• 제목/요약/키워드: HSPDA

검색결과 6건 처리시간 0.015초

HSPDA 모형의 대규모 상수관망에의 적용 (Application of HSPDA Model to Large Water Network)

  • 백천우;전환돈;김중훈
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2007년도 학술발표회 논문집
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    • pp.2084-2088
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    • 2007
  • 상수관망의 수리해석기법은 demand-driven analysis(DDA)와 pressure-driven analysis(PDA)로 구분할 수 있다. 관거 파괴나 용수수요 급증과 같이 용수공급시스템이 비정상상태인 경우 절점의 용수수요는 항상 만족한다는 가정을 사용하는 DDA의 경우 비현실적인 결과를 줄 수 있으며, 절점수요와 절점수두를 동시에 고려하는 PDA의 개념을 이용한 관망의 수리해석이 필요하다. PDA의 개념을 사용하여 개발된 기존의 많은 모형들은 복잡한 실제관망에는 적용이 불가능한 문제점들을 가지고 있으며, 본 연구에서는 화음탐색법(Harmony Search, HS) EPANET의 toolkit을 연계하여 개발된 HSPDA모형의 실제 대규모 상수관망에의 적용성을 검토하였다. 실제 대규모관망에의 적용성 향상을 위해 화음탐색법의 새로운 인자인 PIR를 제안하였으며 적용결과 새롭게 제안된 PIR은 HSPDA모형의 최적해탐색효율을 획기적으로 향상시켰으며, HSPDA모형을 이용한 실제 대규모관망의 비정상상태 수리모의가 가능한 것으로 판단된다.

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HSPDA 모형 및 ADF index를 이용한 상수관망의 신뢰도 산정 (Estimation of the Reliability of Water Distribution Systems using HSPDA Model and ADF Index)

  • 백천우;전환돈;김중훈
    • 한국수자원학회논문집
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    • 제43권2호
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    • pp.201-210
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    • 2010
  • 본 연구에서는 HSPDA모형을 기반으로 한 상수관망의 신뢰도분석 방안을 제안하였다. 대표적인 상수관망의 신뢰도분석 방법으로는 수량과 수압의 확보가 불가능한 수요절점을 산정하고 필요수량/공급가능수량 혹은 압력확보절점수/전체절점수 등을 계산하여 상수관망이 얼마나 신뢰할 수 있는가를 판단하는 것이 있다. 이를 계산하기 위해서는 수리모형을 이용한 상수관망의 모의가 필요하나 절점의 압력과는 상관없이 항상 모든 용수량은 공급가능하다는 가정을 사용하는 Demand-Driven Analysis (DDA) 를 신뢰도 분석에 사용할 경우 신뢰도가 과소 산정될 수 있으며, 절점수요는 절점수두에 비례한다는 가정을 사용하는 Pressure-Driven Analysis (PDA)의 적용이 필요하다. 그러나 기존에 수행된 많은 연구에서는 관망의 특성에 따라 제한적인 적용성을 가지는 PDA 모형과 semi-PDA모형이 비정 상운영상태의 상수관망 수리모의에 이용되었고 이로 인하여 정확한 상수관망의 신뢰도 산정이 어려웠다. 본 연구에서는 기존의 PDA모형의 가지는 단점을 보완한 HSPDA 모형과 Available Demand Fraction (ADF) 지수를 이용하여 상수관망의 신뢰도 산정이 가능한 모형을 제안하였다. HSPDA를 활용하여 상수관망의 비정상운영상태를 모의하고, 이를 이용하여 절점별 ADF 지수를 산정, 상수관망의 신뢰도를 산정하였다. 제안된 신뢰도분석기법을 대상관망에 적용하여 기존의 연구결과와 비교하였으며, 이를 바탕으로 수립 가능한 신뢰도 확보방안을 제시하였다.

HSPDA모형과 거리척도방법을 이용한 상수관망의 신뢰성분석 (Estimating the Reliability of Water Distribution Systems Using HSPDA Model and Distance Measure Method)

  • 백천우;전환돈;김중훈
    • 한국수자원학회논문집
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    • 제43권9호
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    • pp.769-780
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    • 2010
  • '위상적 평가'와 '수리학적 평가'를 통해 수요절점에서 필요한 수량을 필요한 압력으로 충분히 공급할 수 있는지의 여부를 정량화하고 이를 신뢰성의 산정을 위한 기준으로 사용하는 것은 대표적인 상수관망시스템의 신뢰성산정 방법이다. 하지만 '수리학적 평가'를 이용한 수요절점에서의 압력확보 여부를 신뢰성 산정에 사용한 기존의 연구들은 'Demand-Driven Analysis의 사용'과 '사용성의 미고려'라는 두 가지 측면에 있어서 문제가 있다. 또한 비정상상태인 상수관망시스템의 수리모의 적합한 Pressure-Driven Analysis를 이용한 연구들도 신뢰성 산정에 있어 가능공급량만을 고려하고 사용성을 고려하지 않아, Pressure-Driven Analysis의 장점이 효율적으로 사용되지 않은 단점이 있다. 본 연구에서는 기 개발 된 Pressure-Driven Analysis 모형인 HSPDA모형과, 거리척도 방법을 이용하여 수량과 수압을 동시에 고려하는 신뢰성 분석기법을 제안하였다. 제안된 기법을 상수관망에 적용하여 기존의 연구결과와 비교하였고 이를 바탕으로 수립 가능한 신뢰성 확보방안을 제시하였다.

HSPDA-SKT.KTF,3Q 서비스 돌입.이젠 3.5G

  • 심우성
    • 정보화사회
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    • 통권178호
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    • pp.18-19
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    • 2006
  • SK텔레콤과 KTF 등 W-CDMA 사업자들의 2006년 화두는 단연 'HSDPA'라고 할 수 있다. 3.5G 이동통신으로 일컬어지는 HSDPA는 이론상 최대 속도 14Mbps, 실제 속도 역시 3Mbps 이상을 구현할 것으로 보여 화상전화 정도만을 장점으로 내세웠던 WCDMA와는 분명히 차별점이 있기 때문이다. 특히 KT가 주도하는 와이브로 서비스가 4월경 서비스될 예정이기 때문에 이통사들의 HSDPA 서비스개시도 당초 예상보다 대거 앞당겨 빠르면 7월경 이뤄질 전망이다.

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WCDMA 이동통신 단말기 수요예측에 관한 연구 (A Study on Forecasting the Demand of WCDMA Mobile Phones)

  • 이상훈;이병철;김윤배;김재범
    • 한국시뮬레이션학회논문지
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    • 제15권4호
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    • pp.153-160
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    • 2006
  • 국내 이동통신 서비스 시장은 급속하게 발전해왔다. 이러한 성장에 맞춰 WCDMA 서비스가 중요한 성장 동력으로 기대했으나 해외에 비해 국내 보급률은 더딘 실정이다. 하지만 HSDPA의 상용화가 이루어지면서 정체된 WCDMA 단말기의 수요를 이끌 것으로 예상된다. 따라서 신규 WCDMA 서비스의 수요를 예측하고 그에 맞는 새로운 이동통신 사업 전략을 세우는 것이 필요할 것이다. 본 논문은 이동통신 단말기의 가격과 성능에 따른 소비자의 구매 효과를 반영하고, 변형된 Lotka-Volterra 예측 모형을 개발하여 향후 WCDMA 서비스 가입자를 예측하였다.

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Perceptional Change of a New Product, DMB Phone

  • Kim, Ju-Young;Ko, Deok-Im
    • 마케팅과학연구
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    • 제18권3호
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    • pp.59-88
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    • 2008
  • Digital Convergence means integration between industry, technology, and contents, and in marketing, it usually comes with creation of new types of product and service under the base of digital technology as digitalization progress in electro-communication industries including telecommunication, home appliance, and computer industries. One can see digital convergence not only in instruments such as PC, AV appliances, cellular phone, but also in contents, network, service that are required in production, modification, distribution, re-production of information. Convergence in contents started around 1990. Convergence in network and service begins as broadcasting and telecommunication integrates and DMB(digital multimedia broadcasting), born in May, 2005 is the symbolic icon in this trend. There are some positive and negative expectations about DMB. The reason why two opposite expectations exist is that DMB does not come out from customer's need but from technology development. Therefore, customers might have hard time to interpret the real meaning of DMB. Time is quite critical to a high tech product, like DMB because another product with same function from different technology can replace the existing product within short period of time. If DMB does not positioning well to customer's mind quickly, another products like Wibro, IPTV, or HSPDA could replace it before it even spreads out. Therefore, positioning strategy is critical for success of DMB product. To make correct positioning strategy, one needs to understand how consumer interprets DMB and how consumer's interpretation can be changed via communication strategy. In this study, we try to investigate how consumer perceives a new product, like DMB and how AD strategy change consumer's perception. More specifically, the paper segment consumers into sub-groups based on their DMB perceptions and compare their characteristics in order to understand how they perceive DMB. And, expose them different printed ADs that have messages guiding consumer think DMB in specific ways, either cellular phone or personal TV. Research Question 1: Segment consumers according to perceptions about DMB and compare characteristics of segmentations. Research Question 2: Compare perceptions about DMB after AD that induces categorization of DMB in direction for each segment. If one understand and predict a direction in which consumer perceive a new product, firm can select target customers easily. We segment consumers according to their perception and analyze characteristics in order to find some variables that can influence perceptions, like prior experience, usage, or habit. And then, marketing people can use this variables to identify target customers and predict their perceptions. If one knows how customer's perception is changed via AD message, communication strategy could be constructed properly. Specially, information from segmented customers helps to develop efficient AD strategy for segment who has prior perception. Research framework consists of two measurements and one treatment, O1 X O2. First observation is for collecting information about consumer's perception and their characteristics. Based on first observation, the paper segment consumers into two groups, one group perceives DMB similar to Cellular phone and the other group perceives DMB similar to TV. And compare characteristics of two segments in order to find reason why they perceive DMB differently. Next, we expose two kinds of AD to subjects. One AD describes DMB as Cellular phone and the other Ad describes DMB as personal TV. When two ADs are exposed to subjects, consumers don't know their prior perception of DMB, in other words, which subject belongs 'similar-to-Cellular phone' segment or 'similar-to-TV' segment? However, we analyze the AD's effect differently for each segment. In research design, final observation is for investigating AD effect. Perception before AD is compared with perception after AD. Comparisons are made for each segment and for each AD. For the segment who perceives DMB similar to TV, AD that describes DMB as cellular phone could change the prior perception. And AD that describes DMB as personal TV, could enforce the prior perception. For data collection, subjects are selected from undergraduate students because they have basic knowledge about most digital equipments and have open attitude about a new product and media. Total number of subjects is 240. In order to measure perception about DMB, we use indirect measurement, comparison with other similar digital products. To select similar digital products, we pre-survey students and then finally select PDA, Car-TV, Cellular Phone, MP3 player, TV, and PSP. Quasi experiment is done at several classes under instructor's allowance. After brief introduction, prior knowledge, awareness, and usage about DMB as well as other digital instruments is asked and their similarities and perceived characteristics are measured. And then, two kinds of manipulated color-printed AD are distributed and similarities and perceived characteristics for DMB are re-measured. Finally purchase intension, AD attitude, manipulation check, and demographic variables are asked. Subjects are given small gift for participation. Stimuli are color-printed advertising. Their actual size is A4 and made after several pre-test from AD professionals and students. As results, consumers are segmented into two subgroups based on their perceptions of DMB. Similarity measure between DMB and cellular phone and similarity measure between DMB and TV are used to classify consumers. If subject whose first measure is less than the second measure, she is classified into segment A and segment A is characterized as they perceive DMB like TV. Otherwise, they are classified as segment B, who perceives DMB like cellular phone. Discriminant analysis on these groups with their characteristics of usage and attitude shows that Segment A knows much about DMB and uses a lot of digital instrument. Segment B, who thinks DMB as cellular phone doesn't know well about DMB and not familiar with other digital instruments. So, consumers with higher knowledge perceive DMB similar to TV because launching DMB advertising lead consumer think DMB as TV. Consumers with less interest on digital products don't know well about DMB AD and then think DMB as cellular phone. In order to investigate perceptions of DMB as well as other digital instruments, we apply Proxscal analysis, Multidimensional Scaling technique at SPSS statistical package. At first step, subjects are presented 21 pairs of 7 digital instruments and evaluate similarity judgments on 7 point scale. And for each segment, their similarity judgments are averaged and similarity matrix is made. Secondly, Proxscal analysis of segment A and B are done. At third stage, get similarity judgment between DMB and other digital instruments after AD exposure. Lastly, similarity judgments of group A-1, A-2, B-1, and B-2 are named as 'after DMB' and put them into matrix made at the first stage. Then apply Proxscal analysis on these matrixes and check the positional difference of DMB and after DMB. The results show that map of segment A, who perceives DMB similar as TV, shows that DMB position closer to TV than to Cellular phone as expected. Map of segment B, who perceive DMB similar as cellular phone shows that DMB position closer to Cellular phone than to TV as expected. Stress value and R-square is acceptable. And, change results after stimuli, manipulated Advertising show that AD makes DMB perception bent toward Cellular phone when Cellular phone-like AD is exposed, and that DMB positioning move towards Car-TV which is more personalized one when TV-like AD is exposed. It is true for both segment, A and B, consistently. Furthermore, the paper apply correspondence analysis to the same data and find almost the same results. The paper answers two main research questions. The first one is that perception about a new product is made mainly from prior experience. And the second one is that AD is effective in changing and enforcing perception. In addition to above, we extend perception change to purchase intention. Purchase intention is high when AD enforces original perception. AD that shows DMB like TV makes worst intention. This paper has limitations and issues to be pursed in near future. Methodologically, current methodology can't provide statistical test on the perceptual change, since classical MDS models, like Proxscal and correspondence analysis are not probability models. So, a new probability MDS model for testing hypothesis about configuration needs to be developed. Next, advertising message needs to be developed more rigorously from theoretical and managerial perspective. Also experimental procedure could be improved for more realistic data collection. For example, web-based experiment and real product stimuli and multimedia presentation could be employed. Or, one can display products together in simulated shop. In addition, demand and social desirability threats of internal validity could influence on the results. In order to handle the threats, results of the model-intended advertising and other "pseudo" advertising could be compared. Furthermore, one can try various level of innovativeness in order to check whether it make any different results (cf. Moon 2006). In addition, if one can create hypothetical product that is really innovative and new for research, it helps to make a vacant impression status and then to study how to form impression in more rigorous way.

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