• Progress in Medical Physics
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• v.10 no.3
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• pp.133-140
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• 1999

In this paper, as a preliminary study for developing a full 3D electron dose calculation algorithm, We developed 2.5D electron dose calculation algorithm by extending 2D pencil-beam model to consider three dimensional geometry such as air-gap and obliquity appropriately. The dose calculation algorithm was implemented using the IDL5.2(Research Systems Inc., USA), For calculation of the Hogstrom's pencil-beam algorithm, the measured data of the central-axis depth-dose for 12 MeV(Siemens M6740) and the linear stopping power and the linear scattering power of water and air from ICRU report 35 was used. To evaluate the accuracy of the implemented program, we compared the calculated dose distribution with the film measurements in the three situations; the normal incident beam, the 45$^{\circ}$ oblique incident beam, and the beam incident on the pit-shaped phantom. As results, about 120 seconds had been required on the PC (Pentium III 450MHz) to calculate dose distribution of a single beam. It needs some optimizing methods to speed up the dose calculation. For the accuracy of dose calculation, in the case of the normal incident beam of the regular and irregular shaped field, at the rapid dose gradient region of penumbra, the errors were within $\pm$3 mm and the dose profiles were agreed within 5%. However, the discrepancy between the calculation and the measurement were about 10% for the oblique incident beam and the beam incident on the pit-shaped phantom. In conclusions, we expended 2D pencil-beam algorithm to take into account the three dimensional geometry of the patient. And also, as well as the dose calculation of irregular field, the irregular shaped body contour and the air-gap could be considered appropriately in the implemented program. In the near future, the more accurate algorithm will be implemented considering inhomogeneity correction using CT, and at that time, the program can be used as a tool for educational and research purpose. This study was supported by a grant (＃HMP-98-G-1-016) of the HAN(Highly Advanced National) Project, Ministry of Health & Welfare, R.O.K.

• Korean Security Journal
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• no.39
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• pp.319-353
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• 2014

Cyber-based technologies are now ubiquitous around the glob and are emerging as an "instrument of power" in societies, and are becoming more available to a country's opponents, who may use it to attack, degrade, and disrupt communications and the flow of information. The globe-spanning range of cyberspace and no national borders will challenge legal systems and complicate a nation's ability to deter threats and respond to contingencies. Through cyberspace, competitive powers will target industry, academia, government, as well as the military in the air, land, maritime, and space domains of our nations. Enemies in cyberspace will include both states and non-states and will range from the unsophisticated amateur to highly trained professional hackers. In much the same way that airpower transformed the battlefield of World War II, cyberspace has fractured the physical barriers that shield a nation from attacks on its commerce and communication. Cyberthreats to the infrastructure and other assets are a growing concern to policymakers. In 2013 Cyberwarfare was, for the first time, considered a larger threat than Al Qaeda or terrorism, by many U.S. intelligence officials. The new United States military strategy makes explicit that a cyberattack is casus belli just as a traditional act of war. The Economist describes cyberspace as "the fifth domain of warfare and writes that China, Russia, Israel and North Korea. Iran are boasting of having the world's second-largest cyber-army. Entities posing a significant threat to the cybersecurity of critical infrastructure assets include cyberterrorists, cyberspies, cyberthieves, cyberwarriors, and cyberhacktivists. These malefactors may access cyber-based technologies in order to deny service, steal or manipulate data, or use a device to launch an attack against itself or another piece of equipment. However because the Internet offers near-total anonymity, it is difficult to discern the identity, the motives, and the location of an intruder. The scope and enormity of the threats are not just focused to private industry but also to the country's heavily networked critical infrastructure. There are many ongoing efforts in government and industry that focus on making computers, the Internet, and related technologies more secure. As the national intelligence institution's effort, cyber counter-intelligence is measures to identify, penetrate, or neutralize foreign operations that use cyber means as the primary tradecraft methodology, as well as foreign intelligence service collection efforts that use traditional methods to gauge cyber capabilities and intentions. However one of the hardest issues in cyber counterintelligence is the problem of "Attribution". Unlike conventional warfare, figuring out who is behind an attack can be very difficult, even though the Defense Secretary Leon Panetta has claimed that the United States has the capability to trace attacks back to their sources and hold the attackers "accountable". Considering all these cyber security problems, this paper examines closely cyber security issues through the lessons from that of U.S experience. For that purpose I review the arising cyber security issues considering changing global security environments in the 21st century and their implications to the reshaping the government system. For that purpose this study mainly deals with and emphasis the cyber security issues as one of the growing national security threats. This article also reviews what our intelligence and security Agencies should do among the transforming cyber space. At any rate, despite of all hot debates about the various legality and human rights issues derived from the cyber space and intelligence service activity, the national security should be secured. Therefore, this paper suggests that one of the most important and immediate step is to understanding the legal ideology of national security and national intelligence.

• Korean Security Journal
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• no.18
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• pp.119-141
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• 2009

Administrative execution by proxy is one of forced executions of administration and is also called as "enforced execution by proxy" in which administration institutions or the third party executes by proxy on behalf of parties who did not execute obligations under administration law and files claims to compensate expenses required in the proxy execution. Despite the actual site of administrative execution by law, social problems are generated because various violence and behaviors of infringement of human rights between executer and obligator are rampant and thus causing human damages since forced execution by physical force is carried out and cases of police indictments and petition to human rights committee are gradually increasing. Majority of people mobilized in this actual site of violence are supplied by private security companies which provide service contract and mobilization of people without qualification of guards or security service and irrational execution by proxy and violent actions by so-called service hooligans connected to violence organizations are now becoming social issues. In these actual sites of violence, structurally very complicated problems such as economic rights, right of residence, struggle for living, and intervention by outsiders are contained. This thesis has analyzed causes of outbreaks of violence and discussed about improvement countermeasure by paying attention to mobilization of people by private security companies. As the result, through revision and improvement of laws and systems, execution institution and policemen must be present at actual sites of execution by proxy to control physical execution of private security companies to be carried out legally and when violent collisions are occurring, it shall be stipulated that police should immediately intervene. Practices of execution by proxy of execution administration institutions shall be avoided and causes of occurrences of violence shall be eliminated by discrete decisions of execution by proxy, elimination of service contract conditions focused on accomplishments, and stipulation of responsibility of execution institutions when problems occur. Practices of solving petitions through collective actions of obligators shall be eliminated and strict enforcement of laws such as disturbance of official execution or compensation claims for expenses of execution by proxy must be carried out and intervention by the third parties must be intercepted. Mobilization of manpower by security companies shall be limited to people with prior registration who have acquired and finished qualification and education by security business law and before putting them on actual sites, it shall be obliged that execution plan with clear written records of working location, mission, and work rules must be submitted in advance to police station in charge and also they must be controlled to follow laws and statutes such as uniform and equipments. In addition, personal criminal responsibility for violent actions must be clearly stipulated and advanced securing soundness of security companies such as limits of service contracts with records of accidents is required. Order placement behaviors of special organizations under the pretext of rehabilitation business must be eradicated and companies with capability and strong intention of observation of laws must be able to receive orders by intercepting chains of contracts and sub-contracts. Issues of improvement countermeasure of social problem, living, and compensation including rights of residence and environment are excluded from the discussion.

• Progress in Medical Physics
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• v.26 no.2
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• pp.87-92
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• 2015

The gated RapidArc may produce a dosimetric error due to the stop-and-go motion of heavy gantry which can misalign the gantry restart position and reduce the accuracy of important factors in RapidArc delivery such as MLC movement and gantry speed. In this study, the effect of stop-and-go motion in gated RapidArc was analyzed with varying gating window time, which determines the total number of stop-and-go motions. Total 10 RapidArc plans for treatment of liver cancer were prepared. The RPM gating system and the moving phantom were used to set up the accurate gating window time. Two different delivery quality assurance (DQA) plans were created for each RapidArc plan. One is the portal dosimetry plan and the other is MapCHECK2 plan. The respiratory cycle was set to 4 sec and DQA plans were delivered with three different gating conditions: no gating, 1-sec gating window, and 2-sec gating window. The error between calculated dose and measured dose was evaluated based on the pass rate calculated using the gamma evaluation method with 3%/3 mm criteria. The average pass rates in the portal dosimetry plans were $98.72{\pm}0.82%$, $94.91{\pm}1.64%$, and $98.23{\pm}0.97%$ for no gating, 1-sec gating, and 2-sec gating, respectively. The average pass rates in MapCHECK2 plans were $97.80{\pm}0.91%$, $95.38{\pm}1.31%$, and $97.50{\pm}0.96%$ for no gating, 1-sec gating, and 2-sec gating, respectively. We verified that the dosimetric accuracy of gated RapidArc increases as gating window time increases and efforts should be made to increase gating window time during the RapidArc treatment process.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.2
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• pp.1-12
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• 2015

This study explores urban gardening and garden culture in residential area as an everydayness that has been overlooked during the modern period urbanization and investigates the meaning and value of urban gardening from the perspective of urban formations and growth in spontaneous urban residential area, Haebangchon. The result identified that urban gardening as a meaning of contemporary culture is a new clue to improving the urban physical environment and changing the lives and community network of residents. Haebangchon is one of the few remaining spontaneous habitations in Seoul, and was created as a temporary unlicensed shantytown in 1940s. It became the representative habitation for common people in downtown Seoul through the revitalization of the 60s and the local reform through self-sustaining redevelopment projects during the 70s through the 90s. This area still contains the image of times during the 50s to the 60s, the 70s to the 80s and present, with the percentage of long-term stay residents high. Within this context, the site is divided into third quarters, and the research undertaken by observation and investigation to determine characteristics of urban gardening as an everydayness. It can be said that urban gardening and garden culture in Haebangchon is a unique location culture that has accumulated in the crevices of the physical condition and culture of life. These places are an expression of resident's desires that seeking out nature and gardening as revealed in densely-populated areas and the grounds of practical acting and participating in care and cultivation. It forms a unique, indigenous local landscape as an accumulation of everyday life of residents. Urban gardens in detached home has retained the original function of the dwelling and the garden, or 'madang', and takes on the characteristic of public space through the sharing of a public nature as well as semi-private spatial characteristic. Also, urban gardens including small kitchen garden and flowerpots that appear in the narrow streets provide pleasure as a part of nature that blossoms in narrow alley and functions as a public garden for exchanging with neighbors by sharing produce. This paper provides the concept of redefining the relationship between the private-public area that occurs between outside spaces that are cut off in a modern city.

• Journal of Food Hygiene and Safety
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• v.34 no.1
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• pp.1-12
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• 2019

The health benefits associated with consumption of fresh produce have been clearly demonstrated and encouraged by international nutrition and health authorities. However, since fresh produce is usually minimally processed, increased consumption of fresh fruits and vegetables has also led to a simultaneous escalation of foodborne illness cases. According to the report by the World Health Organization (WHO), 1 in 10 people suffer from foodborne diseases and 420,000 die every year globally. In comparison to other processed foods, fresh produce can be easily contaminated by various routes at different points in the supply chain from farm to fork. This review is focused on the identification and characterization of possible sources of foodborne illnesses from chemical, biological, and physical hazards and the applicable methodologies to detect potential contaminants. Agro-chemicals (pesticides, fungicides and herbicides), natural toxins (mycotoxins and plant toxins), and heavy metals (mercury and cadmium) are the main sources of chemical hazards, which can be detected by several methods including chromatography and nano-techniques based on nanostructured materials such as noble metal nanoparticles (NMPs), quantum dots (QDs) and magnetic nanoparticles or nanotube. However, the diversity of chemical structures complicates the establishment of one standard method to differentiate the variety of chemical compounds. In addition, fresh fruits and vegetables contain high nutrient contents and moisture, which promote the growth of unwanted microorganisms including bacterial pathogens (Salmonella, E. coli O157: H7, Shigella, Listeria monocytogenes, and Bacillus cereus) and non-bacterial pathogens (norovirus and parasites). In order to detect specific pathogens in fresh produce, methods based on molecular biology such as PCR and immunology are commonly used. Finally, physical hazards including contamination by glass, metal, and gravel in food can cause serious injuries to customers. In order to decrease physical hazards, vision systems such as X-ray inspection have been adopted to detect physical contaminants in food, while exceptional handling skills by food production employees are required to prevent additional contamination.

• Journal of the Korean Institute of Landscape Architecture
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• v.49 no.6
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• pp.49-63
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• 2021

The Forest Visitor Centers for Little Children who means preschoolers is an educational facility that achieves holistic growth by experiencing forests, and it should not be completed by installing specific facilities in the forest environment, but should be a space where preschoolers can play freely in the forest environment themselves. This study comprehensively evaluated the current status of Seoul Forest Visitor Centers for Little Children and suggested space improvement measures to enhance the effectiveness of forest experience. Through the theoretical review, seven spatial elements that enhance the effect of forest experience and six areas composing outdoor play areas were derived to prepare an analysis table for current status evaluation, and field survey studies were conducted on 24 centers in Seoul. Through expert interviews, the physical status was examined from the perspective of childhood education and the experiences of the users were summarized. As a result of the study, the Seoul Forest Visitor Center for Little Children is classified into six types according to the location characteristics and spatial structure, and has the characteristics of each type. The effectiveness of forest experience can be enhanced by identifying and revealing the environmental strengths of individual centers. In the case of outdoor experience learning zones, the proportion of exercise play areas was very large. By evenly organizing the forest experience space for each area, it will be possible to provide more diverse experiences to preschoolers. However, the status of uniform facility-oriented cannot be viewed as a fragmentary factor that lowers the effect of forest experience. The key to increasing the effect of forest experience by inducing creative activities is the spatial composition that considers the surrounding natural environment. Facilities should be a medium to help preschoolers' interest move into the forest. This study prepared data to understand the average physical status of the Seoul Forest Visitor Center for Little Children and suggested space improvement measures to increase the effectiveness of forest experience. This can be used as basic data for research to improve the quality level of the Seoul Forest Visitor Center for Little Children about 10 years after the project was implemented.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.69 no.1
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• pp.34-48
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• 2024

The objective of this study was to evaluate the safety of biodegradable mulching films in soybean (Glycine max) cultivation by measuring their effects on crop growth and yield, film decomposition and soil chemical and physical properties. In 2022 and 2023, plant height, branch number, chlorophyll contents, yield components, and yield of soybean did not vary significantly in areas using PE films and biodegradable mulching films. The light transmission rate of the biodegradable mulching films ranged from 6.4 to 15.8% when measured 112 days after soybean transplanting, and was higher, on average, in 2023 than in 2022. In both years, degradation of the biodegradable mulching films began 20 days after soybean transplantation and increased over time. In addition, remains of biodegradable mulching films were present in fields at soybean harvest and remained until 50 days after harvest. Decomposition rates of the biodegradable mulching films at 112 days after soybean transplanting ranged from 9.8 to 26.7% in 2022 and 13 to 36% in 2023. Although soil pH and EC varied based on the year and timing of measurements, there was no significant difference between areas that used biodegradable mulching films and PE films. Soil organic matter, nitrate and exchangeable cation contents such as Ca, Mg, and K were not significantly different in areas that used both PE films and biodegradable films. However, significantly higher levels of available phosphoric acid content were measured in areas that used biodegradable mulch films E, S, and T. Regardless of which films were used, there were no significant differences in the soil's physical properties. In 2022 and 2023, there was no difference between areas that used biodegradable mulch films and PE films. However, soil temperature in mulched areas was 2℃ higher and soil moisture was 5-15% higher than in non-mulched areas. Barley growth was not affected by being planted in soil that had been used for soybean cultivation with biodegradable films. Therefore, the biodegradable mulch films used in this study can be used without negatively affecting the growth, yield, and soil environment of soybeans.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.52-52
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• 2017

연구목적: 생산자와 소비자의 물리적 사회적 거리가 가까워지고, 1일 유통체계 준수에 의한 높은 신선도 유지, 먹거리에 대한 생산자와 생산정보 공유에 의한 농산물 안전성 향상 등 여러 장점 때문에 늘어나고 있는 로컬 푸드의 지속발전을 모색하고자 로컬 푸드 참여농가의 농작업 어려움 조사 및 기계화 방안 제시 조사방법: 전북 완주군 소재 용진농협에서 운영 중인 로컬 푸드 직매장에 농산물을 공급하는 농업인 21인을 대상으로 2016년 11월에 로컬 푸드의 어려운 점, 주요 생산품목, 가장 힘든 농작업, 기계화가 시급한 농작업, 농기계 도입에 어려운 점, 의견 및 건의사항을 설문 조사 분석하였음 결과 및 고찰: 로컬 푸드 참여 농가들은 4~5개 품목을 소량 생산하고, 농가에서 수확 소포장 라벨 부착 후 매장에 직접 진열하고 있었음. 농협은 정선 선별기, 소형 도정기, 포장기, 바코드 기계 등을 설치하여 농가 공동이용, 안전성 신선도 관리 등 교육, 스마트폰 앱을 매장 재고 현황을 농업인에게 실시간으로 제공 등 지원하고 있음. 조사에 응한 농업인 21명 중 60대(13명) > 50대(5명) > 70대(3명)로 모두 50대 이상이었음. 어려운 점에 대한 물음에 대해서는 '판매가 어렵다'(45%) > '인력이 부족하다'(40%) > '생산비가 많이 든다'(8.5%) > 기타(6.5%) 순이었음. '인력부족'은 파종과 수확 시기에 노동력이 집중적으로 필요한 것에 기인하고, 경지 규모가 다소 큰 농가에서는 농사일을 전문으로 하는 외국인 노동자를 고용함으로 노동력 부족 문제를 해소하지만, 소규모 농가는 품삯을 주고 고용할 경우 오히려 적자이기 때문에 고되더라도 자체 노동력으로 해결하고 있는 것으로 조사되었음. 가장 힘든 작업은 수확(81%) > 파종 정식(19%)으로 수확이 절대적으로 힘든 작업이라고 응답하였고, 기계화가 시급한 작업은 수확(71%) > 파종 정식(29%)으로 응답하였음. 힘든 이유로는 적기에 수확을 끝내야 상품성을 인정받을 수 있기 때문에 단기간에 많은 노동력이 요구된다고 응답하였음. 농기계 도입에 어려운 원인으로는, '적합한 수확기계가 없다'(48%)와 '재배면적이 적어 필요성을 못 느낀다'(29%)가 대부분이었고, 이밖에 '가격이 비싸다'(10%), '기계 정확도가 떨어진다'(10%), '기계 조작이 어렵다'(5%)로 나타났음. 결론: 로컬 푸드 참여 농가를 대상으로 농작업 기계화 현황에 대하여 조사하였음. 로컬 푸드의 지속 발전을 위한 방안을 제시하면; 첫째, 중 소농을 위한 수확기 개발이 가장 시급한 것으로 조사되었고, 둘째, 농기계가 아니더라도 우선 힘든 일을 해소하면서 편하게 자세를 유지할 수 있는 작업 보조기구 또는 편이장비의 개발 보급이 필요함. 셋째, 농가의 영세성과 지역의 특성을 고려하여 기술센터 농기계임대사업이나 시군 보조사업을 통해서 소형 농기계, 농기구, 보조 및 편이장비 보급이 확대되어야 함.

• Archives of design research
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• v.20 no.3 s.71
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• pp.119-128
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• 2007

With the development of digital technologies, CAID became an essential part in the industrial design process. Creating photo-realistic images from a virtual scene with 3D models is one of the specialized task for CAID users. This task requires a complex interface of setting the positions and the parameters of camera and lights for optimal rendering results. However, the user interface of existing CAID tools are not simple for designers because the task is mostly accomplished in a parameter setting dialogue window. This research address this interface issues, in particular the issues related to lighting, by developing and evaluating TLS(Tangible Lighting Studio) that uses Augmented Reality and Tangible User Interface. The interface of positioning objects and setting parameters become tangible and distributed in the workspace to support more intuitive rendering task. TLS consists of markers, and physical controller, and a see-through HMD(Head Mounted Display). The user can directly control the lighting parameters in the AR workspace. In the evaluation experiment, TLS provide higher effectiveness, efficiency and user satisfaction compared to existing GUI(Graphic User Interface) method. It is expected that the application of TLS can be expanded to photography education and architecture simulation.