• Transactions of the KSME C: Technology and Education
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• v.4 no.1
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• pp.35-41
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• 2016

Geothermal heat pump (GHP) systems have been proved to be one of the most efficient systems for heating and cooling in buildings. However, an optimal energy performance depends on a good control of the system components, including heat pumps and circulation pumps, which affect to the total energy consumption of system. This paper presents the simulation results of the heat pump performance for two different control schemes, i.e. constant setting temperature (Control-A) and variable setting temperatures (Control-B) in buffer tank. A dynamic simulation tool, TRNSYS 17, was used to model the entire system and to assess the performance of the system. Simulation results show that the Control-B, which controls the temperature in buffer tank with outdoor air temperature, is a effective way to reduce the energy consumptions in heat pump (7.7%) and circulation pump (7.5%).

• Journal of IKEEE
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• v.20 no.2
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• pp.188-191
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• 2016

In this paper, we propose energy-efficient automatic power controller which can power on and off the signboard at the specified light intensity using the Illuminance Detector. By using segmented section Classification algorithm, light intensity setup system propose variable resistor method which makes users more easy to control. Automatic light on-off system set a standard by measured illuminance data. Measured light-intensity through the Illuminance Detector are communicated with the signboard power controller with wireless communication, and it controls lighting system. In this paper, we evaluated the Energy-Efficient Automatic Power Controller of The Signboard using illuminance detector. Experimental results in lightless environment shows that the error rate is less than 3% by Accredited Testing Laboratories.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.2 s.245
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• pp.110-116
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• 2006

A syringe pump or a device using high electric voltage has been used for controlling flows inside a LOC (lab-on-a-chip). Compared to LOC, however, these microfluidic devices are large and heavy that they are burdensome for a portable ${\mu}-TAS$ (micro total analysis system). In this study, a new flow control technique employing pressure regulators and pressure chambers was developed. This technique utilizes compressed air to control the micro-scale flow inside a LOC, instead of a mechanical actuator or an electric power supply. The pressure regulator controls the output air pressure by adjusting the variable resistor attached. We checked the feasibility of this system by measuring the flow rate inside a capillary tube of $100{\mu}m$ diameter in the Re numbers ranged from 0.5 to 50. In addition, the performance of this flow control system was compared with that of a conventional syringe pump. The developed flow control system was found to show superior performance, compared with the syringe pump. It maintains automatically the: air pressure inside a pressure chamber whether the flow inside the capillary tube is on or off. Since the flow rate is nearly proportional to the resistance, we can control flow in multiple microchannels precisely. However, the syringe pump shows large variation of flow rate when the fluid flow is blocked in the microchannel.

• Journal of Periodontal and Implant Science
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• v.24 no.2
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• pp.397-405
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• 1994

Minocline Strip(MS), a local drug delivery developed as a controlling means for microoragnisms in gingival wound and periodontitis, was implanted in the gingiva of experimental animals. The toxic effects and biodegradation of MS were studied in respect to pathological changes induced in gingival tissue. The experimental animals treated with MS had not showed significant difference in symptom, body weights, feed and water intake, and blood analysis throughout 150 days of experimental period, but revealed significantly increased values of total WBC counts and AST (SGOT) on the 7th day, compared with controls. The treated animals revealed petechial hemorrhage and severe edema accompanying degeneration and necrosis of damaged muscle fibers around the surgical wound, but no local inflammatory reaction and concerned lesions were found. The implanted MS became encapsulated by thin connective tissue, and its size and color diminished gradually according to the experimental term. The MS-like material appeared in the nearby lymphatics on the 110th day. The implated MS remained as fine granular particles or disappeared on the 130th day, and the decrease of its volume and density were variable depending on each individual. These results indicate that long-term implantation of MS may not produce inflammation or toxic effects, and eventually lead to complete biodegradation.

• Journal of Preventive Medicine and Public Health
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• v.49 no.2
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• pp.97-107
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• 2016

Objectives: Research on how the risk of gastric cancer increases with Epstein-Barr virus (EBV) infection is lacking. In a systematic review that investigated studies published until September 2014, the authors did not calculate the summary odds ratio (SOR) due to heterogeneity across studies. Therefore, we include here additional studies published until October 2015 and conduct a meta-analysis with meta-regression that controls for the heterogeneity among studies. Methods: Using the studies selected in the previously published systematic review, we formulated lists of references, cited articles, and related articles provided by PubMed. From the lists, only case-control studies that detected EBV in tissue samples were selected. In order to control for the heterogeneity among studies, subgroup analysis and meta-regression were performed. Results: In the 33 case-control results with adjacent non-cancer tissue, the total number of test samples in the case and control groups was 5280 and 4962, respectively. In the 14 case-control results with normal tissue, the total number of test samples in case and control groups was 1393 and 945, respectively. Upon meta-regression, the type of control tissue was found to be a statistically significant variable with regard to heterogeneity. When the control tissue was normal tissue of healthy individuals, the SOR was 3.41 (95% CI, 1.78 to 6.51; I-squared, 65.5%). Conclusions: The results of the present study support the argument that EBV infection increases the risk of gastric cancer. In the future, age-matched and sex-matched case-control studies should be conducted.

• The KIPS Transactions:PartC
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• v.15C no.6
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• pp.547-556
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• 2008

Recently, with the advance of computing and networking technique, the high speed internet becomes widespread, however, it is still hard job to do streaming the media which requires high network bandwidth over the internet. Previous researches for streaming over the internet mainly proposed techniques that controls the QoS(Quality of Service) of the media in proportion to the network status. Though, this could be the solution for the service provider while the service user who wants constant QoS may not satisfy with variable QoS. In the paper, we propose a network adaptive prefetching technique, NAP, for guarantee of constant QoS. The NAP prefetches frames by increasing the frame transmission rate while the available network bandwidth is high. The NAP uses the prefetched frames to guarantee the QoS while the available network bandwidth is low. The experiment result shows that the proposed NAP could guarantee the constant QoS by prefetching the frames adaptively to the network bandwidth with the characteristic of video stream.

• Korean Journal of Biological Psychiatry
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• v.16 no.4
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• pp.238-245
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• 2009

Objectives : Mild Alzheimer's disease(AD) is uncertain to be related to visuospatial working memory subsystem dysfunction. We used the self ordered pointing test(SOPT) to find the characteristics of visuospatial working memory in mild AD. Methods : We compared the visuospatial working memory abilities of 20 patients with mild AD and 20 normal elderly controls(NC) using SOPT, of which stimuli consisted of two stimuli types(A : abstract, C : concrete) and two stimuli numbers(8 and 12). Therefore, working memory was tested using C8, C12, A8, and A12 stimuli conditions in SOPT. Mixed-model ANOVA was conducted with the AD and NC groups as between-subjects factor, with stimuli types and stimuli numbers as the within-subjects factors and with SOPT error rates as the dependent variable. Results : The AD group showed higher error rates in SOPT than the NC group. The NC group showed low error rates in concrete stimuli than in abstract stimuli and in small stimuli numbers than in large stimuli numbers. And the AD group showed no differences between stimuli types or stimuli numbers. Conclusion : AD patients showed a poor performance in visuospatial working memory using concrete stimuli. The result suggests that there is a non-transformation from visual input to phonological working memory in AD. Patients with AD showed a poor performance although in small stimuli number condition of SOPT. It suggests that in AD, visuospatial working memory is not working well although in low central executive loads.

• Radiation Oncology Journal
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• v.8 no.2
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• pp.151-154
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• 1990

The acute effects of variable dos rates to total body irradiation (TBI) were investigaed with 600 cGy of single exposure in the mice as a preclinical model. Total 80 mice (ICR) were used. Twenty of which sewed as controls, receiving no irradiation. All irradiated mice showed a universal decline in their weight and white blood cell count. The degree of weight loss and leukopenia were similar at 3 different dos rate but slightly prominent with 15 cGy/minute group. The degree of recovery among the groups showed no dose rate dependence. Our results suggest that TBI with 15 cGy/mimute may be applicable for clinical therapy with careful evaluation of patient's condition.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.16
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• pp.6721-6726
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• 2014

Background: The aim of this preliminary study was to address variations of responses observed with different starting tumor sizes of 10 and 15 mm, and the effects of different doses of tamoxifen (TAM) on experimental rat mammary tumors. Materials and Methods: Thirty-five inbred female Sprague Dawley rats aged 43 days were administered with three weekly doses of N-methyl-N-nitrosourea (NMU) intraperitoneally (ip) at 50 mg/kg body weight. Animals were randomized (beginning from 10 mm tumor size) into four TAM-treated (50, 100, 200 and $500{\mu}g/day$) groups of six animals each, and another group (n=6) treated with TAM $100{\mu}g/day$ at starting tumour size of 15 mm. The animals were treated by oral gavage daily for 8 weeks before sacrifice. Results: Serum urea and creatinine, and overall physical tumor burden were significantly modulated in animals treated with variable doses of TAM compared to the untreated controls (n=5). Final body weight and tumor number were significantly different in the 10 mm-treated animals compared to those treated at 15 mm. There were no significant differences in histopathological features among all the groups. Conclusions: Our findings suggest the importance of standardizing tumour size and drug doses before initiation of treatment, particularly in the direct comparison of basic end-tumour physical parameters.

• Journal of Advanced Navigation Technology
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• v.10 no.1
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• pp.41-47
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• 2006

In this paper, a predistortion linearizer using the in-phase modulator is proposed. The harmonic generator of the proposed predistorter extracts a second harmonic signals. These signals are divided in-phase and quadrature-phase signals, and then amplifying each signals using variable gain amplifier. An in-phase modulator, modulate fundamental signal with second harmonic signals, generates the predistortion intermodulation distortion (IM) signals and controls amplitude and phase of them with modulation factors. As a result, this predistorter is suppressed intermodulation distortion signals of power amplifier effectively. The proposed linearizer has been implemented to operate in Cellular-band. The test results show that the third order IM is cancelled more than 20dB in case of CW 2-tone signals with ${\Delta}f$=1MHz. Also, it's improved the adjacent channel power ratio (ACPR) more than 7dB for IS-95 CDMA 1FA signals.