• The Journal of Information Technology
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• v.7 no.1
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• pp.69-86
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• 2004

In this paper, a conceptual framework describing the dynamics of click and mortar businesses is provided. It directs our attention to the many potential sources of synergy that are available to firms that choose to integrate e-commerce with their existing traditional forms of business. It further emphasizes the many actions that firms can take to minimize channel conflicts and help achieve the benefits of synergy. Finally, it describes four categories of synergy-related benefits from the integration of e-commerce with traditional businesses, including potential cost saving, gains due to enhanced differentiation, improved trust, and potential extensions into new markets. The utility of the framework was demonstrated using the case of an electronics retailer that has chosen to tightly integrate its large chain of retail stores with its Web-based electronic store. The framework was also used to develop a series of propositions that can guide future empirical research. The discussion points to the need to develop new types of metrics to better judge the contributions of e-commerce channels, and provides some guidance for future empirical research that can test whether, and under what conditions, integrated click and mortar business models work well. Thus, the purpose of this study is to present the combining physical and virtual presence in e-commerce.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.2
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• pp.471-476
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• 2015

In this paper, we propose an energy efficient hybrid MAC protocol for multi-hop wireless sensor networks. The proposed MAC protocol used a hybrid mechanism, in which contention-based MAC protocol and contention free MAC protocol are combined. The sensor nodes located far from the sink node usually send few data packet since they try to send measured data by themselves. So contention-based MAC protocol is useful among them. But other nodes located near sink node usually have lots of data packets since they plays as a relay node. Contention-based MAC protocol among them is not suitable. Using contention-based MAC protocol in heavy data traffic environment, packet collisions and transmission delay may increase. In this paper, slot assignment between sender nodes by sink node is used. The proposed mechanism is efficient in energy and latency. Results showed that our MAC protocol outperformed other protocol in terms of data packet delivery delay and energy consumption.

• Journal of Korean Society of Transportation
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• v.20 no.2
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• pp.105-115
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• 2002

For many rears, traffic accident statistics are the most direct measure of safety for a signalized intersection. However it takes more than 2 or 3 yearn to collect certain accident data for adequate sample sizes. And the accident data itself is unreliable because of the difference between accident data recorded and accident that is actually occurred. Therefore, it is rather difficult to evaluate safety for a intersection by using accident data. For these reasons, traffic conflict technique(TCT) was developed as a buick and accurate counter-measure of safety for a intersection. However, the collected conflict data is not always reliable because there is absence of clear criteria for conflict. This study developed objective and accurate conflict criteria, which is shown below based on traffic engineering theory. Frist, the rear-end conflict is regarded, when the following vehicle takes evasive maneuver against the first vehicle within a certain distance, according to car-following theory. Second, lane-change conflict is regarded when the following vehicle takes evasive maneuver against first vehicle which is changing its lane within the minimum stopping distance of the following vehicle. Third, cross and opposing-left turn conflicts are regarded when the vehicle which receives green sign takes evasive maneuver against the vehicle which lost its right-of-way crossing a intersection. As a result of correlation analysis between conflict and accident, it is verified that the suggested conflict criteria in this study ave applicable. And it is proven that estimating safety evaluation for a intersection with conflict data is possible, according to the regression analysis preformed between accident and conflict, EPDO accident and conflict. Adopting the conflict criteria suggested in this study would be both quick and accurate method for diagnosing safety and operational deficiencies and for evaluation improvements at intersections. Further research is required to refine the suggested conflict criteria to extend its application. In addition, it is necessary to develope other types of conflict criteria, not included in this study, in later study.

• Journal of architectural history
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• v.10 no.4 s.28
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• pp.77-92
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• 2001

현대의 건축시기는 다원성의 시기 또는 복합성의 시기라고 불리운다. 모더니즘과 포스트모더니즘의 시기를 거치며 다양한 형태적 실험의 과정을 겪었고 수많은 이데올로기와 이론들로 무장된 논쟁의 역사도 갖게 되었다. 이러한 현대건축의 다양성은 건축디자인이라는 전문직의 사회에 기여하는 역할을 반추(反芻)함과 동시에 다변하는 인간사고의 역동성을 반영하고 있다. 건축관련 책자나 저널 등에서 흔히 발견할 수 있는 Neo-Classicism, Deconstructivism, Minimalism, High-Tech, New Moderns 등등의 건축양식들은 스타일을 지칭하는 언어라기보다는 건축적 사고를 지칭하는 언어라고 할 수 있다. 결국 건축디자인이라는 작업은 인간을 둘러 싼 건조환경의 생성에서 출발하는 것이므로 건축적 사고방식은 그 시기의 사회현상과 밀접한 관계를 맺게 된다. 20세기 말부터 불어닥친 디지털 문화의 사회변혁은 전 세계를 하나의 채널로 엮게 되었고, 이러한 영향들은 지역과 민족, 그리고 종교적인 요소들까지도 혼합하여 국경을 초월한 미래의 새로운 이상들을 꿈꾸게 되었다. 19세기 산업혁명과 함께 급속히 벨라진 인류문명의 진보는 필수적으로 세계화를 동반하는 것이고, 세계화와 지역성사이의 괴리를 통해 나타나는 문화적 비판과 충돌은 아직도 진행상태인 것이다. 세계화라는 통염은 문명의 보편성을 기반으로 하며 전통문화의 파괴가 뒤따를 수밖에 없는데, 현재와 같이 IT혁명을 통해 급속도로 빨라진 세계문화의 교류는 한 국가가 뿌리를 내리고 있는 문화적 유산이라는 토양을 포기하여야 할 단계에 와 있다고 논평할 정도이다. 여기서 건축은 문화적 상징으로 작용하게 되는데, 그것이 심미적이든 관습적이든 또는, 경제적이든 건축가는 해답의 제시라는 임무에 직면하게 된다. 20세기에 진행된 모더니즘의 건축은 구조와 공간에 대한 고전건축의 숙원을 고덕건축이 이룬 것처럼 15세기 르네상스 시대로부터 진행된 형태와 공간, 기능, 그리고 아름다움과 기술(technology) 또는 경제성 등에 대한 건축적 의문과 탐구를 일단락지었다고 할 수 있다. 이러한 모더니즘의 한복판에 Mies van der Rohe라는 거장이 깊은 발자국을 남기며 한 시대를 이루었고 그가 남긴 시대정신의 이념과 가치를 Miesianism이라고 부른다. 실용성과 도덕성을 근본으로 하는 Miesianism은 대중에 호소하는 미적 표현주의를 부정하고 지역정서를 중시하는 문맥적 접근방식을 경시함으로써 보편화라는 현상을 불러일으킨 국제주의 양식의 한 부류로 비판을 받아왔다. 즉, Miesianism의 단순하고 강렬한 외형적 요소는 그것이 내포하는 기술적 합리성이나 공간적 완결성을 무시한 채 전 세계에 영향을 미쳤고 동시에 지역적 저항을 받게 되었다. 시카고 및 전 세계의 Miesian들, 즉 Mies van der Rohe의 제자들이나 그로부터 영향을 받은 수많은 건축가들은 이러한 저항과 비판에 직면하게 되며 새로운 사고의 시대적 요구 앞에 고뇌하게 된다. 한국에서는 1978년 Mies van der Rohe의 제자인 김종성이 미국에서 서울로 돌아와 '서울건축컨설탄트'를 설립하며 본격적으로 Miesianism의 규범적 건축론을 설파하기 시작하였다. 이른바 시카고 국제주의학파의 건축전수라고 할 수 있는데 '서울건축컨설탄트'를 통하여 배출된 김종성의 제자들은 명쾌하고도 간결한 건축해법의 경험을 토대름대로의 정체성을 갖고자 노력하였으나 결국 다원적 가치를 요구하는 시대적 흐름 속에 혼란을 겪고 있는 것 또한 사실이다. 본 연구는 Miesianism의 기원을 밝히고 그것의 실수와 오류를 밝힘과 동시에 현대의 여러 가지 건축유형들과 비교하여 봄으로써 Post-Miesianism의 실체와 그 미래에 대하여 고찰하여 보고자 한다. 미스의 유산이라고 할 수 있는 Miesianism의 요체는 첫째, Schinkel로부터 이어받은 시대정신의 사명감, 둘째, Berlage가 전해준 전문가로서의 도덕성을 바탕으로 하여 이루어진 기술적 합리성의 실현, 그리고 마지막으로 그 당시의 추상예술에 대한 이해로써 받아들인 nee-Suprematism의 아방 가르데적인 자세라고 할 수 있다. 그러나 이것들을 전파하고 수용하는 과정에서 미스적인 단순하고 명쾌한 외관이 더욱 강한 인상을 남기게 되었고 또한 미스가 현대성의 본질이라고 믿는 기술의 전수는 모든 외관을 동일하게 만드는 International Style로서의 보편적 획일성을 초래하였다. Mies van der Rohe의 강력하고 규범적인 dogma는 그의 제자들에게는 강렬한 카리스마로 각인되었고, Mies가 원한 것이 아닐지라도 그들을 하나의 틀 속에 가두는 영향력을 행사하였다. 2세대이든 3세대이든 기술적 합리성과 추상적 단순미라는 믿음을 맹목적으로 추종할 때 그들은 Miesian으로 남아있게 되며, 거기서 벗어났을 때 non-Miesian, 또는 배신자로 취급하기까지 하였다. 이것은 미스의 제자들에게 강한 족쇄가 되어 형태적 또는 개념적 변화의 시도를 어렵게 하였고 시대적 요구에 부응하지 못한다는 평가에 이르게 되었다. 문화의 다양성과 역동성을 인정함과 동시에 Miesianism에 대한 새롭고 시대에 적합한 해석을 기대하게 되는데, 이러한 기대 속에서 우리는 Post-Miesianism이라는 새로운 유형을 엿볼 수 있게 된다. Post-Miesianism의 징후를 현대의 다양한 건축유형에서 발견할 수 있는데, High-Tech의 구축적이고 정밀한 건축 기술적 해법과 Minimalism의 반복성을 통한 추상미의 표현 등에서 뿐만이 아니라 Post-Modernism의 인간성의 추구나 문맥적 고려, 또는 해체주의의 형이상학적이고 아방가르데적인 실험주의 정신까지조차 Post-Miesianism이 공유할 수 있는 부분이 있다고 보여진다. 또한, 미스의 영향이 2세대, 3세대의 건축가들에게 미치면서 여러 방향으로 변질되어 가는 것을 우리는 발견할 수 있으며 그러한 시대성에 적응하는 시도들이야말로 새로운 미래를 향한 Post-Miesianism의 실체인 것이다. Mies가 말하였듯이 한 시대의 끝은 그 시대가 완전히 이해되었을 때이며, 모더니즘의 숙제는 아직 해결되지 않았으므로 Miesianism의 탐구는 Post-Miesianism이라는 새로운 주제로 계속될 것이다. 이를 통하여 21세기 디지털 문명의 시대 속에서 현대건축이 안을 수밖에 없는 보편성과 지역성의 충돌이라는 문제의 해결에 한 발걸음 다가갈 수 있기를 기대하여 본다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.714-721
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• 2016

This paper proposes a simple process to fabricate tin and brass metal discs with a large surface area from molten droplets for the wet-refining process of nonferrous metals by assuming they have precious metal elements. To optimize the droplet condition in a graphite crucible, the appropriate nozzle size was determined using a simulation program (STAR-CCM+) by varying the diameters (0.5, 1.0, and 2.0 mm). The simulation results showed that both tin and brass do not fall out with a 0.5 mm diameter nozzle but they do fall out in continuous ribbon mode with a 2.0 mm nozzle. Only the 1.0mm nozzle was expected to fabricate droplets. Finally, solidified metal discs were fabricated successfully with the 1.0 mm nozzle within 10 minutes by impacting the droplets with a cooling water flowing over a Ti plate placed at the $40^{\circ}$ falling direction. The weight, average thickness, and surface area of the tin discs were 0.15 g, $107.8{\mu}m$, and $3.71cm^2$, respectively. The brass discs were 1.16 g, $129.15{\mu}m$, and $23.98cm^2$, respectively. The surface area of the tin and brass disc were 8.2 and 17.6 times the size of the tin and brass droplets, respectively. This process for precious metal extraction is expected to save cost and time.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.11
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• pp.3121-3129
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• 2009

Conventional marine radar systems utilize pulse radar which is capable of high-power transmissions and is effective for remote detection purposes. A pulse radar is most commonly used on medium or large vessels due to its expensive installation and maintenance costs. I propose the use of a Frequency Modulated Continuous Wave (FMCW) radar system operated at low-power and high-resolution instead of the conventional pulse-radar based system. The transmitted and received signals of the FMCW radar system were theoretically analyzed and radar signal processing design and simulation experiments were performed to detect the range and speed. Intermediate Frequency (IF) signal mixed with virtual transmit and receive signals were generated to perform FMCW radar signal processing simulations where the IF signal underwent noise reduction through a lowpass filter. The maximum frequency was derived through the sample interval of the FFT size instead of using A/D converter. This maximum frequency was used to get the frequency range and frequency speed which were in turn used to calculate the range and speed. The virtual beat frequency generated using MATLAB is utilized to analyze the beat frequency used in the actual FMCW radar system signal processing. The differences in the range and speed of the beat frequency signals are processed and analyzed.

• Korean Journal of Agricultural Science
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• v.7 no.2
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• pp.156-168
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• 1980

The air-center nozzles, being specially designed to supply air into the central part of water stream at seven levels of air volume, were tested for spray deposit pattern and flow-rate at each of the twelve pressure levels ranging from $0.35kg/cm^2$ (5 psi) to $6.33kg/cm^2$ (90 psi) in comparison with those of standard nozzles. The air-center nozzles produced comparatively more stable spray deposit patterns than the standard nozzles. The spray deposit patterns of the air-center nozzle were concentrated gradually in the central region with increase of air volume as a component of spray mixture. The degree of concentration of spray deposit on the central region from the air-center nozzle was higher than that of the standard nozzle, which suggested the possibility of obtaining farther travel distance spraying system at a given performance level. The flow rate of the air-center nozzle was not as much as that of the standard nozzle due to the air within certain limits. The rate of decrease of water flow became smaller with an increase in operating pressure although it changed rapidly in the beginning stage, ranging up to two or three percent of the air flow rate due to the compressive properties of air.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.1 no.1
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• pp.58-69
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• 2002

Most of the traffic accidents are a rear-end collision and a clash generated in the signalized intersection on the local roads. So, it is demanded that the high-quality of signal control and dilemma zone control. According to the cases generated by foreign countries, we established the strategies which are composed of Volume-Density Control, strategy of the dilemma zone control using R-detector (microwave detector) In Japan and EC-DC Control. MOEs(Measure of effectiveness) are car numbers in the dilemma zone , max-out probability in the safe side and the average stopping delay in the progress side. We choose a signalized intersection in rural highway to analyze the effect of the strategies and practiced an on-the-spot survey. The result of the survey is applied to the basic data in the simulator. Consequently, strategy of the dilemma zone control using R-detector(microwave detector) in Japan is the best effective in the safe side and EC-DC control is the best in the progress side. Based on the result, we developed the effective strategy of the signal control . This strategy is composed of the strategy of Japan and the detector on the stopping line used in the EC-DC control. On the result of the analysis, new strategy is the best effective in two sides.

• The Journal of the Petrological Society of Korea
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• v.17 no.4
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• pp.222-230
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• 2008

Intruding ages for the Jurassic(${\sim}Triassic$) granites in South Korea can be reestablished as $210{\sim}170\;Ma$ and $180{\sim}160\;Ma$ according to the tectonic provinces of magma emplacement. Most Jurassic granites in the Gyeonggi massif have the intrusion ages of $180{\sim}160\;Ma$, indicative of middle Jurassic igneous activity. On the other hand the intrusion ages ($210{\sim}170\;Ma$) for the Jurassic granites in the Yeongnam massif represent late Triassic to middle Jurassic igneous activity. Using the concept of granite suite/supersuite, the Jurassic granites in South Korea can be hierarchically divided into two supersuites and two suites. Huge batholith of NE-SW direction in the Gyeonggi massif could be designated to be 'Gyeonggi Supersuite', which was originated from the mixture of igneous protolith and more evoloved crustal materials and formed in the post-orogenic environment after collision of the north China and south China blocks. There are one supersuite and two suites in the Yeongnam massif 'Yeongnam Supersuite' could be designated from the NE-SW trend batholith in the massif. This supersuite was originated from the mixture of igneous protolith and evolved crustal materials. Granitic rocks between Andong and Girncheon areas could be defined as 'Andong Suite'. This suite was originated from the mixture of depleted mantle and igneous protolith. The Daegang and Hamchang granties could be designated as 'Daegang Suite'. This suite was formed in the anorogenic environment which was different from the orogenic environment of the other supersuite/suite in the Yeongnam massif.

• Clean Technology
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• v.27 no.1
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• pp.39-46
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• 2021

A road structure washing vehicle equipped with a 4 HP, 80 LPM ultrafine bubble generator was used to clean a tunnel wall and the surface of the surrounding structure, consisting of concrete and tiles, in a heavy traffic area around an apartment complex in the city. Ultrafine bubbles were generated by supplying air at 2 to 3 LPM and using a specially designed nozzle, whereas fine bubbles made by an impeller in a gas-liquid mixing self-priming pump were produced with an average diameter of 165.4 nm and 6.81 × 107 particles mL-1. Using a high pressure washer gun that can perform high-pressure cleaning at 150 bar and 30 LPM, ultrafine bubbles were used to wash dust adsorbed on the surface of the road structures. The experimental analysis was divided into before and after washing. The samples were analyzed by applying ISO 8502-3 to measure surface contamination of dust adsorbed on the surface. Using the transparent tape attached to the surface, the removal rate was calculated by measuring the weight of the dust, and the number of particles was calculated using the gravimetric method and the software, ImageJ. The results of the experiment showed that the number of dust particles adsorbed on the tile wall surface before and after washing were 3,063 ± 218 particles mL-1 and 20 ± 5 particles mL-1, respectively, with weights of 580 ± 82 mg and 13 ± 4 mg. Particles on the surface of the concrete structure before and after washing were 8,105 ± 1,738 particles mL-1 and 39 ± 6 particles mL-1, respectively, with weights of 1,448 ± 190 mg and 118 ± 32 mg.