• Journal of Korean Society of Transportation
• /
• v.17 no.1
• /
• pp.173-185
• /
• 1999

The purpose of this study is to develope a forecasting model to implement short-term Congestion Management Program (CMP) based on TDM strategies in Seoul. The CMP is composed of three elements: 1) setting a goal of short-term traffic management. 2) developing a model to forecast the impacts of TDM alternatives, and 3) finding TDM measures to achieve the goal To Predict the impacts of TDM alternatives, a model called SECOMM (SEoul COngestion Management Model) is developed. The model assumes that trip generation and distribution are not changing in a short term, and that only mode split and traffic assignment are affected by TDM. The model includes the parameter values calibrated by a discrete mode choice model, and roadway and transit networks with 1,020 zones. As a TDM measure implement, it affects mode choice behavior first and then the speeds of roadway network. The chanced speed again affects the mode choice behavior and the roadway speeds. These steps continue until the network is equilibrated. The study recommends that CMP be introduced in Seoul, and that road way conditions be monitored regularly to secure the prediction accuracy of SECOMM. Also, TDM should be the major Policy tools in removing short-term congestion problems in a big city.

• Journal of The Korean Association For Science Education
• /
• v.31 no.1
• /
• pp.14-31
• /
• 2011

This study investigated pre-service science teachers' motivation for career choice and their self-image as a science teacher. Although their motivations for becoming science teachers were very personal, three major characteristics emerged. First, during the process of their growth, their interest in education and science existed separately, and later the two interest were naturally focused on the job of a science teacher. When they find out that teaching science is right for them, they developed their inner motivation. Second, teaching opportunities to teach science subjects, including classroom observations, TA, tutor, and teacher-aid, played an essential role for them in finding their aptitude for science teaching. Third, their teaching-related experiences were very effective in building up their self-image as a science teacher and in preparing for the job. It also reinforced their inner motivation, which was important in finding their direction in life as a science teacher. Fourth, there were two categories for the self-image as a science teacher. One was teaching-oriented and the other was science subject-oriented. These images for the science teacher were closely connected with their inner motivation for science teaching.

• Nuclear Engineering and Technology
• /
• v.39 no.1
• /
• pp.31-42
• /
• 2007

Energy supply is increasingly showing up as a major issue for electricity supply, transportation, settlement, and process heat industrial supply including hydrogen production. Nuclear power is part of the solution. For electricity supply, as exemplified in Finland and France, the EPR brings an immediate answer; HTR could bring another solution in some specific cases. For other supply, mostly heat, the HTR brings a solution inaccessible to conventional nuclear power plants for very high or even high temperature. As fossil fuels costs increase and efforts to avoid generation of Greenhouse gases are implemented, a market for nuclear generated process heat will be developed. Following active developments in the 80's, HTR have been put on the back burner up to 5 years ago. Light water reactors are widely dominating the nuclear production field today. However, interest in the HTR technology was renewed in the past few years. Several commercial projects are actively promoted, most of them aiming at electricity production. ANTARES is today AREVA's response to the cogeneration market. It distinguishes itself from other concepts with its indirect cycle design powering a combined cycle power plant. Several reasons support this design choice, one of the most important of which is the design flexibility to adapt readily to combined heat and power applications. From the start, AREVA made the choice of such flexibility with the belief that the HTR market is not so much in competition with LWR in the sole electricity market but in the specific added value market of cogeneration and process heat. In view of the volatility of the costs of fossil fuels, AREVA's choice brings to the large industrial heat applications the fuel cost predictability of nuclear fuel with the efficiency of a high temperature heat source tree of Greenhouse gases emissions. The ANTARES module produces 600 MWth which can be split into the required process heat, the remaining power drives an adapted prorated electric plant. Depending on the process heat temperature and power needs, up to 80% of the nuclear heat is converted into useful power. An important feature of the design is the standardization of the heat source, as independent as possible of the process heat application. This should expedite licensing. The essential conditions for success include: ${\bullet}$ Timely adapted licensing process and regulations, codes and standards for such application and design ${\bullet}$ An industry oriented R&D program to meet the technological challenges making the best use of the international collaboration. Gen IV could be the vector ${\bullet}$ Identification of an end user(or a consortium of) willing to fund a FOAK

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.21 no.6
• /
• pp.146-164
• /
• 2022

Recently, the Korean government promoted the construction of metropolitan express subway to connect major transportation hub in the metropolitan area within 30 minutes. Most stations of the metropolitan express subway are connected to existing subway stations, so the importance of transfer increased. Although many studies have been conducted on the effect of transfer penalty on route choice, there are few studies on the transfer behavior of the metropolitan express subway. Therefore, in this study, a transfer behavior analysis was conducted on the Shinbundang Line, a representative metropolitan express subway. To analyze the transfer behavior according to the degree of traffic congestion and the presence of fare payment, route choice models were made using transport card data divided according to week, time, and user characteristics. As a result of the analysis, users of the metropolitan express subway had greater disutility to the transfer waiting time compared to the transfer moving time. Furthermore, especially during the peak time, EIVM(Equivalent in-vehicle minutes) of the transfer waiting time was 3.51. In this study, EIVM for metropolitan express subway users were analyzed to be 2.6 minutes, which is significantly lower than the results of previous studies on subways. This suggests that there is a difference in the transfer penalty between subways and metropolitan express subway, and that it is necessary to apply the transfer penalty between subways and express subway differently when forecasting subway traffic demand.

• Journal of Astronomy and Space Sciences
• /
• v.21 no.4
• /
• pp.329-342
• /
• 2004

In this paper, we present preliminary feasibility studies on three types of solar observation payloads for future Korean Science and Technology Satellite (STSAT) programs. The three candidates are (1) an UV imaging telescope, (2) an UV spectrograph, and (3) an X-ray spectrometer. In the case of UV imaging telescope, the most important constraint seems to be the control stability of a satellite in order to obtain a reasonably good spatial resolution. Considering that the current pointing stability estimated from the data of the Far ultraviolet Imaging Spectrograph (FIMS) onboard the Korean STSAT-1, is around 1 arc minutes/sec, we think that it is hard to obtain a spatial resolution sufficient for scientific research by such an UV Imaging Telescope. For solar imaging missions, we realize that an image stabilization system, which is composed of a small guide telescope with limb sensor and a servo controller of secondary mirror, is quite essential for a very good pointing stability of about 0.1 arcsec. An UV spectrograph covering the solar full disk seems to be a good choice in that there is no risk due to poor pointing stability as well as that it can provide us with valuable UV spectral irradiance data valuable for studying their effects on the Earth's atmosphere and satellites. The heritage of the FIMS can be a great advantage of developing the UV spectrograph. Its main disadvantage is that two major missions are in operation or scheduled. Our preliminary investigations show that an X-ray spectrometer for the full disk Sun seems to be the best choice among the three candidates. The reasons are : (1) high temporal and spectral X-ray data are very essential for studying the acceleration process of energetic particles associated with solar flares, (2) we have a good heritage of X-ray detectors including a rocket-borne X-ray detector, (3) in the case of developing countries such as India and Czech, solar X-ray spectrometers were selected as their early stage satellite missions due to their poor pointing stabilities, and (4) there is no planned major mission after currently operating Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) mission. Finally, we present a preliminary design of a solar X-ray spectrometer covering soft X-ray (2 keV) to gamma ray (10 MeV).

• Journal of Yeungnam Medical Science
• /
• v.6 no.2
• /
• pp.91-101
• /
• 1989

The goal of therapy in patients with traumatic carotid-cavernous fistulas is to occlude the fistula, preferably while maintaining the carotid blood flow. Since the introduction of the concepts of detachable balloon technique to occlude arteriovenous fistulas, the technique has become the treatment of choice in the management of traumatic carotid-cavernous fistulas. The major symptoms of traumatic CCFs are (1)pulsating exophthalmos, (2)orbital and cephalic bruit and murmur, (3) headache, (4) chemosis. (5) extraocular palsies, and (6) visual failure. Traumatic CCFs are combined with multiple associated lesions. We tried the occlusion of fistulas using Goldvalve balloons in 8 consecutive cases of traumatic CCF and the result of our experience is reported. Transarterial approach with manually-tied latex balloons is tried in all cases and the fistulas was successfully occluded in all cases. In 5 cases. the internal carotid artery was preserved and the arterial lumen was occluded along with fistula opening in :3 cases. In one case, surgical ligation was done because of symptoms recurred and incomplete occlusion of fistula. We experienced hemiparesis as a major complication in one case during occlusion tolerance test, which was remitted spontaneously. The results of Debrun balloon treatment were relatively excellent. We consider that the first choice of treatment of traumatic CCF is occlusion of the fistula by a detachable balloons.

• Journal of Environmental Science International
• /
• v.8 no.1
• /
• pp.83-94
• /
• 1999

A Study on the choice of proper region for moving cage culture facilities were carried out in the South Sea of Korea. Optimum temperatures of habitats for cage culture fishes, Sebastes schlegeli, Paralichthys olivaceus, Seriola quinqueradiata, Lateolabrax japonicus, Pagrus major, Takifugu vermicularis, and Mugil cephalus were 18~26$^{\circ}C$, 10~$25^{\circ}C$, 15~29$^{\circ}C$, 15~29$^{\circ}C$, 15~3$0^{\circ}C$, 15~$25^{\circ}C$, and 19~27$^{\circ}C$, respectively. In winter, wintering regions for continuous growth of fishes were proper around Komundo, Sorido, Soimal, Gadukdo and Chejudo for Paralichthys olivaceus and Lateolabrax japonicus, while Seoguipo and Udo for Seriola quinqueradiata, Pagrus major and Takifugu vermicularis. Sanji was not proper for wintering region because variation of water temperature is large by effect of strong northwestern wind. Wintering regions of Sebastes schlegeli and Mugil cephalus were not in the south of Korea. In summer, proper regions for fishes to avoid from damage by red tide were Komundo and around Chejudo. No red tide has occurred in these regions for 6 years. Mokpo and Yoja Bay were not proper for moving region because the former had strong tides and the latter had only one exit out of the bay which made it impossible to move cages in other route when dangerous red tides burst into.

• Journal of Gifted/Talented Education
• /
• v.21 no.3
• /
• pp.631-658
• /
• 2011

The impact of the academic achievements of science high school graduates during the science high school period on their creative productivity, higher education, occupation, and income were investigated with 244 science high school graduates who belonged either to top 30% or bottom 30% in terms of their high school GPA. The factors contributed to the choice of current occupations and life were also investigated through retrospective approach. Survey questionnaire was administered to 244 adults who graduated from 18 science high schools before 2001. Thirteen graduates who completed questionnaire were interviewed face-to-face. Their ages ranged from 28.00 to 42.84. The high achievers were belonged to top 30% and the low achievers were belonged to the bottom 30% and the two groups demonstrated significant differences in their higher education and creative productivity. More doctoral degree holders and more number of creative products were found in the high achievers than the low achievers. 58.1% of the high achievers and 42.7% of the low achievers were working as professional scientists. Significantly more high achievers were working on tasks which require creative problem solving abilities and their income was significantly higher than the low achievers. For both groups, parents were the most significant individuals and then teachers were the second most important persons who impacted to their life and the choice of their occupation. Interviews with 13 graduates confirmed the survey results especially in their choice of life style and occupation. They were also influenced the most by parents, then teachers, and their friends who were more interacting with the socioeconomic environment when they selected university, major, and occupation. The results implies that high school achievement has significant influence on their future achievement to some extent and schools need to provide guide on the career choice not only to the students but also to their parents, since students' career choices are much influenced by their parents.

• Korean Journal of Head & Neck Oncology
• /
• v.17 no.2
• /
• pp.190-193
• /
• 2001

Background and Objectives: Reliable and versatile free flap has become a mainstay in reconstruction of the head and neck. But until now pectoralis major myocutaneous flap (PMMCF) as workhorse is useful and has some advantages such as good viability, one-stage reconstruction and carotid protection. The objective of this study was to review the role and indication of PMMCF in this era of potent free flaps for head and neck reconstruction. Patients and Methods: Sixty one PMMCF and one hundred forty six free flaps used for head and neck reconstruction between 1991 and 2001 were reviewed retrospectively. We compared the applied sites of flap, the flap failure rate and complications. Results: Contrary to the free flap, use of PMMCF has gradually decreased after the middle of 1990s. PMMCF were mainly used for mucosal defect(33cases, 54.1%) and cervical skin defect(22cases, 36.1%) and free flap were mainly used for mucosal defect(129cases, 88.4%). In point of use of PMMCF according to years, from 1991 to 1997, 30cases(70%) are used to reconstruct mucosal defect and 12cases(29%) are used to reconstruct skin defect. But from 1998 to 2001, only 2cases(10.5%) are used to reconstruct mucosal defect and 13cases(68.4%) are used to reconstruct neck skin defect. In case of free flap, from 1991 to 1997, 41cases (87%) are used to reconstruct mucosal defect and from 1998 to 2001 88cases(89%) are used as same purpose. Three major necrosis (more than 50%) deveolped in 61 PMMCF (4.9%) and three major necrosis developed in 146 free flaps(2.1%). Conclusion: PMMCF is no longer flap of choice for primary reconstruction but it is a still one of a good tool in some head and neck reconstruction such as covering single wide defect of face or neck skin, back-up procedure of free flap, postoperative status, treatment of pharyngocutaneous fistula and covering vital structure.

• Journal of The Korean Association For Science Education
• /
• v.36 no.2
• /
• pp.317-324
• /
• 2016

This study aims to investigate the motivation for science learning of 3rd year high school students who choose different majors from their track. A total of 2,012 high school 3rd year students participated in this study. We used Science Motivation Questionnaire II (Glynn et al., 2011) to measure the students' science motivation and performed Rasch analysis, MANOVA and logistic regression analysis. First, results showed that 11.5% of students in the science track switched their pathway to a non-STEM major and 14.3% of students in the humanities track switched to a STEM major. In addition, there were gender differences in switching majors. Second, we found a significant difference in science motivation between two groups of students switching their major only in career motivation. Third, science motivation was the significant predictor of STEM major choice; in particular, career motivation was the most influential variable. Based on these results, we proposed that prediction of and paying close attention to students' career motivation are required before making decisions on which track to take.