(HPLC). HPLC was performed for determination of nodakenin and decursin in solid fermented Angelicae Gigantis Radix extract, the separation method was performed on C18 column ($250\;mm\;{\times}\;4.6\;mm$, $5\;{\mu}m$, RS tech) using gradient solvent mixtures of water-acetonitrile with photodiode array detector (330 nm). The flow rate was 1.0 ml/min. Retention time of nodakenin and decursin was about 11.47, 46.79 min and linearity of calibration was showed good result(r2=0.9999, 0.9999), respectively. Content of nodakenin was $0.76\;{\pm}\;0.02%$ in control, $0.31\;{\pm}\;0.00%$ in Angelicae Gigantis Radix extract fermented with Paecilomyces japonica(SDT)(p<0.01), $0.51\;{\pm}\;0.02%$ in Angelicae Gigantis Radix extract fermented with Ganoderma lucidum(SYT)(p<0.01), $0.82\;{\pm}\;0.03%$ in Angelicae Gigantis Radix extract fermented with honey(SST)(p<0.05) and $0.88\;{\pm}\;0.01%$ in Angelicae Gigantis Radix extract fermented with Nuruk(SNT)(p<0.01). Content of decursin was $4.50\;{\pm}\;0.08%$ in control, $2.90\;{\pm}\;0.05%$ in Angelicae Gigantis Radix extract fermented with Paecilomyces japonica(SDT)(p<0.01), $2.65\;{\pm}\;0.08%$ in Angelicae Gigantis Radix extract fermented with Ganoderma lucidum(SYT)(p<0.01), $4.46\;{\pm}\;0.11%$ in Angelicae Gigantis Radix extract fermented with honey(SST) and $4.73\;{\pm}\;0.04%$ in Angelicae Gigantis Radix extract fermented with Nuruk(SNT)(p<0.05), respectively.

• Korean Journal of Oriental Medicine
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• v.16 no.1
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• pp.149-155
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• 2010

Objective : Ssangwha-tang is a traditional medicine formula widely prescribed for a decrease of fatigue after an illness in Korea. The aim of this study is to investigate the effect of Ssangwha-tang fermented by Lactobacillus fermentum (SF) on osteoclast differentiation in vitro and on bone metabolism of an ovariectomized rat in vivo. Methods : Tartrate-resistant acid phosphatase activity and staining were applied to evaluate the formation of osteoclasts. Ovariectomized rats were orally administrated with SF (30 ml/kg/day) for 12 weeks. Serum aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, triglyceride, phosphate, calcium levels were determined. Effect of SF on bone loss were studied by histological analysis and the measurement of bone mineral density. Results : SF significantly inhibited tartrate-resistant acid phosphatase activity and formation of osteoclasts in RAW264.7 cells stimulated by receptor activator for nuclear factor ${\kappa}B$ (NF-${\kappa}B$) ligand (RANKL). In addition, SF significantly decreased the level of triglyceride and increased the level of low-density lipoprotein. Moreover, the decrease of trabeculae of the femur was partially prevented in ovariectomized rats administrated with SF. Conclusions : SF treatment could prevent ovariectomy induced bone loss and its effects could be medicated by the inhibition of osteoclastogenesis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.1A
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• pp.1-8
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• 2007

In this paper, we have derived the Noise-Equation to determine the level of cross-modulation noise that is required for designing multi-band CDMA handset from IS-98 standard. From this Noise-Equation, also we were able to determine each component's specification and forecast the performance(or margin) of designing handset. In conclusion, we have designed and implemented the multi-band CDMA handset of Qualcomm's Zero-IF structure and verified validity of the Noise-Equation. In result, we have got the result of ${\pm}0.5dB$ error between Noise-Equation and actual measurement. Therefore, this paper will give a guideline for design of the Multi-Band CDMA handset.