• Architectural research
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• 제1권1호
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• pp.47-53
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• 1999

An interesting of desktop air-conditioning system is the Personal Environmental Module(PEM) System. The PEM system allows the occupant to choose the desired temperature, air volume and direction of the discharged air. In this study, the measurements on the age of air and the air change effectiveness, using the tracer gas method, are carried out to analyze the ventilation performance for provision of fresh air near the breathing zone by the PEM. The relations between the PEM for optimal control and other factors related to indoor air quality, and the ventilation for the PEM are examined. Also, three different supply diffuser types(desktop, floor and ceiling) are compared in view of their ability to distribute supply air to the workstation breathing zone. The desktop diffuser type could deliver air directly to the occupants breathing zone with a high degree of effectiveness. The minimum local age of air was measured in the breathing zone, which is directly supplied with air from the PEM diffusers, and the measured local air change effectiveness of the desktop diffuser in the breathing zone was about 1.13 to 1.23 times greater than that of the ceiling and floor diffusers. When the minimum outside air change rate as specified using ASHRAE Standard 62R is supplied with a desktop diffuser type, the volume of outside air can be reduced 13 to 23%, resulting in a commensurate in ventilation energy use.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.790-793
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• 2005

In these days, the piezoresistive material has been applied to various sensors in order to measure the change of physical quantities. But the relationship between the sensitivity of a sensor and the position and size of piezoresistor has rarely been studied. Therefore, this paper was focused on the effect of residual stress induced in piezoresistor on the distribution of resistance change ratio and supposed the feasible position of piezoresistor. The resulting are following; The tensile residual stress in the vicinity of piezoresistor decreased the value of resistance change ratio and could not effect on all the area of diaphragm but local area around the piezoresistor. Also, the piezoresistor in the diaphragm type pressure sensor with boss should fabricate in the edge of boss in order to increase the sensitivity of pressure sensor.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.50-56
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• 2022

Change Orders generally impact cost and schedule performance of highway projects. However, highway projects that do not have any change orders also face cost growth and schedule delays. This study seeks to determine the cost and schedule performance of Texas DOT projects by collecting project data for 120 highway projects completed between 2016 to 2020. For the study, we selected project data that has zero or negative change orders which were then grouped and analyzed based on their Project Types i.e., maintenance works; structural works; restoration and rehabilitation works; and safety works. The study found that performance of Maintenance and Safety type projects had less cost and schedule growth among the data analyzed. Statistical tests also found that even though the projects have no change orders, Rehabilitation and Restoration type projects experienced significant schedule growth compared to others. However, the data did not show any significant cost and schedule growth for the projects when statistical tests were performed on overall data. The study concluded that highway projects are experiencing schedule growth even though the projects had no change orders. Results from the study can help planners, engineers, and administrators to gain better insight on how different types of highway projects are performing in terms of cost and schedule and eventually derive appropriate solutions to minimize cost and schedule growth in such projects.

• 한국콘텐츠학회논문지
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• 제19권12호
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• pp.215-228
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• 2019

본 연구는 혁신형 중소기업을 연구대상으로 하여, CEO의 유형에 따른 기술혁신역량이 기술혁신성과에 미치는 영향을 미시적으로 분석하였다. 또한, 혁신형 중소기업특성에 따라 CEO유형이 기술혁신역량에 미치는 영향, 기술혁신역량이 기술혁신 성과에 미치는 영향을 함께 연구하였다. 연구목적을 달성하기 위해, 중기부에 등록된 혁신형 중소기업 250사(社)를 연구대상으로 하여 실증분석을 실시하였으며, 연구결과는 다음과 같다. 첫째, CEO 유형이 기술혁신역량에 미치는 영향 분석 결과, 시장중심형 CEO, 기술형 CEO, 컨설턴트형 CEO는 기술변화 감지역량에 유의한 영향을 미치는 것으로 나타났으나, 관리형 CEO는 기술변화감지역량에서 통계적으로 유의한 차이가 나타나지 않았다. 또한, 혁신형 중소기업의 CEO유형은 기술혁신역량의 R&D기술 소화역량에는 영향을 미치지 않는 것으로 분석되었다. 둘째, 기술혁신역량과 기술혁신성과 간의 관계를 분석한 결과 통계적으로 유의한 영향을 미치지 않았다. 셋째, 중소기업 성장단계에 따른 CEO유형과 기술혁신역량 간 조절효과를 분석한 결과 기술형 CEO와 컨설턴트형 CEO는 기술변화감지역량에 영향을 미치는 것으로 분석 되었으나, 관리형 CEO와 시장형 CEO는 조절효과가 발생하지 않았다. 넷째, 혁신형 중소기업 성장단계에 따른 기술혁신역량과 기술혁신성과 간 조절효과를 분석한 결과 통계적으로 유의한 영향을 미치지 않았다.

• Restorative Dentistry and Endodontics
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• 제20권2호
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• pp.758-767
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• 1995

The purpose of this study was to evaluate canal shaping ability after canal preparation by using engine-driven nickel-titanium file and endosonic file in curved canals. 30 mesiobuccal canals of molars extracted within recent 3 months were divided into 3 groups. Group I and group II were prepared by using engine-driven nickel-titanium Gates-Glidden drill type and the engine-driven nickel-titanium file type. Group III prepared by using en do sonic file. The image of preinstrumented canals was taken by X-ray. The image of postinstrumented canal was taken by X-ray in the same condition of preinstrumentation. A magnified X-ray image on magnifier screen was traced and then compared the preinstrumentated canal image with the postinstrumentated canal image by superimposing method. The following results were obtained : 1. In the change of canal curvature, the engine-driven nickel-titanium Gates-Glidden drill type showed the least change and the ultrasonically filing showed the greatest change. 2. In the percentage of canal enlargement, the engine-driven nickel-titanium file type was greatest at all level(p<0.05), the apex of all group was the greatest, the difference of ultrasonically filing group showed greater between apex and cervix. 3. The percentage of canal enlargement on convex side was greater than that of on concave side in apex of each group(p<0.05). In the ultrasonically filing group, both sides of canal enlargement showed sharply difference(p<0.01). 4. The percentage of canal enlargement on convex side was greater than that of on concave side in the third of cervix of the engine-driven nickel-titanium file type and the ultrasonically filling. The percentage of canal enlargement of convex and concave side in the third of middle of the engine-driven nickel-titanium Gates-Glidden drill type show a similar canal enlargement between convex side and concave side. As above result, the engine-driven nickel-titanium file type was greater in canal enlargement than the other instruments. The engine-driven nickel-titanium Gates-Glidden dirll type was efficient endodontic instrument for curved canal preparation because it was least change in canal curvature.

• 한국농공학회지
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• 제37권5호
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• pp.90-100
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• 1995

This study was performed to develop the lightweight concrete using synthetic lightweight aggregate and natural coarse aggregate. Mixing ratios were three types, the first type was mixed cement and synthetic lightweight fine aggregate (Type CP), the second type was mixed cement, synthetic lightweight fine aggregate and synthetic lightweight coarse aggregate (Type CPE), the third type was mixed cement, synthetic lightweight fine aggregate and natural coarse aggregate (Type CPN). The results of this study are summarized as follows ; 1. The W/C of each mixing ratio was increased with increase of the amount of cement used, and it was shown higher in order of Type CP, CPN, CPE. 2. The unit weight of Type CP, CPE and CPN was 1.473~1.647g/cm$^3$, 1.467~1.622g/cm$^3$ and 1.658~1 .838g/cm$^3$, respectively. And the absorption ratio was approximately 20%, which was higher than that of the normal cement concrete. 3. The compressive strength of Type CP was shown 178 ~249kg/cm2, Type CPE was shown 149~241kg/cm$^2$ and Type CPN was shown 196~297kg/cm$^2$, respectively. Each strength ratio was smaller than that of the normal cement concrete. 4. The pulse velocity of Type CP, CPE and CPN was 2, 688~3, 240m/sec, 2, 981~3, 324m/sec and 2, 989 ~ 3, 545m/sec, respectively. And it was increased with increase of strength and unit weight. 5. The length change ratio at 28 days was in the range of 0.057~0.077%, and earlier length change ratio was higher than that of the later.

• 한국정보시스템학회지:정보시스템연구
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• 제20권4호
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• pp.49-72
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• 2011

Business Process Change(BPC) is regarded as a salient factor to improve an organizations' efficiency in the current fast-changing business environment. Despite the tremendous popularity and great potential, the field of BPC adoption is littered with remarkable failures. Consequently, there have been many studies that have tried to identify the environmental factors that lead to successful BPC. However, most of them have not considered the effect of the interaction between the environmental factors on BPC success. According to Klempa(1995), the fit between environmental factors of a company may have the impact on its BPC success. Under this background, this paper empirically examines the effects of the fit between the type of BPC and the organization's culture on the success of BPC. Organization's cultures, organizational learning, as well as knowledge sharing are the dominant causes that have impact on the innovation characters of organization. Whether an organization has safety-oriented homogeneous culture or it has the change-oriented heterogeneous culture may have impact on its implementation of BPC. Also the implementation of BPC may be affected by whether the organization adopts the improvement project which accompanies only small changes or it adopts the innovation project which leads to critical changes. Thus, we analyzed the effect of the fit between the organization's culture and its BPC type on BPC success by using the survey data collected from the companies that have adopted BPC. The findings presented in this paper show that the organization having heterogeneous culture practicing innovation project and the organization having homogeneous culture practicing the improvement project resulted in the excellent BPC success.

• 한국표면공학회지
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• 제46권6호
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• pp.283-289
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• 2013

The experimental study for the temperature uniformity on the wafer using liquid-vapor phase heat transfer mechanism is performed. For the experiment, the heater plate which is consist of stainless steel container, working fluid and electrical heater is designed, manufactured and tested at the range of 600 to $850^{\circ}C$. The results showed that the phase change type heater plate was much more uniform and stable temperature on the heater plate surface and wafer than the uniform heat flux type heater plate at the atmospheric condition. Also, the results of 300 mm outer diameter of heater plate showed that the same temperature uniformity compared with 230 mm.

• 한국철도학회논문집
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• 제5권1호
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• pp.48-54
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• 2002

This research estimated decreased vibration level as quantitative according to change of track system on Seoul Subway Line No. 1 from existing ballasted track system(Pandrol type clip) to concrete track system(Youbgdan type isolation rubber clip). Following change to concrete system, vibration level at tunnel floor decreased between 4-8dB(V). Vibration equations suggested in this paper consider the velocity of train and can estimate quantitative vibration response. These are divided by ultimate limit state($\beta$=0), serviceability limit state($\beta$=1.28) and safety state($\beta$=3), respectively. The reliability index, $\beta$=0, means 50％ data line obtained by least squares best-fit line. The reliability index $\beta$=1.28 and 3 represent boundaries below 90％ and 99.9％ respectively.

• 시큐리티연구
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• 제7호
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• pp.155-189
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• 2004

The mission of the police as described by law is to guard the life, body and property of all citizens. Such duties should be accurately performed based on legal and democratic procedures because the works of the police are directively influencing the overall lives of the citizens by restricting their freedom. We are frequently watching the traffic police on the street or road. Traffic policing aims to reduce crime and the opportunities for criminal activity in relation to the use of roads, that is to improve road user behavior in order to reduce accidents. The characteristics of traffic accident change is not similar in each traffic condition. The purpose of this study is to analysis a type characteristics of traffic accident change, such as number of deaths and wounded persons by the time, the vehicle, the type the road, the age group. Based on the characteristics of traffic accident change, traffic accident countermeasures are proposed, in which some variable of traffic policies such as traffic facilities, traffic regulation, and traffic safety education.