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VIDEO GAME CULTURE AND INTERACTIVITY -An exploration of digital interactive media through a metaphorical approach to video game culture-

  • U, Tak
    • 한국게임학회지
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    • v.6 no.1
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    • pp.70-72
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    • 2009
  • This research is focused on defining interaction within the context of digital media and creating a multi cultural definition of interactivity. The concept of multi digital culture and a definition of interaction in digital media have often been overlooked by other researchers and this has caused the emergence of many different notions on this issue. As a result of these varied notions of the concept, public confusion has arisen regarding interactivity. The main purpose of this research is to find a suitable multi definition of interaction through examining local digital culture. In order to analogise multi digital culture, the video game culture is employed as a metaphor to interpret local digital culture. The reason for this is that a specific national culture can be easily identified within the video game culture. Four countries, South Korea, Japan, the U.S. and the UK have been chosen for comparison purposes. Case study, questionnaire and publicly accessible video game related data, such as, video game charts, are used for formalising and analysing unique local digital culture. The Heyri POP UP IMAGE Festival, S. Korea, was also used as a pilot study, with some of the above research methods being employed to analyse South Korean digital culture. In relation to western cases, interview and questionnaire were primarily used. The data from the case countries was carefully compared and analysed and then it became the basis of a theory of multi definition of interaction in digital media. The case study employed the cultural metaphor for this research and in addition video game culture related questionnaires and interviews with experts of interactive art genre, regarding new notions of digital interaction were utilised. The survey was conducted simultaneously in the four different cultural case nations of this research. Twenty respondents from each case nation participated in the survey, in order to investigate firstly, the existence of 'local digital culture' and secondly, the trends and phenomena of 'digital culture' in these four different 'local digital cultural areas'. In terms of interviews with experts of the interactive art genre, these were focused on obtaining their understanding of contemporary digital culture in their research. Using gathered data from the observation of local digital culture, the basic theory of interaction and the terminology of interaction are reformed. Localised definitions of interaction on digital media, control based interaction and communication based interaction are presented, in order to identify a 'locality' in terms of various contemporary digital cultures. As a result of analysing digital culture, new definitions of 'multi definition of digital interaction' were formulated. As mentioned above, 'control' and 'communication' based interaction were initiated, based on 'user to media' relationships. Based on the degree of physical interaction, 'liminal' and 'transitive' interactions were initiated. Less physical digital interaction is named 'liminal' interaction and more physical digital interaction is named' transitive' interaction. These new definitions of interaction were applied to the real world examples of uses of digital interaction, such as, digital interactive installation artworks and video games. The newly defined meaning of digital interaction can be applied to analysing digital interactive installation artworks and possibly indicate their future development and the prospects of future electronic games. Three leading digital interactive artists were selected for this analysis and their works were studied in terms of the implementation of 'multi definition of digital interaction'. Throughout these processes, the meaning of 'communication' in digital interactive media was emphasised. Many of the selected artists' digital installations were focused on 'communication' or 'interaction between each user through digital media', rather than the concept of 'control' in digital interaction, otherwise termed, 'communication with digital media'. In their artworks, interaction between each audience was digitally engaged within the physical interactive environment which was created by the digital media. Both the audience's action and all the reaction throughout the interaction between the audiences, triggered the digital media' s reaction. This audience-audience-media interaction is the key to understanding the concept of 'communication' in physical digital media and it is the main interactive concept upon which the selected digital interactive installation artists for this research and many other artists from similar fields, are concentrating their efforts. In the case of the video game, a similar trend was noticed to that of digital interactive installations. Based on this research's 'multi definition of digital interaction', the video game has evolved from the early stage of being conventional game, which was focused on control based interaction, to the on-line game which was focused on communication based interaction, to physical interactive games, such as, Nintendo Wii, which are focused on more physical interaction and finally, the ubiquitous interactive game, which is mainly concentrated on the concept of 'communication' in physical digital interaction. It is possible that this evolution of the video game concept of interaction is comparable to the progress of digital interactive artworks. This view is based on the fact that both genres show evidence that they are developing in the direction of the concept of 'communication', in terms of physical digital interaction. The important emphasis of this research's results is 'locality' and 'communication' in physical digital interaction. The existence of different digital culture trends, which were assessed by the 'multi definition of digital interaction', can explain the concept of 'locality' in digital interaction. This meaning of 'locality' may assist in understanding contemporary digital culture and can reduce possible misunderstanding as regards 'local' digital culture. In the application of the concept of digital interaction to the field of either artworks or video games, it is possible to form the opinion that an innovative concept of physical digital interaction is 'communication' within this context. This concept and its applications can improve the potential of both digital interactive culture and technology.

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A Comparative Analysis between Photogrammetric and Auto Tracking Total Station Techniques for Determining UAV Positions (무인항공기의 위치 결정을 위한 사진 측량 기법과 오토 트래킹 토탈스테이션 기법의 비교 분석)

  • Kim, Won Jin;Kim, Chang Jae;Cho, Yeon Ju;Kim, Ji Sun;Kim, Hee Jeong;Lee, Dong Hoon;Lee, On Yu;Meng, Ju Pil
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.35 no.6
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    • pp.553-562
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    • 2017
  • GPS (Global Positioning System) receiver among various sensors mounted on UAV (Unmanned Aerial Vehicle) helps to perform various functions such as hovering flight and waypoint flight based on GPS signals. GPS receiver can be used in an environment where GPS signals are smoothly received. However, recently, the use of UAV has been diversifying into various fields such as facility monitoring, delivery service and leisure as UAV's application field has been expended. For this reason, GPS signals may be interrupted by UAV's flight in a shadow area where the GPS signal is limited. Multipath can also include various noises in the signal, while flying in dense areas such as high-rise buildings. In this study, we used analytical photogrammetry and auto tracking total station technique for 3D positioning of UAV. The analytical photogrammetry is based on the bundle adjustment using the collinearity equations, which is the geometric principle of the center projection. The auto tracking total station technique is based on the principle of tracking the 360 degree prism target in units of seconds or less. In both techniques, the target used for positioning the UAV is mounted on top of the UAV and there is a geometric separation in the x, y and z directions between the targets. Data were acquired at different speeds of 0.86m/s, 1.5m/s and 2.4m/s to verify the flight speed of the UAV. Accuracy was evaluated by geometric separation of the target. As a result, there was an error from 1mm to 12.9cm in the x and y directions of the UAV flight. In the z direction with relatively small movement, approximately 7cm error occurred regardless of the flight speed.

Physico-Chemical Properties of Soils at Red Pepper, Garlic and Onion Cultivation Areas in Korea (우리나라 고추, 마늘 및 양파 주산지 밭토양의 물리·화학적 특성)

  • Sohn, Bo-Kyoon;Cho, Ju-Sik;Kang, Jong-Gu;Cho, Ja-Yong;Kim, Kil-Yong;Kim, Hyun-Woo;Kim, Hong-Lim
    • Korean Journal of Soil Science and Fertilizer
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    • v.32 no.2
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    • pp.123-131
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    • 1999
  • To get the basic information for the improvement of the optimum levels of upland soil fertility and fertilizer application, the soil samples in two hundred fifteen site were collected from the major condiment vegetable cultivation areas such as red pepper, garlic and onion fields. Physico-chemical properties of the soil samples were investigated. Soil texture distribution of soil samples in red pepper, garlic and onion cultivation areas was in order of loam (L), sandy loam (SL), silt loam (SiL) and clay loam (CL) (35.4, 31.6, 14.9 and 7.0%, respectively). The average pH of soil in garlic and onion cultivation areas were over pH 6.0, whereas in red pepper was under pH 5.5. The frequency distribution of soil pH in total sampling sites were 58.7% in under pH 6.0 and 21.4% in below pH 5.0, in contrast to 10.3% in over pH 7.0. The organic matter contents were in the range of $20{\sim}30g\;kg^{-1}$, and the onion field soils was a little higher than those in red pepper or garlic. The available phosphate contents were in the range of $719{\sim}746mg\;kg^{-1}$ and were not different among in red pepper, garlic and onion. The frequency distribution of available phosphate in total sampling sites were found 62.8% of above $600mg\;kg^{-1}$, which was over the standard level for upland soil improvement, and then 22.3% was exceeded $1,000mg\;kg^{-1}$, especially. In the exchangeable cations, the K and Ca contents in garlic (1.27 and $9.11cmol\;kg^{-1}$) and onion (1.20 and $8.39cmol\;kg^{-1}$) were higher than in red pepper (0.96 and $5.87cmol\;kg^{-1}$), respectively. The Mg contents in garlic field soils ($2.17cmol\;kg^{-1}$) were higher than those in red pepper and onion (1.51 and $1.80cmol\;kg^{-1}$). This exchangeable K, Ca and Mg contents were higher than the standard level for upland soil improvement. The contents of microelement were ranged in $54.3{\sim}60.1mg\;kg^{-1}$ for Fe, $31.3{\sim}42.3mg\;kg^{-1}$ for Mn, $1.7{\sim}2.3mg\;kg^{-1}$ for Cu and $4.8{\sim}5.5mg\;kg^{-1}$ for Zn, respectively.

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A Case Study on Center of Gravity Analysis when Performing Uchimata by Posture and Voluntary Resistance Levels of Uke in Judo[ll] (유도 허벅다리걸기 기술발휘 시 받기의 자세와 저항수준에 따른 중심변인 분석 사례연구[II])

  • Kim, Eui-Hwan;Kim, Sung-Sup;Chung, Chae-Wook
    • Korean Journal of Applied Biomechanics
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    • v.15 no.1
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    • pp.237-257
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    • 2005
  • It was to study as a following-research of "A Case Study on Center of Gravity(COG) Analysis when Performing Uchimata(inner thigh reaping throw) by Posture and Voluntary Resistance Levels(VRL) of Uke in Judo[I]". The purpose of this study was to analyze the COG variables when performing uchimata(inner thigh reaping throw) by two postures and voluntary resistance levels(VRL) of uke(reciver) in Judo. The subjects, who were one male judoka(YH) for 1992 Barcelona Olympic Games Olympian(silver medalist), and one male trainee; Y.I.University representative member (SDK), and were filmed on two S-VHS 16mm video cameras(60fields/sec.) through 3-dimensional motion analysis methods, that postures of uke were shizenhontai (straight natural posture) and jigohontai(straight defensive posture), VRL of uke were 0% and 100%, respectively. The kinematical variable was COG variable, distance of COG, and distance of resultant COG between uke and tori(the thrower), velocity and acceleration of COG. The data of this study collection were digitized by SIMI Motion Program computed the mean values and the standard deviation calculated for each variables. When performing uchinmata according to each posture and VRL of uke and classifying. From the data analysis and discussion, the conclusions were as follows : 1. Displacement of COG Subject YH, COG was the highest in kuzushi(balance -breaking), vertical COG was low when following in tsukuri(positioning; set-up), kake(application; execution), and COG was pattern of same character each postures and resistance, respectively. Subject SDK, COG was low from kumikata(engagement positioning) to kake, and COG was that each postures and resistance were same patterns, respectively. Subject YH, SDK, each individual, postures and resistance, vertical COG was the lowest in kake phase, when performing. 2. Distance of COG between uke and tori The distance of COG between uke and tori when performing, subject YH was $0.64{\sim}0.70cm$ in kumikata, $0.19{\sim}0.28cm$ in kake, and SDK was $0.68{\sim}0.72cm$ in kumikata, $0.30{\sim}0.42\;cm$ in kake. SDK was wider than YH. 3. Distance of resultant COG between uke and tori The distance of resultant COG between uke and tori when performing, subject YH was $0.27{\sim}0.73cm$ from kumikata to kake. and SDK was $0.14{\sim}0.34cm$ in kumikata, $0.28{\sim}0.65cm$ in kake. Jigohontai(YH:$0.43{\sim}0.73cm$,SDK:$0.59{\sim}0.65cm$) was more moved than shizenhontai(YH:$0.27{\sim}0.53cm$, SDK: $0.28{\sim}\;0.34cm$). 4. Velocity of COG The velocity of COG when performing uchimata, subject YH was fast anterior-posterior direction in kuzushi, ant.-post. and vertical direction fast in tsukuri and kake. SDK was lateral, ant.-post. and vertical direction in kuzushi, ant.-post. and vertical direction in tsukuri and ant.-post. direction in take, respectively. 5. Acceleration of COG The acceleration of COG when performing uchimata, The trend of subject YH was showed fast vertical direction in kuzushi and tsukuri, ant.-post. and vertical direction fast in kake. The trends of SDK showed lateral direction in kuzushi, lateral and ant.-post. direction in tsukuri and ant.-post. direction in kake, respectively.

Inorganic Nutrient Uptake Pattern of Vegetable Crops in Highland (고랭지 주요 채소작물의 무기성분 흡수 특성)

  • Lee, Jeong-Tae;Lee, Gye-Jun;Ryu, Jong-Soo;Zhang, Yong-Seon;Hwang, Seon-Woong;Park, Chol-Soo
    • Korean Journal of Soil Science and Fertilizer
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    • v.43 no.5
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    • pp.616-623
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    • 2010
  • Plant samples from 49 sites for Chinese cabbage, 28 sites for radish, 16 sites for cabbage, 8 sites for head lettuce, 20 sites for onion from farmers' and experimental fields in highland of Korea were collected and analyzed to find out the uptake patterns of nitrogen (N), phosphorus (P) and potassium (K) by altitude. Dry weight and uptake of N, P and K were increased at higher altitude in most vegetable crops. Nutrition uptake by Chinese cabbage was 163 ~ 283 kg $ha^{-1}$ for N, 42 ~ 69 kg $ha^{-1}$ for $P_2O_5$ and 146 ~ 270 kg $ha^{-1}$ for $K_2O$ according to altitude. Nutrient uptake by radish according to altitude was 153~159 kg $ha^{-1}$ for N, 38 ~ 46 kg $ha^{-1}$ for $P_2O_5$, and 151 ~ 185 kg $ha^{-1}$ for $K_2O$. In case of cabbage, the plant uptakes of N, P, and K were increased at altitudes of 600 ~ 1,000 m. Nutrient uptake of cabbage was 280 ~ 348 kg $ha^{-1}$ for N, 34 ~ 87 kg $ha^{-1}$ for $P_2O_5$, and 209 ~ 290 kg $ha^{-1}$ for $K_2O$ according to altitude. Uptakes of N-$P_2O_5-K_2O$ by head lettuce at an altitude of 800 ~ 850 m were 93-26-126 kg $ha^{-1}$, respectively. Uptakes of N-$P_2O_5-K_2O$ by onions at an altitude of 600 ~ 800 m were 313-140-234 kg $ha^{-1}$, respectively, but there was no tendency in nutrition uptake patterns by altitude. Small cultivation areas used for leaf vegetable crops do not have fertilizer recommendation standards in alpine regions. It might be preferable to use a correction factor equivalent to the index of available nutrient uptake for the determination of N, P and K fertilizer application rates.

Prediction of field failure rate using data mining in the Automotive semiconductor (데이터 마이닝 기법을 이용한 차량용 반도체의 불량률 예측 연구)

  • Yun, Gyungsik;Jung, Hee-Won;Park, Seungbum
    • Journal of Technology Innovation
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    • v.26 no.3
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    • pp.37-68
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    • 2018
  • Since the 20th century, automobiles, which are the most common means of transportation, have been evolving as the use of electronic control devices and automotive semiconductors increases dramatically. Automotive semiconductors are a key component in automotive electronic control devices and are used to provide stability, efficiency of fuel use, and stability of operation to consumers. For example, automotive semiconductors include engines control, technologies for managing electric motors, transmission control units, hybrid vehicle control, start/stop systems, electronic motor control, automotive radar and LIDAR, smart head lamps, head-up displays, lane keeping systems. As such, semiconductors are being applied to almost all electronic control devices that make up an automobile, and they are creating more effects than simply combining mechanical devices. Since automotive semiconductors have a high data rate basically, a microprocessor unit is being used instead of a micro control unit. For example, semiconductors based on ARM processors are being used in telematics, audio/video multi-medias and navigation. Automotive semiconductors require characteristics such as high reliability, durability and long-term supply, considering the period of use of the automobile for more than 10 years. The reliability of automotive semiconductors is directly linked to the safety of automobiles. The semiconductor industry uses JEDEC and AEC standards to evaluate the reliability of automotive semiconductors. In addition, the life expectancy of the product is estimated at the early stage of development and at the early stage of mass production by using the reliability test method and results that are presented as standard in the automobile industry. However, there are limitations in predicting the failure rate caused by various parameters such as customer's various conditions of use and usage time. To overcome these limitations, much research has been done in academia and industry. Among them, researches using data mining techniques have been carried out in many semiconductor fields, but application and research on automotive semiconductors have not yet been studied. In this regard, this study investigates the relationship between data generated during semiconductor assembly and package test process by using data mining technique, and uses data mining technique suitable for predicting potential failure rate using customer bad data.

The development direction of vocational education teachers' fostering of china based on vocational teachers specialization and vocational disciplines (직업교사 전문화 및 직업과학 학과발전에 기반한 중국 직업교육 교사양성 전망 -UNESCO '국제 직업교사 석사 교육과정 구성표준'을 중심으로-)

  • Yin, Zi-Long;Zhao, Zhi-Qun;Nam, Seung-Kwon;Choi, Won-Sik
    • 대한공업교육학회지
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    • v.35 no.2
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    • pp.70-81
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    • 2010
  • The purpose of this study is to introduce formation 'International framework curriculum for a Master Degree for TVET teachers and lectures' to present implications about fostering Chinese vocational teachers and to analyze the contents related to it. In 2004, UNFSCO composed formation International framework curriculum for a Master Degree for TVET teachers and lectures ("framework curriculum") to improve the ability of professionals in the vocational education and training fields including teachers and training leaders as well as to promote international academic exchange. Universities which introduce the framework curriculum should form specialized committee and carry out education considering the specific situation including other universities' situation, students' ability, educational certification system, etc. The framework curriculum should include the latest trends of the development of international vocational education science and carry out united educational learning between several internal or external high schools. UNFSCO tries to promote the development of educational learning and study of basic departments of vocational education such as vocational educational learning theory, vocational science, etc through the framework curriculum and to improve knowledge of vocational educational teachers and realize specialization of them. The number of universities that established the master's degree of vocational education in China is approx. 20 and the number of students that they collect every year. As for the plans of the master's degree of vocational teachers in each university, the courses about the practical problems like educational courses and educational learning are insufficient. But the framework curriculum thinks that educational learning of application theory is more important and emphasizes practice about the specific area and educational learning much more. Utilization of preceding experiences of advanced countries has the important meaning in search of models that foster Chinese vocational teachers and departmental system. The framework curriculum implies several useful points in installment of majors and educational process of the process that fosters Chinese vocational teachers.

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Competition between Crop and Weed and Weed Control in Dry Direct Seeded Rice (벼 직파재배(直播栽培)의 잡초(雜草)와 작물간(作物間)의 경합(競合) 및 방제(防除))

  • Yeun, K.B.;Kim, K.U.;Shin, D.H.;Lee, I.J.;Jung, J.W.;Kim, H.K.
    • Korean Journal of Weed Science
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    • v.11 no.3
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    • pp.178-186
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    • 1991
  • This study was conducted to evaluate the major weeds occurred in direct seeded rice and their compition with rice, and to establish the effective weed control method. The important weeds occurring in dry direct seeded rice were Echinochloa crusgalli, Cyperus amuricus, Rorippa islandica, etc. Among them, Echinochloa crusgalli was the most dominant weed species. In view of the Simpson's dominance index, the maximum number of the weeds was observed at 30 days after seeding, showing 0.26, but decreased as the time passed. In other hand, Simpson's dominance index of weed dry weight increased from 0.09 at 15DAS(days after seeding) to 0.28 at 60DAS indicating that particular weed such as barnyardgrass was dominating the fields. The plant height and the tiller number of rice in the dry direct seeded rice were not greatly affected by the time and duration of competition with weeds, but rice yield was greatly influenced by them. The yield reduction was observed when compition between rice and weeds were initiated at 20 to 40 DAS till the harvesting time. The highest weed control efficacy was observed at the treatment of systematic herbicide application such as soil applied Butachlor followed by Mefenacet/Bensulfuron-methyl/Dymron at 30 DAS after seeding, and soil applied Dimepiperate/Bensulfuron-methyl mixture as a preemergence type gave also an excellent control.

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The Application of Operations Research to Librarianship : Some Research Directions (운영연구(OR)의 도서관응용 -그 몇가지 잠재적응용분야에 대하여-)

  • Choi Sung Jin
    • Journal of the Korean Society for Library and Information Science
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    • v.4
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    • pp.43-71
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    • 1975
  • Operations research has developed rapidly since its origins in World War II. Practitioners of O. R. have contributed to almost every aspect of government and business. More recently, a number of operations researchers have turned their attention to library and information systems, and the author believes that significant research has resulted. It is the purpose of this essay to introduce the library audience to some of these accomplishments, to present some of the author's hypotheses on the subject of library management to which he belives O. R. has great potential, and to suggest some future research directions. Some problem areas in librianship where O. R. may play a part have been discussed and are summarized below. (1) Library location. It is usually necessary to make balance between accessibility and cost In location problems. Many mathematical methods are available for identifying the optimal locations once the balance between these two criteria has been decided. The major difficulties lie in relating cost to size and in taking future change into account when discriminating possible solutions. (2) Planning new facilities. Standard approaches to using mathematical models for simple investment decisions are well established. If the problem is one of choosing the most economical way of achieving a certain objective, one may compare th althenatives by using one of the discounted cash flow techniques. In other situations it may be necessary to use of cost-benefit approach. (3) Allocating library resources. In order to allocate the resources to best advantage the librarian needs to know how the effectiveness of the services he offers depends on the way he puts his resources. The O. R. approach to the problems is to construct a model representing effectiveness as a mathematical function of levels of different inputs(e.g., numbers of people in different jobs, acquisitions of different types, physical resources). (4) Long term planning. Resource allocation problems are generally concerned with up to one and a half years ahead. The longer term certainly offers both greater freedom of action and greater uncertainty. Thus it is difficult to generalize about long term planning problems. In other fields, however, O. R. has made a significant contribution to long range planning and it is likely to have one to make in librarianship as well. (5) Public relations. It is generally accepted that actual and potential users are too ignorant both of the range of library services provided and of how to make use of them. How should services be brought to the attention of potential users? The answer seems to lie in obtaining empirical evidence by controlled experiments in which a group of libraries participated. (6) Acquisition policy. In comparing alternative policies for acquisition of materials one needs to know the implications of each service which depends on the stock. Second is the relative importance to be ascribed to each service for each class of user. By reducing the level of the first, formal models will allow the librarian to concentrate his attention upon the value judgements which will be necessary for the second. (7) Loan policy. The approach to choosing between loan policies is much the same as the previous approach. (8) Manpower planning. For large library systems one should consider constructing models which will permit the skills necessary in the future with predictions of the skills that will be available, so as to allow informed decisions. (9) Management information system for libraries. A great deal of data can be available in libraries as a by-product of all recording activities. It is particularly tempting when procedures are computerized to make summary statistics available as a management information system. The values of information to particular decisions that may have to be taken future is best assessed in terms of a model of the relevant problem. (10) Management gaming. One of the most common uses of a management game is as a means of developing staff's to take decisions. The value of such exercises depends upon the validity of the computerized model. If the model were sufficiently simple to take the form of a mathematical equation, decision-makers would probably able to learn adequately from a graph. More complex situations require simulation models. (11) Diagnostics tools. Libraries are sufficiently complex systems that it would be useful to have available simple means of telling whether performance could be regarded as satisfactory which, if it could not, would also provide pointers to what was wrong. (12) Data banks. It would appear to be worth considering establishing a bank for certain types of data. It certain items on questionnaires were to take a standard form, a greater pool of data would de available for various analysis. (13) Effectiveness measures. The meaning of a library performance measure is not readily interpreted. Each measure must itself be assessed in relation to the corresponding measures for earlier periods of time and a standard measure that may be a corresponding measure in another library, the 'norm', the 'best practice', or user expectations.

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Changes in Inorganic Phosphorus Fractions in P Accumulated Plastic Film House Soils under Different Cropping Condition (인산축적 시설 재배지 토양에서 작물재배에 따른 무기태 인의 형태별 함량 변화)

  • Jin, Sheng-Ai;Lee, Sang-Mo;Choi, Woo-Jung;Yoo, Sun-Ho
    • Korean Journal of Soil Science and Fertilizer
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    • v.34 no.4
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    • pp.255-264
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    • 2001
  • This study was conducted to investigate changes in inorganic phosphorus fractions in phosphorus accumulated plastic film house soils under cropping condition. Pot experiment was conducted with surface soils taken from plastic film house fields cultivated for 3, 8 and 16 years. Phosphorus fertilizer was applied at the rates of 0 (P0), $100kg\;ha^{-1}$ (recommended application rate. P1) and $200kg\;ha^{-1}$ (P2) as fused phosphate. Crops were grown sequentially in the order of corn-Chinese cabbage-Chinese cabbage-corn for 3 years. The content of easily soluble-P fraction was decreased with cropping. There were significantly positive relationship not only between the contents of easily soluble-P and the amounts of soil available P ($r=0.839^{**}{\sim}0.952^{**}$ for Bray-1 P, $r=0.895^{**}{\sim}0.967^{**}$ for Lancaster P, and $r=0.491^{**}{\sim}0.821^{**}$ for Olsen P), but also between the amounts of P absorbed by plants and the amounts of easily soluble P decreased ($r=0.644^{**}{\sim}0.822^{**}$). The decrease of easily soluble-P during cropping period could be described by a first-order reaction. The number of cropping times needed to decrease the content of easily soluble-P to an index level of $0.2mg\;kg^{-1}$, which is commonly reported as the desired concentration for soil P, was predicted in the range of 26~33 cropping times by using the equations. Regardless of P fertilization, the proportion of Al-P to total P was little varied during cropping period, but the proportion of Fe-P to total P increased with cropping. Although the content of Ca-P was high before cropping, the proportion of Ca-P to total P was increased with cropping. The proportion of reductant soluble-P to total P was little varied for P fertilizer treatment but was increased for no P fertilizer treatment. The residual-P was decreased during cropping period due to the absorption by crops and the conversion to other inorganic P fractions.

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