• 한국항공운항학회지
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• 제23권1호
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• pp.67-73
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• 2015

The previous limited authority system capable of implementing attitude command response type and translational command response type by operating SAS actuator has the problem of early saturation of SAS actuator since SAS actuator should compensate the mechanical linkage displacement caused by control sick movement. In this paper, a limited authority system where flight control computer receives the command from the control stick which is not connected to the mechanical linkage is described. In this system the compensation by the SAS actuator is not necessary and SAS actuator saturate later. SAS actuator saturation problem can be further relaxed by using the trim actuator. This new limited authority system is applied to BO-105 model, simulation is performed for the doublet input and pirouette maneuver is also simulated and analyzed.

• 한국항공운항학회지
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• 제21권4호
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• pp.34-40
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• 2013

Attitude command response type required for enhanced handling qualities of helicopter can be implemented by mechanical automatic flight control system with SAS actuators which have limited authorities. However, the early saturation of SAS actuator hinders the helicopter from following the attitude command for large stick command. Auto-trim controller can delay SAS actuator's saturation by utilizing trim actuators and allows the attitude command response type for larger stick command. This paper describes the control law for limited authority system of helicopter with auto-trim. Limited authority system is applied to BO-105 linear dynamic model and simulation is performed along with handling quality analysis.

• 한국환경과학회지
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• 제23권9호
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• pp.1655-1662
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• 2014

A comprehensive fractionation technique was applied to a set of water samples obtained along drinking water treatment process with ozonation and biological activated carbon (BAC) process to obtain detailed profiles of dissolved organic matter (DOM) and to evaluate the haloacetic acid (HAA) formation potentials of these DOM fractions. The results indicated that coagulation-sedimentation-sand filtration treatment showed limited ability to remove hydrophilic fraction (28%), while removal of hydrophobic and transphilic fraction were 57% and 40%, respectively. And ozonation and BAC treatment showed limited ability to remove hydrophobic fractions (6%), while removal of hydrophilic and transphilic fractions were 25% and 18%. The haloacetic acid formation potential (HAAFP)/dissolved organic carbon (DOC) of hydrophilic fraction was the highest along the treatment train and HAAFP/DOC of hydrophilic fraction was higher than hydrophobic and transphilic fraction as 23%~30%, because of better removal for hydrophobic fraction both in concentration and reactivity.

• 한국정보기술학회 영문논문지
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• 제8권2호
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• pp.111-118
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• 2018

Information communication authority module software contains various functions and services. A software test is the only acceptance test step. Recently, however, all development steps have become important. In particular, the software acceptance step is very high, and a study of the effective use of limited time and resources on acceptance step is needed. This study examined the efficiency of the Test Design Technique for Software Test. The proposed Test Design process was applied to the domain systems of info-communication and the degree of improvement was measured. This paper establishes Software Test design process Infrastructure based on the developed software.

• 한국임상수의학회지
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• 제35권3호
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• pp.107-110
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• 2018

A 5-year-old Thoroughbred race horse was presented to Busan Korea Racing Authority equine hospital with a 3-year history of a slow-growing left rostral maxillary mass. The location and progressive growth of the mass eventually resulted in poor food prehension, quidding and mouth bit placement. The mass was solitary and hard, and covered by normal smooth oral mucosa. Radiographic examination of the maxillae showed a flocculated and mixed radiolucent lesion protruding outward and displacing the 202 and 203 teeth caudally. The 202 tooth was in normal size and the 203 tooth was hypoplastic on radiography. Under general anesthesia, a partial surgical resection of the mass was performed to minimize functional loss and facilitate prompt return to track. After surgery, there was improvement in food intake, mouth bit placement, and cosmetic appearance. Histopathological examination determined the resected maxillay mass to be an ossifying fibroma. However, there was continued growth of remnant mass in the maxilla. Equine ossifying fibroma is a rare condition and primarily affects the rostral mandible, and less commonly, the maxillae. In this case, the lesion was slow-growing, and caused cosmetic and functional impairments, including poor food intake and reduced trainability. Surgical resection was performed, but the effect of treatment was limited due to advanced size / stage of the tumor. Early dental care is suggested for horse owners to prevent belated identification and improve successful treatment of oral disorders like ossifying fibroma.

• Safety and Health at Work
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• 제13권2호
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• pp.141-147
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• 2022

Background: On the basis of its role for the development of occupational health research, information, good practices, the International Commission on Occupational Health (ICOH) launched the present survey to collect information on public health and prevention policies put in place by the governments of the countries in the world to contain the pandemic. Methods: A cross-sectional study was conducted through an online questionnaire focused on COVID-19 data, public health policies, prevention measures, support measures for economy, work, and education, personal protective equipment, intensive care units, contact tracing, return to work, and the role of ICOH against COVID-19. The questionnaire was administered to 113 ICOH National Secretaries and senior OSH experts. Collected data refer to the period ranging from the beginning of the pandemic in each country to June 30, 2020. Results: A total of 73 questionnaires from 73 countries around the world were considered valid, with a 64.6% response rate. Most of the respondents (71.2%) reported that the state of emergency was declared in their country, and 86.1% reported lockdown measures. Most of the respondents (66.7%) affirmed that the use of face masks was compulsory in their country. As for containment measures, 97.2% indicated that mass gatherings (meetings) were limited. Regarding workplace closing, the most affected sector was entertainment (90.1%). Conclusion: The results of this survey are useful to gain a global view on COVID-19 policy responses at country level.

• 한국환경과학회지
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• 제24권12호
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• pp.1551-1558
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• 2015

In Korea, many drinking water treatment plants (DWTPs) have introduced and are going to introduce biological activated carbon (BAC) process to treated dissolved organic matter (DOM) in water which are difficult to control by conventional water treatment processes. Even though more decade have passed since introduced BAC in Korea, most of BAC operating method was followed to the modified sand filter operating manuals. In case of BAC backwashing, many DWTPs set the periods of backwashing about 3~5 days. In this study, we have collected data to set the proper BAC backwashing periods from both pilot-plant and real DWTPs. We had measured heterotrophic plate count (HPC), turbidity, water temperature, dissolved organic carbon (DOC) and headloss from just after backwashing to the next backwashing time for two years. Considering water quality factors, the BAC run time from backwashing to the next backwashing could extend more 30 days without water quality deterioration if the head loss do not reach the limited level which depends on each BAC facilities' condition. It means the BAC treated water could be saved in the proportion of extended the backwashing period to the existing backwashing period.

• 한국응용과학기술학회지
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• 제30권4호
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• pp.688-700
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• 2013

하수 슬러지로부터 추출된 유지를 이용하여 바이오디젤 생산에 대해 고찰하였다. 바이오디젤 생산의 밝은 전망에도 불구하고, 이를 상용화하기 위한 노력은 매우 제한되어 있다. 주요 장애물 중 하나는 전체 생산비용의 약 70~75%를 구성하는 정제 유지의 공급 원료와 연관된 높은 가격이다. 따라서 이를 극복하기 위하여 폐유나 낮은 품질 유지 등의 저가 원료를 사용하여 바이오디젤의 생산 비용을 낮추는 기술이 제안되어 왔다. 이런 측면에서 하수 슬러지로부터 추출된 유지는 비교적 저렴하여 유망한 원료로 평가받고 있다. 본 연구에서는 하수 슬러지로부터 추출된 유지를 이용한 바이오디젤의 생산기술을 검토하였다. 하수 슬러지로부터 유지 추출공정 및 에스테르화 전환공정 및 무촉매 열화학 전환공정을 살펴보았다.

• Tribology and Lubricants
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• 제33권6호
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• pp.263-268
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• 2017

The significance of maintaining the soil environment is gradually increasing owing to soil and underground water contamination by petroleum leak accidents. However, the purification of soil is an expensive and more time-consuming process than the purification of contaminated water and air. Moreover, determining the source and people responsible for soil pollution gets often embroiled in legal conflicts, further delaying the cleanup process of the contaminate site. Generally, TPH (total petroleum hydrocarbon) pattern analysis is used to determine the petroleum species and polluter responsible for soil contamination. However, this process has limited application for petroleum products with a similar TPH pattern. In this study, we analyze the TPH pattern and specific sectional ratio (${\sim}C_{10}$, $C_{10}-C_{12}$, $C_{12}-C_{36}$, and $C_{36}{\sim}$) of various domestic petroleum products to identify the petroleum product responsible for soil contamination. Also, we perform BTEX (benzene, toluene, ethyl benzene, xylene) quantitative analysis and determine B:T:E:X ratio using GC-MS. The results show that gasoline grade 1 and 2 have a similar TPH pattern but different BTEX values and ratios. This means that BTEX analysis can be used as a new method to purify soil pollution. This complementary TPH and BTEX method proposed in this study can be used to identify the petroleum species and polluters present in the contaminated soil.

• 한국수소및신에너지학회논문집
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• 제29권3호
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• pp.299-305
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• 2018

The domestic label fuel economy measurement method is the same as the North American measurement method. The results of two test modes (city [FTP-75 mode], highway [HWFET mode]) are calculated to be equivalent to the final fuel economy value calculated as the result of five test modes reflecting various environmental conditions and driving patterns 5-cycle correction formula is used. In this study, we tried to find out that the difference between the domestic label fuel economy of the vehicle and the real road fuel economy felt by the driver compared to the new vehicle condition as the mileage increases. Using domestic label fuel economy measurement method, Four gasoline vehicles and four diesel vehicles were tested for the fuel economy of a new vehicle with a mileage of 150 km or less and domestic fuel economy test $6,500{\pm}1,000km$ durability condition and 15,000 km durability. It is confirmed that the certain portion (6,500 km endurance vehicle) The increase in mileage did not affect the fuel economy or the emission gas significantly, indicating that vehicle durability was limited.