• 제목/요약/키워드: External events

검색결과 229건 처리시간 0.02초

Vibratory loads and response prediction for a high-speed flight vehicle during launch events

  • Kim, Jinhyeong;Park, Seoryong;Eun, Wonjong;Shin, Sangjoon;Lee, Soogab
    • International Journal of Aeronautical and Space Sciences
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    • 제17권4호
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    • pp.551-564
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    • 2016
  • High-speed flight vehicles (HSFVs) such as space launch vehicles and missiles undergo severe dynamic loads which are generated during the launch and in in-flight environments. A typical vehicle is composed of thin plate skin structures with high-performance electronic units sensitive to such vibratory loads. Such lightweight structures are then exposed to external dynamic loads which consist of random vibration, shock, and acoustic loads created under the operating environment. Three types of dynamic loads (acoustic loads, rocket motor self-induced excitation loads and aerodynamic fluctuating pressure loads) are considered as major components in this study. The estimation results are compared to the design specification (MIL-STD-810) to check the appropriateness. The objective of this paper is to study an estimation methodology which helps to establish design specification for the dynamic loads acting on both vehicle and electronic units at arbitrary locations inside the vehicle.

Risk Assessment from Heterogeneous Energy Deposition in Tissue. The Problem of Effects from Low Doses of Ionizing Radiation

  • Le, Feinendegen;J, Booz
    • 대한핵의학회지
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    • 제26권1호
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    • pp.8-13
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    • 1992
  • Low doses of ionizing radiation from external or internal sources cause heterogeneous distribution of energy deposition events in the exposed biological system. With the cell being the individual element of the tissue system, the fraction of cells hit, the dose received by the hit, and the biological response of the cell to the dose received eventually determine the effect in tissue. The hit cell may experience detriment, such as change in its DNA leading to a malignant transformation, or it may derive benefit in terms of an adaptive response such as a temporary improvement of DNA repair or temporary prevention of effects from intracellular radicals through enhanced radical detoxification. These responses are protective also to toxic substances that are generated during normal metabolism. Within a multicellular system, the probability of detriment must be weighed against the probability of benefit through adaptive responses with protection against various toxic agents including those produced by normal metabolism. Because irradiation can principally induce both, detriment and adaptive responses, one type of affected cells may not be simply summed up at the expense of cells with other types of effects, in assessing risk to tissue. An inventory of various types of effects in the blood forming system of mammals, even with large ranges of uncertainty, uncovers the possibility of benefit to the system from exposure to low doses of low LET radiation. This experimental approach may complement epidemiological data on individuals exposed to low doses of ionizing radiation and may lead to a more rational appraisal of risk.

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공항운영인력의 ASQ 서비스성과 공유에 대한 인식 및 귀인 연구 : 인천공항 아웃소싱직원을 중심으로 (A Study of Incheon Airport Employees' Perception and Attribution on ASQ Service Performances focusing on Outsource Workers)

  • 송정태;김기웅;최연철;박성식
    • 한국항공운항학회지
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    • 제24권1호
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    • pp.62-70
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    • 2016
  • Perception of outsource workers among Incheon Int'l airport employees was reviewed about the service performances of winning the ASQ awards in 11 consecutive years. 85% of Incheon airport operating authority(Incheon International Airport Corp.) and its outsource companies employees was composed of outsource workers. Thus, their thoughts might represent the overall perception of airport operating authority employees. The perception on the service performances of winning the ASQ awards was analyzed by researchers using attribution theory model. It is useful to apply attribution modeling in order to analyze the causal relationships among variables. Attribution is the process by which individuals explain the causes of behavior and events. Attribution theory is the study of models to explain those processes. According to empirical analysis, it was found outsource workers attributed the excellent service performance of Incheon airport to such an internal factor as service competence. However it was also implied they attributed to such external factors as the positive relationship and institutional support from airport and government authorities.

The structural safety assessment of a tie-down system on a tension leg platform during hurricane events

  • Yang, Chan K.;Kim, M.H.
    • Ocean Systems Engineering
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    • 제1권4호
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    • pp.263-283
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    • 2011
  • The performance of a rig tie-down system on a TLP (Tension Leg Platform) is investigated for 10-year, 100-year, and 1000-year hurricane environments. The inertia loading on the derrick is obtained from the three-hour time histories of the platform motions and accelerations, and the dynamic wind forces as well as the time-dependent heel-induced gravitational forces are also applied. Then, the connection loads between the derrick and its substructure as well as the substructure and deck are obtained to assess the safety of the tie-down system. Both linear and nonlinear inertia loads on the derrick are included. The resultant external forces are subsequently used to calculate the loads on the tie-down clamps at every time step with the assumption of rigid derrick. The exact dynamic equations including nonlinear terms are used with all the linear and second-order wave forces considering that some dynamic contributions, such as rotational inertia, centripetal forces, and the nonlinear excitations, have not been accounted for in the conventional engineering practices. From the numerical simulations, it is seen that the contributions of the second-order sum-frequency (or springing) accelerations can be appreciable in certain hurricane conditions. Finally, the maximum reaction loads on the clamps are obtained and used to check the possibility of slip, shear, and tensile failure of the tie-down system for any given environment.

Linking Clinical Events in Elderly to In-home Monitoring Sensor Data: A Brief Review and a Pilot Study on Predicting Pulse Pressure

  • Popescu, Mihail;Florea, Elena
    • Journal of Computing Science and Engineering
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    • 제2권2호
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    • pp.180-199
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    • 2008
  • Technology has had a tremendous impact on our daily lives. Recently, technology and its impact on aging has become an expanding field of inquiry. A major reason for this interest is that the use of technology can help older people who experience deteriorating health to live independently. In this paper we give a brief review of the in-home monitoring technologies for the elderly. In the pilot study, we analyze the possibility of employing the data generated by a continuous, unobtrusive nursing home monitoring system for predicting elevated(abnormal)pulse pressure(PP) in elderly(PP=systolic blood pressure-diastolic blood pressure). Our sensor data capture external information(behavioral) about the resident that is subsequently reflected in the predicted PP. By continuously predicting the possibility of elevated pulse pressure we may alert the nursing staff when some predefined threshold is exceeded. This approach may provide additional blood pressure monitoring for the elderly persons susceptible to blood pressure variations during the time between two nursing visits. We conducted a retrospective pilot study on two residents of the TigerPlace aging in place facility with age over 70, that had blood pressure measured between 100 and 300 times during a period of two years. The pilot study suggested that abnormal pulse pressure can be reasonably well estimated (an area under ROC curve of about 0.75) using apartment bed and motion sensors.

A mathematical spatial interpolation method for the estimation of convective rainfall distribution over small watersheds

  • Zhang, Shengtang;Zhang, Jingzhou;Liu, Yin;Liu, Yuanchen
    • Environmental Engineering Research
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    • 제21권3호
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    • pp.226-232
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    • 2016
  • Rainfall is one of crucial factors that impact on our environment. Rainfall data is important in water resources management, flood forecasting, and designing hydraulic structures. However, it is not available in some rural watersheds without rain gauges. Thus, effective ways of interpolating the available records are needed. Despite many widely used spatial interpolation methods, few studies have investigated rainfall center characteristics. Based on the theory that the spatial distribution of convective rainfall event has a definite center with maximum rainfall, we present a mathematical interpolation method to estimate convective rainfall distribution and indicate the rainfall center location and the center rainfall volume. We apply the method to estimate three convective rainfall events in Santa Catalina Island where reliable hydrological data is available. A cross-validation technique is used to evaluate the method. The result shows that the method will suffer from high relative error in two situations: 1) when estimating the minimum rainfall and 2) when estimating an external site. For all other situations, the method's performance is reasonable and acceptable. Since the method is based on a continuous function, it can provide distributed rainfall data for distributed hydrological model sand indicate statistical characteristics of given areas via mathematical calculation.

고등학생들의 성별 조절점 방향 실태 및 환경 행동과의 관련성 조사 (Orientation of Locus of Control and Environmental Behavior in High School Students)

  • 박진희;장남기
    • 한국환경교육학회지:환경교육
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    • 제9권1호
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    • pp.17-29
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    • 1996
  • 'Control of Locus of Reinforcement(LOCR)' is considered one of the main important factors on responsible environmental behaviors(REB). It is defined as 'an individual's perception of his or her ability to bring about change through his or her behavior'. This phychological construct is divided in two, external locus and internal locus. Internal locus of reinforcement is important as predictor for REB. Lately, 'The Environmental Action Internal Control Index:EAICI' was developed. It is a valid and reliable instrument to measure relationships of two variables. The purposes of this study were to analyse the orientation of LOCR in high school students and relations with LOCR to REB. By the results, EAICI scores of total students, males, females are 99.83, 95.10, 104.56, respectively. LOCR of females was stronger and more internal than one of males. The item scores for behaviors that reduce the amount of household trash by reusing and recycling and convince someone to do this are 4.31, 4.05, respectively. The item scores for behaviors that convince someone to sign a petition regarding on environmental issues, convince someone to reuse envelopes by putting a label over the old address and convince someone to keep car tires properly inflated are 3.09, 3.09, 3.04, respectively. It shows that EAICI scores are dependent upon the degree of the chances and experiences to meet the various environmental events.

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방사선 사고와 급성 방사선 증후군 (Radiological Accident and Acute Radiation Syndrome)

  • 노형근
    • 대한임상독성학회지
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    • 제9권2호
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    • pp.39-48
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    • 2011
  • In mass casualty situation due to radiological accidents, it is important to start aggressive management with rapid triage decisions. External contamination needs immediate decontamination and internal contamination should be treated with special expertise and equipment to prevent the rapid uptake of radionuclides by target organs. Acute radiation syndrome shows a sequence of events that varies with the severity of the exposure. More severe exposures generally lead to more rapid onset of symptoms and severe clinical findings. After the massive exposure, various systems of the body reflect their severe damages that can lead to death within hours or up to several months. The disease progression has classically been divided into four stages: prodromal, latent, manifest illness, and recovery or death. Three characteristic clusters of symptoms including the hematopoietic syndrome, the gastrointestinal syndrome and the cerebrovascular syndrome are all associated with the acute radiation syndrome. The standard medical management of the patients with a potentially survivable radiation exposure includes good medical, surgical and supportive measures. Specific treatment with cytokines and bone marrow transplantation should be considered. The management of internal contamination is much the same as the treatment of poisoning. The standard decontamination should be applied to reduce uptake, and the chelating agents can be administered to enhance the clearance of radioisotopes. Radioactive iodine ($^{131}I$) as one of the nuclear fission products can increase the incidence of thyroid cancer in children. Potential benefit of potassium iodide prophylaxis is greater especially in neonates, infants and small children.

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Intelligent Digital Public Address System using Agent Based on Network

  • 김정숙
    • 한국지능시스템학회논문지
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    • 제23권1호
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    • pp.87-92
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    • 2013
  • In this paper, we developed a digital and integrated PA(Public Address) system with speech recognition and sensor connection based on IP with an ID using agent. It has facilities such as an external input, a microphone and a radio for a PA system and has speech recognition. If "fire" is spoken to the PA system then it can recognize the emergency situation and will broadcast information to the appropriate agency immediately. In addition to that, many sensors, such as temperature, humidity, and infrared, etc., can be connected to the PA system and can be integrated with the context awareness which contains many types of information about internal statuses using inference agent. Also, developed the digital integrated PA system will make it possible to broadcast the message to adaptable places using network IP based on IDs. Finally, the digital PA system is designed for operation from a PC, which makes installation and setting of operating parameters very simple and user-friendly. For implementation details, we implemented thread based concurrent processing for the events which occur concurrently from many sensors or users.

A Study on the Features of the Modernization Process in the Chinese Costume

  • Kim, Eun-Jung;Kang, Soon-Che
    • International Journal of Costume and Fashion
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    • 제9권1호
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    • pp.1-14
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    • 2009
  • This study is intended to examine the modernization of Chinese costumes through historical events, and to analyze the characteristics of the costume modernization process. The modernization of Chinese costumes appears to have begun with the Opium Wars, and the Nanjing Treaty(1842), the Beijing Treaty(1860) and the official residence of western people in Chinese territory. Afterwards, in order to initiate change, the Chinese people themselves implemented the Westernization movement(1861-94), placing an emphasis on the westernization of external elements such as technology and form, but aspects such as costume, deeply saturated in their traditions, do not appear to have changed significantly. Despite self-empowering movements such as these, as western forces diffused deeper into the Chinese mainland, neo-intellectuals formed the axis of a revolutionary movement. A major example can be found in the Xinhai Revolution(1911) revolution, which forbade the binding of feet and shaving of frontal hair and partially implemented western formal dress. Through these factors, the modernization process of Chinese costume demonstrates characteristics of an adherence to traditional dress and partial acceptance of western attire. Through this, we may understand the modern costumes of China, which adhered more to tradition than Japan, which pursued western costumes actively within a similar period, and Korea, which rushed modernization due to Japanese authority.