• Title/Summary/Keyword: 환기전략

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Analysis of Greenhouse Thermal Environment by Model Simulation (시뮬레이션 모형에 의한 온실의 열환경 분석)

  • 서원명;윤용철
    • Journal of Bio-Environment Control
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    • v.5 no.2
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    • pp.215-235
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    • 1996
  • The thermal analysis by mathematical model simulation makes it possible to reasonably predict heating and/or cooling requirements of certain greenhouses located under various geographical and climatic environment. It is another advantages of model simulation technique to be able to make it possible to select appropriate heating system, to set up energy utilization strategy, to schedule seasonal crop pattern, as well as to determine new greenhouse ranges. In this study, the control pattern for greenhouse microclimate is categorized as cooling and heating. Dynamic model was adopted to simulate heating requirements and/or energy conservation effectiveness such as energy saving by night-time thermal curtain, estimation of Heating Degree-Hours(HDH), long time prediction of greenhouse thermal behavior, etc. On the other hand, the cooling effects of ventilation, shading, and pad ||||&|||| fan system were partly analyzed by static model. By the experimental work with small size model greenhouse of 1.2m$\times$2.4m, it was found that cooling the greenhouse by spraying cold water directly on greenhouse cover surface or by recirculating cold water through heat exchangers would be effective in greenhouse summer cooling. The mathematical model developed for greenhouse model simulation is highly applicable because it can reflects various climatic factors like temperature, humidity, beam and diffuse solar radiation, wind velocity, etc. This model was closely verified by various weather data obtained through long period greenhouse experiment. Most of the materials relating with greenhouse heating or cooling components were obtained from model greenhouse simulated mathematically by using typical year(1987) data of Jinju Gyeongnam. But some of the materials relating with greenhouse cooling was obtained by performing model experiments which include analyzing cooling effect of water sprayed directly on greenhouse roof surface. The results are summarized as follows : 1. The heating requirements of model greenhouse were highly related with the minimum temperature set for given greenhouse. The setting temperature at night-time is much more influential on heating energy requirement than that at day-time. Therefore It is highly recommended that night- time setting temperature should be carefully determined and controlled. 2. The HDH data obtained by conventional method were estimated on the basis of considerably long term average weather temperature together with the standard base temperature(usually 18.3$^{\circ}C$). This kind of data can merely be used as a relative comparison criteria about heating load, but is not applicable in the calculation of greenhouse heating requirements because of the limited consideration of climatic factors and inappropriate base temperature. By comparing the HDM data with the results of simulation, it is found that the heating system design by HDH data will probably overshoot the actual heating requirement. 3. The energy saving effect of night-time thermal curtain as well as estimated heating requirement is found to be sensitively related with weather condition: Thermal curtain adopted for simulation showed high effectiveness in energy saving which amounts to more than 50% of annual heating requirement. 4. The ventilation performances doting warm seasons are mainly influenced by air exchange rate even though there are some variations depending on greenhouse structural difference, weather and cropping conditions. For air exchanges above 1 volume per minute, the reduction rate of temperature rise on both types of considered greenhouse becomes modest with the additional increase of ventilation capacity. Therefore the desirable ventilation capacity is assumed to be 1 air change per minute, which is the recommended ventilation rate in common greenhouse. 5. In glass covered greenhouse with full production, under clear weather of 50% RH, and continuous 1 air change per minute, the temperature drop in 50% shaded greenhouse and pad & fan systemed greenhouse is 2.6$^{\circ}C$ and.6.1$^{\circ}C$ respectively. The temperature in control greenhouse under continuous air change at this time was 36.6$^{\circ}C$ which was 5.3$^{\circ}C$ above ambient temperature. As a result the greenhouse temperature can be maintained 3$^{\circ}C$ below ambient temperature. But when RH is 80%, it was impossible to drop greenhouse temperature below ambient temperature because possible temperature reduction by pad ||||&|||| fan system at this time is not more than 2.4$^{\circ}C$. 6. During 3 months of hot summer season if the greenhouse is assumed to be cooled only when greenhouse temperature rise above 27$^{\circ}C$, the relationship between RH of ambient air and greenhouse temperature drop($\Delta$T) was formulated as follows : $\Delta$T= -0.077RH+7.7 7. Time dependent cooling effects performed by operation of each or combination of ventilation, 50% shading, pad & fan of 80% efficiency, were continuously predicted for one typical summer day long. When the greenhouse was cooled only by 1 air change per minute, greenhouse air temperature was 5$^{\circ}C$ above outdoor temperature. Either method alone can not drop greenhouse air temperature below outdoor temperature even under the fully cropped situations. But when both systems were operated together, greenhouse air temperature can be controlled to about 2.0-2.3$^{\circ}C$ below ambient temperature. 8. When the cool water of 6.5-8.5$^{\circ}C$ was sprayed on greenhouse roof surface with the water flow rate of 1.3 liter/min per unit greenhouse floor area, greenhouse air temperature could be dropped down to 16.5-18.$0^{\circ}C$, whlch is about 1$0^{\circ}C$ below the ambient temperature of 26.5-28.$0^{\circ}C$ at that time. The most important thing in cooling greenhouse air effectively with water spray may be obtaining plenty of cool water source like ground water itself or cold water produced by heat-pump. Future work is focused on not only analyzing the feasibility of heat pump operation but also finding the relationships between greenhouse air temperature(T$_{g}$ ), spraying water temperature(T$_{w}$ ), water flow rate(Q), and ambient temperature(T$_{o}$).

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The Effect and Safety of Alveolar Recruitment Maneuver using Pressure-Controlled Ventilation in Acute Lung Injury and Acute Respiratory Distress Syndrome (급성폐손상과 급성호흡곤란증후군 환자에서 압력조절환기법을 이용한 폐포모집술의 효과와 안정성)

  • Chung, Kyung Soo;Park, Byung Hoon;Shin, Sang Yun;Jeon, Han Ho;Park, Seon Cheol;Kang, Shin Myung;Park, Moo Suk;Han, Chang Hoon;Kim, Chong Ju;Lee, Sun Min;Kim, Se Kyu;Chang, Joon;Kim, Sung Kyu;Kim, Young Sam
    • Tuberculosis and Respiratory Diseases
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    • v.63 no.5
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    • pp.423-429
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    • 2007
  • Background: Alveolar recruitment (RM) is one of the primary goals of respiratory care for an acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). The purposes of alveolar recruitment are an improvement in pulmonary gas exchange and the protection of atelectrauma. This study examined the effect and safety of the alveolar RM using pressure control ventilation (PCV) in early ALI and ARDS patients. Methods: Sixteen patients with early ALI and ARDS who underwent alveolar RM using PCV were enrolled in this study. The patients data were recorded at the baseline, and 20 minutes, and 60 minutes after alveolar RM, and on the next day after the maneuver. Alveolar RM was performed with an inspiratory pressure of $30cmH_2O$ and a PEEP of $20cmH_2O$ in a 2-minute PCV mode. The venous $O_2$ saturation, central venous pressure, blood pressure, pulse rate, $PaO_2/FiO_2$ ratio, PEEP, and chest X-ray findings were obtained before and after alveolar RM. Results: Of the 16 patients, 3 had extra-pulmonary ALI/ARDS and the remaining 13 had pulmonary ALI/ARDS. The mean PEEP was 11.3 mmHg, and the mean $PaO_2/FiO_2$ ratio was 130.3 before RM. The $PaO_2/FiO_2$ ratio increased by 45% after alveolar RM. The $PaO_2/FiO_2$ ratio reached a peak 60 minutes after alveolar RM. The Pa$CO_2$ increased by 51.9 mmHg after alveolar RM. The mean blood pressure was not affected by alveolar RM. There were no complications due to pressure injuries such as a pneumothorax, pneumomediastinum, and subcutaneous emphysema. Conclusion: In this study, alveolar RM using PCV improved the level of oxygenation in patients with an acute lung injury and acute respiratory distress syndrome. Moreover, there were no significant complications due to hemodynamic changes and pressure injuries. Therefore, alveolar RM using PCV can be applied easily and safely in clinical practice with lung protective strategy in early ALI and ARDS patients.

The Effect of Curiosity and Need for Uniqueness on Emotional Responses to Art Collaborated Products including Moderating Effect of Gender (독특성 추구성향과 호기심이 아트 콜라보레이션 제품에 대한 소비자의 감정에 미치는 영향: 성별에 따른 조절효과)

  • Ju, Seon Hee;Koo, Dong-Mo
    • Asia Marketing Journal
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    • v.14 no.2
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    • pp.97-125
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    • 2012
  • Companies recently introduce art collaborated products incorporating culture into a product. Art collaborated products include incorporating famous movies and/or design of an artist into a newly launched product. The introduction of art collaborated products are gradually increasing. However, research for this trend is relatively scarce. Although research concerning design has discussed a number of different factors as playing a role in influencing responses to design including culture, fashion, innate preferences, etc.), only limited attention has been paid to the processes by which consumers generate responses to product designs. People with different characteristics may respond differently. When people encounter these art products, they may become curious, may think that these products are unique, novel and innovative. People tend to show different levels of curiosity when they encounter new and novel objects, which they have rarely seen or experienced. Curiosity is defined as a desire for acquiring new knowledge and new sensory experience. Previous studies demonstrated that curiosity motivates individuals to engage in exploratory behaviors. People also show different levels of need for uniqueness, which is defined as being different from others or becoming distinctive among a larger group. Individual's need for uniqueness results from signals conveyed by the material objects that individuals choose to display. Recently, researcher have developed the need for uniqueness with three distinct constructs. These three concepts include creative choice, unpopular choice, and avoidance of similarity. Creative choice is a trait tendency of an individual by expressing or differentiating himself from others through consumptions of unique products. Unpopular choice is related to an individual's tendency to consume products, which deviates from group norms. Avoidance of similarity is linked to the avoidance of consumption behavior of products that are not famous. Past research implies that people with different levels of need for uniqueness show different motivational processes. Previous research also demonstrates that different customer emotions may be derived when consumers are exposed to these art collaborated products. Research tradition has been investigated three different emotional responses such as pleasure, arousal, and dominance. Pleasure is defined as the degree to which a person feels good, joyful, happy, or satisfied in a situation. Arousal is defined as the extent to which a person feels stimulated, active, or excited. Dominance is defined as the extent that a person feels powerful vis-a-vis the environment that surrounds him/her. Previous research show that complex, speedy, and surprising stimuli may excite consumers and thus make them more pleased and engaged in their approach behavior. However, the current study identified these emotional responses as positive emotion, negative emotion, and arousal. These derived emotions may lead consumers to approach and/or avoidance behaviors. In addition, males and females tend to respond differently when they are exposed to art collaboration products. Building on this research tradition, the current study aims to investigate the inter-relationships between individual traits such as curiosity and need for uniqueness and individual's emotional responses including positive and negative emotion and arousal when people encounter various art collaborated products. Emotional responses are proposed to influence purchase intention. Additionally, previous studies show that male and females respond differently to similar stimuli. Accordingly, gender difference are proposed to moderate the links between individual traits and emotional responses. These research aims of the current study may contribute to extending our knowledge in terms of (1) which individual characteristics are related to different emotions, and (2) how these different emotional responses inter-connected to future purchase intention of arts collaborated products. In addition, (3) the different responses to these arts collaborated products by males and females will guide managers how to concoct different strategies to these segments. The questionnaire for the present study was adopted from the previous literature and validated with a pilot test. The survey was conducted in Daegu, a third largest city in South Korea, for three weeks during June and July 2011. Most respondents were in their twenties and thirties. 350 questionnaires were distributed and among them 300 were proved to be valid (valid response rate of 85.7%). Survey questionnaires from valid 300 respondents are used to test hypotheses proposed. The structural equation model (SEM) was used to validate the research model. The measurement and structural model was tested using LISREL 8.7. The measurement model test demonstrated that consistency, convergent validity, and discriminat validity of the measurement items were acceptable. The results from the structural model demonstrate that curiosity has a positive impact on positive emotion, but not on negative emotion and arousal. Need for uniqueness has three different sub-concepts such as creative choice, unpopular choice, and avoidance of similarity. The results show that creative choice has a positive effect on arousal and positive emotion, but has a negative impact on negative emotion. Unpopular choice has a positive effect on arousal, but on neither positive nor negative emotions. Avoidance of similarity has no impact on neither emotions nor arousal. The results also demonstrated that gender has a moderating influence. Males show more negative emotion to creative and unpopular choices. Implications and future research directions are discussed in conclusion.

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Comparison of Two Methods of Recruiting the Acutely Injured Lung (급성 폐손상에서 폐를 Recruit시키는 방법간의 비교 연구)

  • Suh, Gee-Young;Kang, Kyeong-Woo;Park, Sang-Joon;Kim, Ho-Choel;Young, Lim-Si;Chung, Man-Pyo;Han, Jeong-Ho;Kim, Ho-Joong;Kwon, O-Jung;Rhee, Chong-H.
    • Tuberculosis and Respiratory Diseases
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    • v.48 no.4
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    • pp.500-512
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    • 2000
  • Background : To evaluate the efficacy of two methods of obtaining lung recruitment to reduce ventilator-induced lung injury(VILI). Methods : Fifteen New-Zealand white rabbits were ventilated in the pressure-controlled mode while maintaining constant tidal volume(10 ml/kg) and fixed respiration rate. Lung injury was induced by repeated saline lavage (PaO2<100 mmHg), and the pressure-volume curve was drawn to obtain Pflex. The animals were then randomly assigned to three groups and ventilated for 4 hours. In the control group(n=5), positive end-expiratory pressure(PEEP) less than that of Pflex by 3 mmHg was applied throughout the study. In the recruitment maneuver(RM) group(n=5), RM(CPAP of 22.5 mmHg, for 45 seconds) was performed every 15 minutes in addition to PEEP level less than Pflex by 3 mmHg This phrase is unclear. In the Pflex group, PEEP of Pflex was given without RM. Gas exchange, lung mechanics, and hemodynamics parameters as well as pathology were examined. Results : 1) Both the control and RM groups showed decreasing tendency in PaO2 with time. There was significantly decreased PaO2 at 4 hr compared to Ihr(p<0.05). But in the Pflex group, PaO2 did not decrease with time(p<0.05 vs other groups at 3, 4 hr). PaCO2 did not show significant difference among the three groups. 2) There was no significant difference in static compliance and plateau pressure. Mean blood pressure and heart rate also did not show any significant difference among the three groups. 3) The pathologic exam showed significantly less neutrophil infiltration in the Pflex group than in the control group(p<0.05). There was borderline significant difference in hyaline membrane score among the groups (p= 0.0532). Conclusion : Although recruitment maneuver of the injured lung may be important in decreasing VILI, it alone may not be sufficient to minimize VILI.

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A System Simulation Model of Proton Exchange Membrane Fuel Cell for Residential Power Generation for Thermal Management Study (가정용 연료전지 시스템의 열관리 해석을 위한 시스템 운전 모델 개발)

  • Yu, Sang-Seok;Lee, Young-Duk;Ahn, Kook-Young
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.34 no.1
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    • pp.19-26
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    • 2010
  • A PEMFC(proton exchange membrane fuel cell) is a good candidate for residential power generation to be coped with the shortage of fossil fuel and green house gas emission. The attractive benefit of the PEMFC is to produce electric power as well as hot water for home usage. The thermal management of PEMFC for RPG is to utilize the heat of PEMFC so that the PEMFC can be operated at its optimal efficiency. In this study, thermal management system of PEMFC stack is modeled to understand the dynamic response during load change. The thermal management system of PEMFC for RPGFC is composed of two cooling circuits, one for controling the fuel cell temperature and the other for heating up the water for home usage. The different operating strategy is applied for each cooling circuit considering the duty of those two circuits. Even though the capacity of PEMFC system (1kW) is enough to supply hot domestic water for residence, heat-up of reservior takes some hours. Therefore, in this study, time schedule of the simulation reflects the heat-up process. Dynamic responses and operating strategies of the PEMFC system are investigated during load changes.

The narrative features of as seen through digital culture (<이제부터 제리타임 It's Jerry Time!>을 통해 본 디지털 문화 속 웹 애니메이션의 서사적 특징)

  • Kim, YoungOk
    • Cartoon and Animation Studies
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    • s.34
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    • pp.23-43
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    • 2014
  • The development of the Internet in the 21st century had made a variety of cross-cultural environment so that animations also have evolved with new features to Web-Animation. In Korea, the web-based flash animation leap forward to the animation Utopia in the early 2000's, but did not last long. The web-based animations should attract audience's attention not only with it's minimum streaming capacity but also with showing it's best qualities as well, Therefore, the stimulating narrative strategies were mandatories for web-animation in 2000's. The absence of in-depth research on media, poor revenue structure, and the emergence of mobile games and e-learning industries made the web-animation become just a one-time/one-consumable content. There were no subsequent generation of korean web-animation ever since. In this study, I want to introduce and analyze the american web animation series, (2005) as a new type of web-animation in current digital culture, In particular, I want to discuss how this web animation appeal to the audience with its narrative strategies through using some aspect of the internet culture which's differentiated from traditional media based cultures. This research could suggest diverse narrative strategies for the future web-animation with new vision. Moreover, This also allows to look at latest web-animation trends and its new experiments.

A Study on the First Person Narrator in Animation : Focusing on the narration of childhood experience as retrospection (애니메이션의 일인칭 서술자 연구 : 회상으로서의 유년 체험 서술을 중심으로)

  • Cho, Mi-Ra
    • Cartoon and Animation Studies
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    • s.22
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    • pp.31-45
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    • 2011
  • The paper holds its purpose to analyze the descriptive function and meaning of first person animation which the focalizer, character, and all narrators are indicated as 'I', For the purpose, the following was reviewed; the relation between 'I' as child memorizing the days of childhood as adult and the current 'I' as adult, and the aesthetic effect of experience and sense of the child on the audience reading the narration. The retrospective narrating situation of the adult narrator brings descriptive effect which comes from 'the tension between the experiencing self (self as child) and the narrative self (self as adult). The works focus on the content of child experience through the confession of the adult narrator, but the view of the adult always heading towards 'the present'. That is, the aesthetics contained by the first person narrator is related to endless arousal of the values of hidden and forgotten things. In addition, the descriptive method of child focalizer as 'the subject of experience' brings qualitative change which enables reasoning of the subject as itself, which is free from the view tamed by rational system. Becoming an adult, the lost ability of mimesis brings qualitative change by meeting with the generality of childhood sense. Therefore, it can be known that the meaning the narrator contains in the first person narrator condition of animation links with the degree of aesthetic completion of the work, but also, it is a highly strategic descriptive device which determinately affects even the acceptance of audiences regarding the work.

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Development of EPC Business Process Management Model for Improving Plant Project Management (플랜트프로젝트 사업관리 업무절차 개선을 위한 EPC 수행단계별 BPM모델 개발)

  • Park, Bum-Jin;Lee, Min-Jae;Lee, Tai-Sik
    • Korean Journal of Construction Engineering and Management
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    • v.9 no.5
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    • pp.149-158
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    • 2008
  • Plant construction is being a motive power of national economic growth, because it is a higher value-added business which has enormous influence through other industry. But, plant projects management of the domestic company was poor. So, the development of EPC Business Process Management method has been encouraged. Therefore, this paper performed several researches for setting up the EPC Business Process Management Model for improving plant project management. And the details are as follows. First of all, this study collected the work procedure manuals of 12 large-sized international construction companies. Secondly, from the analyzing gathered EPC work procedure manuals, issues of work procedure manuals were analyzed and improvement plans were drawn out. Basis on this, This study presents a method to improve project management for EPC plant project. 'The Work Procedure Matrix for EPC Management' and 'Key Unit Works for EPC Management' were drawn out by using overseas construction management theories and international regulations. In addition, 'The EPC Business Process Management Models' reformed to the Business process method, that is the set of specifications, documents and procedures used to manage the EPC plant project. And it describes how the EPC work procedure manuals will be used. Finally, this study suggests the model of EPC Business Process Management System. The framework of Plant project management can be clarified by using 'The Work Procedure Matrix'. And 'Key Unit Works' are used to organize the work procedure needed to improve plant projects management. The results of this study will help to improve in project management efficiency for plant construction.

Analysis on Factors Influencing Foreign Chinese Students' Off-Campus Restaurant Satisfaction (중국인 유학생의 외식 만족도에 영향을 주는 요인 분석)

  • Bae, Hyun-Joo;Boo, Goun
    • Korean journal of food and cookery science
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    • v.31 no.6
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    • pp.749-755
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    • 2015
  • The objectives of this study were to evaluate the gap between perceived importance and performance of foreign Chinese students' off-campus restaurants selection attributes and to analyze the factors affecting their satisfaction with off-campus restaurants. All statistical analyses were conducted using the SPSS package program (ver. 20.0). In summary, Importance-Performance Analysis results indicated that 'price propriety', 'ventilation of dining room' and 'friendliness of employees' were key aspects that should be reinforced by off-campus restaurant managers. Additionally, exploratory factor analysis on the validity of the 23 attributes of off-campus restaurant selection resulted in the identification of 5 factors including 'food quality and price', 'physical environment and value', 'service environment', 'service quality', and 'convenience and cleanness'. According to the results of multiple regression analysis, 'service quality', 'service environment', 'food quality and price', and 'physical environment and value' had significantly positive effects on overall satisfaction. In conclusion, in order to increase customer satisfaction among Chinese students, off-campus restaurant managers should improve not only the quality of service and food, but also the physical and service environment.

Environmental monitoring system research based on low-power sensor network (저전력 센서네트워크 기반 환경모니터링 시스템 연구)

  • Kim, Ki-Tae;Kim, Dong-Il
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2011.10a
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    • pp.807-810
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    • 2011
  • The sensor network technology for core technology of ubiquitous computing is in the spotlight recently, the research on sensor network is proceeding actively which is composed many different sensor node. USN(Ubiquitous Sensor Network) is the network that widely applies for life of human being. It works out to sense, storage, process, deliver every kind of appliances and environmental information from the stucktags and sensors. And it is possible to utilize to measure and monitor about the place of environmental pollution which is difficult for human to install. It's studied constantly since it be able to compose easily more subminiature, low-power, low-cost than previous one. And also it spotlights an important field of study, graft the green IT and IT of which the environment and IT unite stragically onto the Network. The problem for the air pollution in the office or the indoor except a specific working area is the continuously issue since the human beings have lived in the dwelling facilities. Measures for that problem are urgently needed. It's possible to solve for the freshair of outside with enough ventilation but that is the awkward situation to be managed by person. This study is the system engineering to management for indoor air condition under the sensor network. And research for efficiently manage an option.

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