• Transactions of the KSME C: Technology and Education
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• v.2 no.2
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• pp.73-80
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• 2014

Drug delivery in human upper airway was studied by the numerical simulation of oral airflow. We created an anatomically accurate upper airway model from CT scan data by using a medical image processing software (Mimics). The upper airway was composed of oral cavity, pharynx, larynx, trachea, and second generations of branches. Thin sliced CT data and meticulous refinement of model surface under the ENT doctor's advice provided more sophisticated nasal cavity models. With this 3D upper airway models, numerical simulation was conducted by ANSYS/FLUENT. The steady inspiratory airflows in that model was solved numerically for the case of flow rate of 250 mL/s with drug-laden spray(Q= 20, 40, 60 mL/s). Optimal parameters for mechanical drug aerosol targeting of predetermined areas was to be computed, for a given representative upper airways. From numerical flow visualization results, as flow-rate of drug-laden spray increases, the drag spray residue in oral cavity was increased and the distribution of drug spray in trachea and branches became more homogeneous.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.8 no.3
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• pp.127-132
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• 1975

This is an experimental study that aimed to find out a possible relationships between the noise of the ship and the intelligent quotient, and the creativity of the crew member during June 5, to August 24, 1975. The experiment was carried out on the university training ship, the Oh-Bae-San Ho(1,126 tons), and the Kwan-Ak-San Ho (243 tons) and the training ship Baek-Kyung Ho (380 tons) of Je-ju College, where the total number of 144 students engaged on their tasks of practical exercise. And the following results were obtained : The decreases of I.Q. was evident as compared to the score obtained at the class room; soon after the embarking of the ship, the students on the deck decreased the score by $7\%$ of what they obtained at the class room while the students in the engine room decreased by $13\%$. The I.Q. was regaining the normal state after three days of embarking seemingly showing the fact that the students became adapted to the noise of the ship, but no remarkable improvement was visible during the period of 3 days to 35 days on the ship. One of the remarkable fact that had not been expected was that the problems for audio discernment was much easily solved in the midst of noise that made oral communication impossible (102 dB) than in the place of noise where conversation was possible(67 dB).

• The Journal of the Korea Contents Association
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• v.20 no.10
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• pp.25-34
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• 2020

Community question and answering service is one of the main sources of information and knowledge in the Web. The quality of information in question and answer documents is determined by the clarity of the question and the relevance of the answers, and the readability of a document is a key factor for evaluating the quality. This study is to measure the quality of documents used in community question and answering service. For this purpose, we compare the frequency of occurrence by vocabulary level used in community documents and measure the readability index of documents by institution of author. To measure the readability index, we used the Dale-Chall formula which is calculated by vocabulary level and sentence length. The results show that the vocabulary used in the answers is more difficult than in the questions and the sentence length is longer. The gap in readability between questions and answers is also found by writing institution. The results of this study can be used as basic data for improving online counseling services.

• The Journal of the Korea Contents Association
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• v.9 no.10
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• pp.258-267
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• 2009

This study purposed to develop GIS model for evaluating hospital location in a metropolitan city. Secondly, the suitability score of hospital was compared with the number of outpatient/inpatients of hospitals. This study used administrative data collected from the annual report of the 5 ward offices from Daejeon in Korea in 2004. 7 Acute care hospitals operated in Daejeon in 2004 were selected for the analysis. The suitability of hospitals in a metropolitan city was evaluated by the economic factors which were assumed to influence the health care demand. Each criterion was measured from each Dong. Correlation coefficients between the suitability score of hospital and the number of patients were varied depending on the buffering size. The relationship showed positive relationship with the number of inpatient (0.15) and outpatients (0.10) on the 0.5km buffering size. However, the correlation coefficients were changed to a negative direction or decreased when the buffering size was increased to 1.0km, 1.5km, and 2.0km.

• The KIPS Transactions:PartC
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• v.16C no.5
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• pp.589-596
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• 2009

Until now, some protocols have been presented to provide vehicle's anonymity and unlinkability in VANET by means of issuing multiple anonymous certificates to each vehicle from the trust authority, or shot-time anonymous certificate to a vehicle after mutual authentication between a Roadside Unit (RSU) and the vehicle. However, these protocols have high overheads of the trust authority, RSUs and vehicles for generating anonymous certificate. In this paper, we propose an efficient anonymous authentication protocol, in which RSUs can issue multiple shot-time anonymous certificates to a vehicle to alleviate system overheads for mutual authentication between vehicles and RSUs. Several simulations are conducted to verify the efficiency of the proposed protocol in terms of RSU valid serve ratio and vehicle's computational costs. Moreover, the proposed protocol provides unlinkability and traceability when multiple RSUs are compromised, whereas previous protocols do not provide unlinkability and traceability.

• Nuclear Engineering and Technology
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• v.24 no.1
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• pp.86-97
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• 1992

The purpose of this paper is to evaluate the direct vessel injection design from a pressurized thermal shock(PTS) viewpoint for the Combustion Engineering System 80+ A break of the main steam line from zero power and a 0.05 ft$^2$small break loss-of-coolant accident (LOCA) from full power were selected as the potential PTS events. In order to investigate the stratification effects in the reactor downcomer region, the fluid mixing analysis was performed using the COMMIX-IB code for steam line break and using the REMIX code for 0.05 ft$^2$small break LOCA. The stress distributions within the reactor vessel walls experiencing the pressure and the temperature transients were calculated using the OCA-P code for both events. The results of the analysis showed that a small break LOCA without decay heat presented the greatest challenge to the vessel, however, there is no crack initiation through end-of-life of the vessel with consideration of decay heat.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.12
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• pp.1166-1173
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• 2011

Electro-Mechanical Ignition Safety Device(EMISD) for solid rocket motor is designed and manufactured. The EMISD utilizes a true rotary solenoid for arming mechanism and an electric squib(initiator) for generating ignition energy. In order to prove the ignition capability of the EMISD, 10-cc Closed Bomb Test(CBT) is performed, which measures the pressure built by high temperature and high pressure gas generated by operating EMISD. The pressure built in the free volume of 10-cc closed bomb and the opening time of the ignition gas outlet are calculated using one dimensional gas dynamic model which is composed of the ideal gas equation and mass-energy conservation equation. Comparing the test result with model prediction, it is realized that the pressure built in the free volume of closed bomb due to the firing of EMISD, has the efficiency ratio of about 34%.

• Information Systems Review
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• v.7 no.1
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• pp.81-96
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• 2005

Because the web sites are in common today, the access to the web for disabled people and old aging people, what we call accessibility, becomes more important. Even though efforts to reduce the informational gap resulted from the lack of the accessibility have been carried out, the studies in this field in Korea are not still in popular. In this study, previous research on the measurements for the accessibility is reviewed and then a new model measuring accessibility is suggested. To increase the validity of the measurement, both an automated tool and a manual test are employed. First we used the 'A-Prompt', one of the popular automated validation tools and analyzed web sources, and applied manual tests by HPR Screen Reader. With the error rates calculated, the accessibility of the government web sites between Korea and the United States was compared and finally the conclusions were drawn.

• Journal of IKEEE
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• v.24 no.3
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• pp.821-827
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• 2020

In particular, vehicles with internal combustion engines of public transportation such as diesel and CNG buses are in urgent need of measures to reduce emissions as they have a long daily total mileage, long driving hours and a large number of vehicles. In this paper, the fuel consumption rate (km/kWh) was actually measured through road test of electric buses. Based on the measured values, CO₂ emissions from internal combustion engines and electric buses were calculated per bus. In addition to environmental improvement effects such as the expected reduction of carbon dioxide compared to CNG buses when replacing city buses with electric buses, additional effects were analyzed when the replacement of CNG buses is expanded to electric buses.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.1
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• pp.19-21
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• 2012

The engine oil life of internal combustion engine is shorted by the thermal effect and that causes air pollution. In order to measure the status of engine oil accurately, the exchange of new oil extends the life of combustion engine and reduces environmental pollution. Capacitance probes, such as engine oil and fluids can be used to measure the dielectric constant. In this paper, the degradation of engine oil varies depending on the degree of dielectric properties was analyzed. Depending on the state of the oil, the variant capacitance of the probe was measured by LCR Meter, respectively, and then the permittivity of oil was calculated. In addition, according to the size of the probe by measuring the change in capacitance measurement, accuracy of dielectric constant are presented. According to oil contaminated with the more increase in dielectric constant, we can decide that contaminated oil is available.