• Journal of Mechanical Science and Technology
• /
• v.15 no.5
• /
• pp.646-655
• /
• 2001

This paper reports the effects of nozzle exit boundary layer swirl on the instability modes of underexpanded supersonic jets emerging from plane rectangular nozzles. The effects of boundary layer swirl at the nozzle exit on thrust and mixing of supersonic rectangular jets are also considered. The previous study was performed with a 30°boundary layer swirl (S=0.41) in a plane rectangular nozzle exit. At this study, a 45°boundary layer swirl (S=1.0) is applied in a plane rectangular nozzle exit. A three-dimensional unsteady compressible Reynolds-Averaged Navier-Stokes code with Baldwin-Lomax and Chiens $\kappa$-$\xi$ two-equation turbulence models was used for numerical simulation. A shock adaptive grid system was applied to enhance shock resolution. The nozzle aspect ratio used in this study was 5.0, and the fully-expanded jet Mach number was 1.526. The \"flapping\" and \"pumping\" oscillations were observed in the jets small dimension at frequencies of about 3,900Hz and 7,800Hz, respectively. In the jets large dimension, \"spanwise\" oscillations at the same frequency as the small dimensions \"flapping\" oscillations were captured. As reported before with a 30°nozzle exit boundary layer swirl, the induction of 45°swirl to the nozzle exit boundary layer also strongly enhances jet mixing with the reduction of thrust by 10%.

• Journal of the Korea Computer Industry Society
• /
• v.5 no.4
• /
• pp.481-490
• /
• 2004

Today, most education activities in the junior or senior schools are connected with evaluation. In fact, the evaluation to be accomplished is not the practice of college or university entrance examination but the evaluation analysis of studies accomplishment. In this program, students process their teaming contents according to their level, and they evaluate the accomplishment of learning by themselves. Through the various analysis of evaluation, students who are not in the appropriate level get into the learning plan of low level course. This study makes them notice the lack of teaming ability in time and proposes proper evaluation system which offers right feedbacks and various analysis information for themselves.

• Journal of the Korea Safety Management & Science
• /
• v.17 no.1
• /
• pp.53-66
• /
• 2015

This study classified the study subjects as apartment residents and managers, and conducted the descriptive statistics of research questions related to the effectiveness of the lightweight partition walls and the evacuation space. This study also conducted T-test and Anova to find the different perceptions of the lightweight partition walls and the evacuation space, and the different perceptions of related laws according to the characteristics of the residents and managers. The findings and suggestions were as follows. Firstly, strengthening of the Senior Fire Safety Manager system to prevent the insolvency of fire safety management due to the affiliate. Secondly, implementing enhanced penalties in accordance with not implementing residents education, in order to prevent not smoothly delivering manager trained education to residents. Thirdly, adjusting hands-on training time according to the gender of the managers to supplement women's relatively low perceptions of lightweight partition. Fourthly, mandating evacuation guidance stickers on the evacuation space for residents to remove obstacles in the evacuation space. Finally, establishing regular residents education system in order to improve the awareness of the related laws for residents residing over 16th floors.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2003.11a
• /
• pp.422-431
• /
• 2003

Helicopter-borne electromagnetic (HEM) systems were originally developed for the exploration of mineral deposits. The frequency range of a conventional HEM system for mineral exploration, however, is relatively low and so not invariably suitable for its application to the fields of civil engineering because of its poor resolution in the shallower part of the earth. A DIGHEM HEM system was acquired by Nippon Engineering, with the frequencies chosen by the senior author. The five frequencies range from 220 Hz (the lowest) to 137,500 Hz (the highest). These frequencies improve the resolution of materials in the shallower part while maintaining a depth of investigation of greater than 100 m. This paper describes six case histories of geological and geotechnical surveys for civil engineering using HEM. These case histories include HEM surveys for investigating landslide, an alluvial area, root selection of road construction, areas related to dam and tunnel construction, and the simultaneous joint inversion of HEM and CSAMT data for a deep tunnel. These survey results show that HEM has sufficient resolution in both horizontal and vertical directins to contribute significantly to outlining the regional geology and its engineering problems.

• Proceedings of the KIEE Conference
• /
• 2007.04a
• /
• pp.436-438
• /
• 2007

As the sensors and communication technology get advance, the remote health diagnosis for patients and senior persons at home are possible now without visiting doctors in hospitals. A low-power ubiquitous health check device was developed adapting Real-Time Embedded Linux is developed. This ubiquitous device is consisted of three sensors. The wrist type health checking terminal acquires periodically the health data by using a blood pressure sensor, a pulse sensor and a body temperature sensor. It transmits the health data to the access point located at the home center through the ZigBee wireless communication modem. This health data collector or access point device sends the data again to the main server operated in a hospital or health care organization. The health server control continuously the input data and sends an alarm signal to the assigned. doctor and responsible persons using cellular SMS when any dangerous events occur. This wrist type health check device has an embedded linux OS using Intel PAX255 MPU. The developed U-Health system is applicable for checking patients health in remote at home. And their family or related persons in remote site can check the patients health status at any time. They can be assured by receiving SMS record and alarm of emergency case which is transmitted from the health server.

• Journal of Society of Preventive Korean Medicine
• /
• v.17 no.1
• /
• pp.65-76
• /
• 2013

Objectives : Aim of this study is to contribute to establishment of the Traditional Korean Medicine (TKM) policies in the future. Final assessment for 12 of the forecasting projects was carried out on the TKM policies that deduced by professionals in 1996 whether or not to realize in 2013. Methods : We investigated governmental and private research projects, reports and papers, and laws and systems on the forecasting projects. We reviewed them through the Traditional Korean Medicine Information Portal OASIS (http://oasis.kiom.re.kr), Korean studies Information Service System (KISS) (http://kiss.kstudy.com/) and DBpia (http://www.dbpia.co.kr/), Akomnews(http://www.akomnews.com/), THE MINJOK MEDICINE NEWS(http://www.mjmedi.com/), Ministry of Government Legislation(http://www.law.go.kr/). Results : Of the 12 forecasting projects, five were judged as 'realization', four were as 'partial realization' and three were as 'un-realization', The realization rate was 75.0%. Three un-realized projects included the TKM insurance coverage for various herbal medicines, leadership secure on medical technicians and commercialization of the TKM managing system on senior medicare policy. Realization of the future forecasting TKM policy projects was decided depending on conditions such as the importance, domestic capability levels, principal agents, methods and restrains. Conclusions : Continuous studies and new developed forecasting projects for the TKM policies will be required to realize the projects in the future.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.9 no.2
• /
• pp.544-549
• /
• 2008

National Education Information System (NEIS) is an ambitious reform project in the field of education, which is launched mainly by government initiative and is to link administrational work of between schools and their senior administration offices via internet. NEIS is introduced to lighten the teachers' overburden, to standardize the work process and to bring better quality education to each classroom and make it possible for those involved in education to resolve any related educational problem on line. This paper aims to construct a hierarchy model consisting of key factors such as administrative and technological factors for the effective use of NEIS and to evaluate the relative importance among key factors using multiple decision-making technique. Eventually, the analysis results can be utilized to develop the future improvement strategy of NEIS and to satisfy the users.

• Journal of Engineering Education Research
• /
• v.23 no.2
• /
• pp.14-23
• /
• 2020

Based on the constructivist learning environments model and the learner-centered psychological principles, STEAM education program with the theme of eliminating smog was developed. Through the program, senior elementary school students will learn and apply the convergence knowledge of science, technology, engineering, arts and mathematics such as the human body's respiratory system (S), immune system (S), big data (M, T), computer programming(M), and aduino sensor utilization (E) directly to solve the problem. After expert validity testing, we found that developed program meet the standards of STEAM education program development and can develop creative thinking skills to find and solve problems in students' daily lives. In addition, this study is meaningful in providing a reference example for the development of STEAM education programs that enhance convergence knowledge in the future.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2007.06a
• /
• pp.285-290
• /
• 2007

Electrical and electromagnetic methods were widely applied to survey of civil engineering, environment site assessments and maintenance of underground structures in Korea. Electro-physical properties measurements of soil and rock are necessary in order to quantitatively estimate the ground from these survey results. A few geotechnical researcher groups have been simplified measurement system of the electro-physical properties, which was intermittently operating by the necessity. Recent strong concern about $CO_2$ underground storage and development of gas hydrate projects have urged many advanced countries. The electro-physical properties estimation of the deep object stratum is very importance for basic information of these research. So, advanced countries have a high-end measurement system with high temperature(200 degrees) and pressure(300 MPa), also they have been a lot of experience and know-how on the electro-physical properties measurement.

• Management & Information Systems Review
• /
• v.4
• /
• pp.309-325
• /
• 2000

Organizations rely on Secure ID resources today to handle vast amounts of information. Because the data can vary widely in type and in degree of sensitivity, employees need to be able to exercise flexibility in handling and protecting it. It would not be practical or cost-effective to require that all data be handled in the same manner or be subject to the same protection requirements. Without some degree of standardization, however inconsistencies can develop at introduce risks. Policy formulation is an important step toward standardization of security activities for ID resources. ID security policy is generally formulated from the input of many members of an organization, including security officials, line managers, and ID resource specialists. However, policy is ultimately approved and issued by the organization's senior management. In environments where employees feel inundated with policies, directives, guidelines and procedures, an ID security policy should be introduced in a manner that ensures that management's unqualified support is clear. The organization's policy is management's vehicle for emphasizing the commitment to ID security and making clear the expectations for employee involvement and accountability. This paper will discuss ID security Policy in terms of the different types (program-level and issue-specific), components, and Implementation of Expert System Simulation based on 4GL, PowerBuilder.