• Title/Summary/Keyword: Design (control) factors

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Limitation of Prediction on Intravenous Immunoglobulin Responsiveness in Kawasaki Disease (가와사끼병에서 정맥용 면역글로불린 치료 반응 예측의 한계)

  • Kim, Seong-Koo;Han, Ji-Yoon;Rhim, Jung Woo;Oh, Jin Hee;Han, Ji-Whan;Lee, Kyung Yil;Kang, Jin-Han;Lee, Joon-Sung
    • Pediatric Infection and Vaccine
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    • v.17 no.2
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    • pp.169-176
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    • 2010
  • Purpose : We aimed to evaluate predictive parameters for non-response to intravenous immunoglobulin (IVIG) in patients with Kawasaki disease (KD) before IVIG use using two controls. Methods : We evaluated 229 consecutive KD patients who were treated with 2 g/kg of IVIG at a single center. Those who had persistent fever >24 hours after IVIG infusion made up the 23 IVIG non-responders; the first control included a total 206 defervesced cases and the second control included 46 cases that were matched for age and pre-treatment fever duration to non-responders. Results : Demographic and clinical characteristics were similar in IVIG non-responders and responders at presentation. As for laboratory findings, the neutrophil differential, CRP, AST, ALT, and LDH were higher, and lymphocyte differential, total protein, albumin, platelet count, and total cholesterol were significantly lower in IVIG non-responders compared to responders by univariate analysis in both study designs. However in multivariate analysis, non-responders showed a significantly higher neutrophil differential (cutoff value, >77%, sensitivity 68.4% and specificity 79.5%) and lower cholesterol (<124 mg/dL, sensitivity 79% and specificity 70.5%). Whereas plasma albumin (<3.6 g/dL, sensitivity 73.7% and specificity 60%) was the sole laboratory parameter of non-responders in the second study design. Conclusion : Severity of inflammation in KD was reflected by higher or lower laboratory values at presentation. Because the multivariate analysis for these indices may be influenced by some confounding factors, including the numbers of patients of different ages and fever duration, other assessment modalities are needed for KD patients with the greatest risk of coronary artery lesions.

Effects of Educational Programs Utilizing Forests on Maladjusted Behavior of Mentally Retarded Students (숲을 활용한 교육이 정신지체학생의 부적응행동에 미치는 영향)

  • Park, Kyoung-Lee;Sim, Woo-Kyung
    • Journal of the Korean Institute of Landscape Architecture
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    • v.38 no.5
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    • pp.64-79
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    • 2010
  • Students with intellectual disabilities typically have great difficulties communicating their needs and wants and may get frustrated, anxious or show signs of aggressive behaviour. They are often unable to understand the concept of relationships with other people as well. This lack of social communication and interaction leads to poor motivation which increases other areas of difficulty in their lives. Therefore, to teach students with intellectual disabilities, it is essential to find special teaching methods to support their positive behavior. This paper proposes that special educational curriculum for students with intellectual impairments utilize natural environments(forests) and materials. The purpose of this study was to investigate the effects of Educational Programs Utilizing Forests on maladjusted behavior of students with mental retardation and to examine the positive effects of such planning practices. The subjects were middle school students who attended a special school for mentally-retarded students. They were divided into two separate groups- an experimental group and a control group. All subjects received the pre and post test using the same method. This program was applied to the formal educational process of middle school from March 1st to October 30th, 2009. In this experiment the results indicate that the effect of using a natural environment(forest) and the materials within a formal educational curriculum was positive as a type of horticultural therapy and that it supports positive behavior strategies in students with intellectual impairments. The usage of various natural materials including plants and flowers within the natural environments provide students with increased opportunities to participate. Teaching methods including natural materials help teachers engage with their students more easily during routine activities as their interest is already stimulated. This project will help students with intellectual impairments to build skills which enable effective participation and increase independence throughout their lives. This should be embedded into both routine and planned activities of the classroom Also, it offers a needed interior plan for the treatment space through an analysis of psychological factors of how the environment affects students.

An Experimental Study on the Required Performances of Roof Concrete Placed in the In-ground LNG Storage Tank (지하식 LNG 저장탱크의 지붕 콘크리트의 요구성능에 관한 실험적 연구)

  • Kwon, Yeong-Ho
    • Journal of the Korea Concrete Institute
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    • v.25 no.3
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    • pp.339-345
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    • 2013
  • This study is to derive from the required performances and the optimum mix proportion of the roof concrete placed in the in-ground LNG storage tank with a capacity of 200000 $m^3$, and propose the actual data for site concrete work. The concrete placing work without sliding and segregation in the fresh concrete condition is very important because the slope of domed roof is varied in the large range by its curvature. Also the control of hydration heat and the strength development at test ages are classified with massive section about 1.4 m thick and considered to the pre-stressing work and removal of air support after concrete placing work. Considering above condition, slump range is selected $100{\pm}25$ mm under the slope $20^{\circ}$ and $150{\pm}25$ mm over the slope $20^{\circ}$ s until 60 minutes of elapsed time. Also, the roof concrete is satisfied with compressive strength range including design strength at 91 days (30 MPa), pre-stressing work at 7 days (10 MPa), air support removal work at 21 days (14 MPa). Replacement ratio of limestone powder is determined by confined water ratio test and main design factors include water-cement ratio (W/C), sand-aggregate ratio and dosage of admixture. As test results, the optimum mix proportion of the roof concrete used low heat cement is as followings. 1) Replacement ratio of limestone powder 25% by confined water ratio test 2) Water-cement ratio 57.8% 3) Sand-aggregate ratio 42.0%. Also, test results for the adiabatic temperature rising test is satisfied with its criteria and shown the lower value compared to preceding storage tank (TK-13, 14). These required performances and the optimum mix proportion is to apply the actual construction work.

Learning Material Bookmarking Service based on Collective Intelligence (집단지성 기반 학습자료 북마킹 서비스 시스템)

  • Jang, Jincheul;Jung, Sukhwan;Lee, Seulki;Jung, Chihoon;Yoon, Wan Chul;Yi, Mun Yong
    • Journal of Intelligence and Information Systems
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    • v.20 no.2
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    • pp.179-192
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    • 2014
  • Keeping in line with the recent changes in the information technology environment, the online learning environment that supports multiple users' participation such as MOOC (Massive Open Online Courses) has become important. One of the largest professional associations in Information Technology, IEEE Computer Society, announced that "Supporting New Learning Styles" is a crucial trend in 2014. Popular MOOC services, CourseRa and edX, have continued to build active learning environment with a large number of lectures accessible anywhere using smart devices, and have been used by an increasing number of users. In addition, collaborative web services (e.g., blogs and Wikipedia) also support the creation of various user-uploaded learning materials, resulting in a vast amount of new lectures and learning materials being created every day in the online space. However, it is difficult for an online educational system to keep a learner' motivation as learning occurs remotely, with limited capability to share knowledge among the learners. Thus, it is essential to understand which materials are needed for each learner and how to motivate learners to actively participate in online learning system. To overcome these issues, leveraging the constructivism theory and collective intelligence, we have developed a social bookmarking system called WeStudy, which supports learning material sharing among the users and provides personalized learning material recommendations. Constructivism theory argues that knowledge is being constructed while learners interact with the world. Collective intelligence can be separated into two types: (1) collaborative collective intelligence, which can be built on the basis of direct collaboration among the participants (e.g., Wikipedia), and (2) integrative collective intelligence, which produces new forms of knowledge by combining independent and distributed information through highly advanced technologies and algorithms (e.g., Google PageRank, Recommender systems). Recommender system, one of the examples of integrative collective intelligence, is to utilize online activities of the users and recommend what users may be interested in. Our system included both collaborative collective intelligence functions and integrative collective intelligence functions. We analyzed well-known Web services based on collective intelligence such as Wikipedia, Slideshare, and Videolectures to identify main design factors that support collective intelligence. Based on this analysis, in addition to sharing online resources through social bookmarking, we selected three essential functions for our system: 1) multimodal visualization of learning materials through two forms (e.g., list and graph), 2) personalized recommendation of learning materials, and 3) explicit designation of learners of their interest. After developing web-based WeStudy system, we conducted usability testing through the heuristic evaluation method that included seven heuristic indices: features and functionality, cognitive page, navigation, search and filtering, control and feedback, forms, context and text. We recruited 10 experts who majored in Human Computer Interaction and worked in the same field, and requested both quantitative and qualitative evaluation of the system. The evaluation results show that, relative to the other functions evaluated, the list/graph page produced higher scores on all indices except for contexts & text. In case of contexts & text, learning material page produced the best score, compared with the other functions. In general, the explicit designation of learners of their interests, one of the distinctive functions, received lower scores on all usability indices because of its unfamiliar functionality to the users. In summary, the evaluation results show that our system has achieved high usability with good performance with some minor issues, which need to be fully addressed before the public release of the system to large-scale users. The study findings provide practical guidelines for the design and development of various systems that utilize collective intelligence.

How Did the COVID-19 Pandemic Affect Mobility, Land Use, and Destination Selection? Lesson from Seoul, Korea

  • Lee, Jiwon;Gim, Tae-Hyoung Tommy;Park, Yunmi;Chung, Hyung-Chul;Handayani, Wiwandari;Lee, Hee-Chung;Yoon, Dong Keun;Pai, Jen Te
    • Land and Housing Review
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    • v.14 no.4
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    • pp.77-93
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    • 2023
  • The COVID-19 pandemic has brought about significant social changes through government prevention and control measures, changes in people's risk perceptions, and lifestyle changes. In response, urban inhabitants changed their behaviors significantly, including their preferences for transportation modes and urban spaces in response to government quarantine policies and concerns over the potential risk of infection in urban spaces. These changes may have long-lasting effects on urban spaces beyond the COVID-19 pandemic or they may evolve and develop new forms. Therefore, this study aims to explore the potential for urban spaces to adapt to the present and future pandemics by examining changes in urban residents' preferences in travel modes and urban space use due to the COVID-19 pandemic. This study found that overall preferences for travel modes and urban spaces significantly differ between the pre-pandemic, pandemic, and post-pandemic periods. During the pandemic, preferences for travel modes and urban spaces has decreased, except for privately owned vehicles and green spaces, which are perceived to be safe from transmission, show more favorable than others. Post-pandemic preferences for travel modes and urban spaces are less favorable than pre-pandemic with urban spaces being five times less favorable than transportation. Although green spaces and medical facilities that were positively perceived during the pandemic are expected to return to the pre-pandemic preference level, other factors of urban spaces are facing a new-normal. The findings suggest that the COVID-19 pandemic has had a significant impact on urban residents' preferences for travel modes and urban space use. Understanding these changes is crucial for developing strategies to adapt to present and future pandemics and improve urban resilience.

APPLICATION OF FUZZY SET THEORY IN SAFEGUARDS

  • Fattah, A.;Nishiwaki, Y.
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 1993.06a
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    • pp.1051-1054
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    • 1993
  • The International Atomic Energy Agency's Statute in Article III.A.5 allows it“to establish and administer safeguards designed to ensure that special fissionable and other materials, services, equipment, facilities and information made available by the Agency or at its request or under its supervision or control are not used in such a way as to further any military purpose; and to apply safeguards, at the request of the parties, to any bilateral or multilateral arrangement, or at the request of a State, to any of that State's activities in the field of atomic energy”. Safeguards are essentially a technical means of verifying the fulfilment of political obligations undertaken by States and given a legal force in international agreements relating to the peaceful uses of nuclear energy. The main political objectives are: to assure the international community that States are complying with their non-proliferation and other peaceful undertakings; and to deter (a) the diversion of afeguarded nuclear materials to the production of nuclear explosives or for military purposes and (b) the misuse of safeguarded facilities with the aim of producing unsafeguarded nuclear material. It is clear that no international safeguards system can physically prevent diversion. The IAEA safeguards system is basically a verification measure designed to provide assurance in those cases in which diversion has not occurred. Verification is accomplished by two basic means: material accountancy and containment and surveillance measures. Nuclear material accountancy is the fundamental IAEA safeguards mechanism, while containment and surveillance serve as important complementary measures. Material accountancy refers to a collection of measurements and other determinations which enable the State and the Agency to maintain a current picture of the location and movement of nuclear material into and out of material balance areas, i. e. areas where all material entering or leaving is measurab e. A containment measure is one that is designed by taking advantage of structural characteristics, such as containers, tanks or pipes, etc. To establish the physical integrity of an area or item by preventing the undetected movement of nuclear material or equipment. Such measures involve the application of tamper-indicating or surveillance devices. Surveillance refers to both human and instrumental observation aimed at indicating the movement of nuclear material. The verification process consists of three over-lapping elements: (a) Provision by the State of information such as - design information describing nuclear installations; - accounting reports listing nuclear material inventories, receipts and shipments; - documents amplifying and clarifying reports, as applicable; - notification of international transfers of nuclear material. (b) Collection by the IAEA of information through inspection activities such as - verification of design information - examination of records and repo ts - measurement of nuclear material - examination of containment and surveillance measures - follow-up activities in case of unusual findings. (c) Evaluation of the information provided by the State and of that collected by inspectors to determine the completeness, accuracy and validity of the information provided by the State and to resolve any anomalies and discrepancies. To design an effective verification system, one must identify possible ways and means by which nuclear material could be diverted from peaceful uses, including means to conceal such diversions. These theoretical ways and means, which have become known as diversion strategies, are used as one of the basic inputs for the development of safeguards procedures, equipment and instrumentation. For analysis of implementation strategy purposes, it is assumed that non-compliance cannot be excluded a priori and that consequently there is a low but non-zero probability that a diversion could be attempted in all safeguards ituations. An important element of diversion strategies is the identification of various possible diversion paths; the amount, type and location of nuclear material involved, the physical route and conversion of the material that may take place, rate of removal and concealment methods, as appropriate. With regard to the physical route and conversion of nuclear material the following main categories may be considered: - unreported removal of nuclear material from an installation or during transit - unreported introduction of nuclear material into an installation - unreported transfer of nuclear material from one material balance area to another - unreported production of nuclear material, e. g. enrichment of uranium or production of plutonium - undeclared uses of the material within the installation. With respect to the amount of nuclear material that might be diverted in a given time (the diversion rate), the continuum between the following two limiting cases is cons dered: - one significant quantity or more in a short time, often known as abrupt diversion; and - one significant quantity or more per year, for example, by accumulation of smaller amounts each time to add up to a significant quantity over a period of one year, often called protracted diversion. Concealment methods may include: - restriction of access of inspectors - falsification of records, reports and other material balance areas - replacement of nuclear material, e. g. use of dummy objects - falsification of measurements or of their evaluation - interference with IAEA installed equipment.As a result of diversion and its concealment or other actions, anomalies will occur. All reasonable diversion routes, scenarios/strategies and concealment methods have to be taken into account in designing safeguards implementation strategies so as to provide sufficient opportunities for the IAEA to observe such anomalies. The safeguards approach for each facility will make a different use of these procedures, equipment and instrumentation according to the various diversion strategies which could be applicable to that facility and according to the detection and inspection goals which are applied. Postulated pathways sets of scenarios comprise those elements of diversion strategies which might be carried out at a facility or across a State's fuel cycle with declared or undeclared activities. All such factors, however, contain a degree of fuzziness that need a human judgment to make the ultimate conclusion that all material is being used for peaceful purposes. Safeguards has been traditionally based on verification of declared material and facilities using material accountancy as a fundamental measure. The strength of material accountancy is based on the fact that it allows to detect any diversion independent of the diversion route taken. Material accountancy detects a diversion after it actually happened and thus is powerless to physically prevent it and can only deter by the risk of early detection any contemplation by State authorities to carry out a diversion. Recently the IAEA has been faced with new challenges. To deal with these, various measures are being reconsidered to strengthen the safeguards system such as enhanced assessment of the completeness of the State's initial declaration of nuclear material and installations under its jurisdiction enhanced monitoring and analysis of open information and analysis of open information that may indicate inconsistencies with the State's safeguards obligations. Precise information vital for such enhanced assessments and analyses is normally not available or, if available, difficult and expensive collection of information would be necessary. Above all, realistic appraisal of truth needs sound human judgment.

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Research on the Effect of the Control Methods of Irrigation Water on the Growth and Yield of Paddy Rice. (한발기에 있어서 용수관리 방법이 수도생육과 그 수량에 미치는 영향에 관한 연구)

  • 김시원
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.13 no.1
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    • pp.2177-2190
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    • 1971
  • This experiment was made to determienthe effect of various soil moisture contents in simulated drought conditions on different stages of rice growth. The drought conditions were developed at such three rice-growing stages as transplanting, immediately after transplanting and young ear forming. Three different lengths of drought periods, which are ten days, twenty days and thirty days, were applied for each growing stage of rice. The rice variety used this experiment is Nong-rim 29. This experiment was conducted at the university farm of the Kon-Kuk University during the period of $1968{\sim}1970$. Three reprications for each of 12 treatments and split plot design were employed in this study. Bottomless wood square boxes, $1^m{\times}1^m{\times}1^m$, were burried in the test plot and box top was covered with poloyethylene sheets to avoid natural rainfall drops. Standard plots were irrigated continuously with a water depth of 40mm/day and those of drought treatments were irrigated continuously up to the beginning of the planned drought period, and they were irrigated again with a depth of 40mm/day up to the maturing stage of rice. Other methods for rice raising followed those methods developed by the Field Crops Experiment Station of the Office of Rural Development. During this experiments, climatic conditions in regard to rainfalls, sunshine hours, and temperatures were observed. According to this observation, those values measured deviate slightly from the annual means. However the growing condition of rice plants were normal. The pH value of irritation water is nearly neutral, and soils in the test plots are relatively fertile, being similar to ordinary paddy soils. Analysis of variances for number of stalks, plan-height, ear sprouting date, length of stalks, ear length, number of ears per plant, fertility, grain weitght, weight of plant, and yield were carried out. The variances for plant height, ear sprouting date, length of stalk ear length, and yield has statistical significance under drought treatments applied at three different growing stages. The variance showing the effect of lengths of drought period is highly significant for all the treatments studied except that of grain weight. The interaction between drought periods and drought treatments at different growing stages is significant for plant height, stalk length, ear length, number of ears, fertility and yield, these results indicated that droughts at different growing stages have influence on plant height, ear length, yield, and length of drought period also has strong influence on all factors studied except grain weight. The combination of drought treatments at different rice growing stages and lengths of drought periods has different effects on various agronomic characteristics, including yield. Plant height under drought treatment practiced at transplanting stage is the lowest, and drought treatment applied immediately after transplanting resulted in the least number of stalks. The effect of different lengths of drought periods on plant height and number of stalks depends signis ficantly on increasing days of drought. Ear sprouting date tends to be delayed for one or two days undedrought treatments at transplanting period and with increasing days of drought. Better yield is secured in drought treatment applied immediately after transplanting. Adverse effect war observed when drought treatment was applied at ear forming period. These effects may be attributed to the alternation of irrigation and drought causing vigorous root activity. In general, yield linearly decreases as the length of the drought period increases. The results obtained in this study demonstrate that, in order to mimimize damage due to drought, and, to save irrigation water, paddy fields, immediately after transplanting, may be not irrigated, since there is sufficient moisture in the soil, and that sufficient irrigation water should be applied again in the ear forming stage of rice plant.

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The Study on the Effects of the Economical Use of Irrigation Water by Different Irrgation Periods and Its Methods on the Growth, Yield and the Factors of Rice Plants. (절수의 시기 및 방법의 차이가 수도생육 수량과 기타 실용형태질 미치는 영향)

  • 이창구
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.10 no.1
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    • pp.1388-1393
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    • 1968
  • Higher yield in rice paddies is greatly dependent on adequately balanced and timely supply of water. A majority of rice paddy in Korea is generally irrigated by rainfall, but in many cases it has to be supplemented by artificial irrigation for optimum rice culture. Although the water requirement of rice plant is far higher than that of other crops, submerged condition of rice paddy is not necessarily required. The moisture requirement of rice plant varies with its growing stages, and it is possible to increase the irrigation efficiency through reduction of water loss due to percolation in rice paddies. An experiment was conducted on the effectiveness of economical use of water by different irrigation period and different method of cultivation. The experimental plots were set up by means of randomized block design with three duplications; (a) Alltime submerged (b) Economically controlled, and (c) Extremely controlled. Three different irrigation periods were (a) Initial stage (b) Inter-stage, and (c) last stage. The topsoil of the three plots were excavated to the depth of 30cm and then compacted with clay of 6 cm thickness. Thereafter, they were piled up with the excavated top soils, leveled and cored with clay of 6cm thickeness arround footpath in order to prevent leakage. The results obtained frome the experiments are as follows; (1) There is no difference among the three experiment plots in terms of physical and chemical contditions, soil properties, and other characteristics. (2) Colulm length and ear length are not affected by different irrigation methdos. (3) There is no difference in the mature rate and grain weight of rice for the three plots. (4) The control plot which was irrigated every three days shows an increased yield over the all the time submerged plot by 17 persent. (5) The clay lined plot whose water holding capacity was held days long, needs only to be irrigated every 7 days. (6) The clay lined plot showes an increased yield over the untreated plot; over all the time submerged plot by 18 percent, extremely controlled plot by 18 percent, and economically controled plot by 33 percent.

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A Study on the Acceptance of Convergence System of Broadcasting, and Telecommunication, and Their Relative Efficiency Focusing on IPFV (방송과 통신 융합시스템의 수용 및 상대적 효능에 관한 연구: IPTV를 중심으로)

  • Um, Myoung-Yong;Lee, Sang-Ho;Kim, Jai-Beam
    • Asia pacific journal of information systems
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    • v.19 no.3
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    • pp.25-49
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    • 2009
  • Advances in technology have resulted in the emergence of new information systems. The convergence of IT and manufacturing sectors has blurred the boundaries among industries. Also, such convergence has become established as a paradigm to build a new area. Especially the convergence of broadcasting and telecommunication, notably in the case of IPTV (Internet Protocol Television), is among the most salient examples of its kind in recent years as a major case of disruptive technology innovation. Despite its much fanfare, such convergence, however, has not fulfilled the expectation; it has not produced positive economic effects while negatively affecting the growth of IPIV. Stakeholders in and around IPIV including telecommunication companies, broadcasting corporations, and government bodies wish to gain control of IPTV under their wings. IPTV has drifted in the midst of conflicts among the stakeholders in and around IPTV, particularly telecommunication and broadcasting organizations in a broad sense. Our empirical research intends to deal with how audiences accept IPTV and how firms provide IPTV services to utilize their resources. Three research questions in this paper include, first, whether Technology Acceptance Model (TAM) can sufficiently explain the acceptance of IPTV as an information system. The second question concerns with empirically testing the playful aspect of IPTV to increase its audience acceptance. Last, but not least, this paper deals with how firms can efficiently and effectively allocate their limited resources to increase IPTV viewers. To answer those three main questions of our study, we collect data from 197 current subscribers of high speed internet service and/or cable/satellite television. Empirical results show that 'perceived usefulness (PU) $\rightarrow$ Intention to use' and 'perceived ease of use (PEU) $\rightarrow$ Intention to use' are significant. Also, 'perceived ease of use' is significantly related to 'perceived usefulness.' Perceived ease of handling IPTV without much effort can positively influence the perceived value of IPTV. In this regard, engineers and designers of IPTV should pay more attention to the user-friendly interface of IPTV. In addition, 'perceived playfulness (PP)' of IPTV is positively related to 'intention to use'. Flow, fun and entertainment have recently gained greater attention in the research concerned with information systems. Such attention is due to the changing features of information systems in recent years that combine the functional and leisure attributes. These results give practical implications to the design of IPTV that reflects not just leisure but also functional elements. This paper also investigates the relationship between 'perceived ease of use (PEU)' and 'perceived playfulness (PP).' PEU is positively related to pp. Audiences without fear can be attracted more easily to the user-friendly IPTV, thereby perceiving the fun and entertainment with ease. Practical implications from this finding are that, to attract more interest and involvement from the audience, IPTV needs to be designed with similar or even more user friendly interface. Of the factors related to 'intention to use', 'perceived usefulness (PU)' and 'perceived ease of use (PEU)' have greater impacts than 'perceived playfulness (PP).' Between PU and PEU, their impacts on 'intention to use' are not significantly different statistically. Managerial implications of this finding are that firms in preparation for the launch of IPTV service should prioritize the functions and interface of IPTV. This empirical paper also provides further insight into the ways in which firms can strategically allocate their limited resources so as to appeal to viewers, both current and potential, of IPTV.

Evaluation for Soil Moisture Stabilization and Plant Growth Response in Horizontal Biofiltration System Depending on Wind Speed and Initial Soil Moisture (풍속과 초기 토양수분에 따른 평면형 바이오필터 내 토양수분 안정화 및 식물 생육반응 평가)

  • Choi, Bom;Chun, Man Young;Lee, Chang Hee
    • Korean Journal of Plant Resources
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    • v.27 no.5
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    • pp.546-555
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    • 2014
  • The final aim of this study is to develop a biofiltration system integrated with plant vegetation for improving indoor air quality effectively depending on indoor space and characteristics. However, to approach this final goal, several requirements such as constant pressure drops (PDs) and soil moisture contents (SMCs), which influence the capacity design for a proper ventilation rate of biofiltration system, should be satisfied. Thus, this fundamental experiment was carried out to adjust a proper wind speed and to ensure a stabilization of initial SMCs within biofilter for uniform distribution of SMCs and PDs, and for normal plant growth, especially avoiding root stress by wind. Therefore, we designed horizontal biofliter models and manufactured them, and then calculated the ventilation rate, air residence time, and air-liquid ration based on the biofilter depending on three levels of wind speed (1, 2, and $3cm{\cdot}s^{-1}$). The relative humidity (RH) and PD of the humidified air coming out through the soil within the biofilter, and SMC of the soil and plant growth parameters of lettuce and duffy fern grown within biofilter were measured depending on the three levels of wind speed. As a result of wind speed test, $3{\cdot}sec^{-1}$ was suitable to keep up a proper RH, SMC, and plant growth. Thus, the next experiment was set up to be two levels of initial SMCs (low and high initial SMC, 18.5 and 28.7%) within each biofilter operated and a non-biofiltered control (initial SMC, 29.7%) on the same wind speed ($3cm{\cdot}sec^{-1}$), and measured on the RH and PD of the air coming out through the soil within the biofilter, and SMC of the soil and plant growth parameters of Humata tyermani grown within biofilter. This result was similar to the first results on RHs, SMCs, and PDs keeping up with constant levels, and three SMCs did not show any significant difference on plant growth parameters. However, two biofiltered SMCs enhanced dry weights of the plants slightly than non-biofiltered SMC. Thus, the stability of this biofiler system keeping up major physical factors (SMC and PD) deserved to be adopted for designing an advanced integrated biofilter model in the near future.