• 서비스연구
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• 제14권2호
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• pp.1-17
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• 2024

온라인 배너 광고 산업에서는 일반적으로 복수의 배너 대안이 제작된다. 이때 중요한 의사결정은 어떤 광고 배너 대안을 선택해서 고객에게 노출하느냐 하는 것이다. 각 배너 대안을 고객이 클릭할 확률을 미리 알 수 없기 때문에 경영자는 실험적으로 여러 대안을 노출한 후, 고객의 클릭 여부에 따라 각 대안의 클릭 확률을 추정하며 최적의 대안을 찾아야 하고 이것은 온라인 광고와 관련된 강화학습 프로세스이다. 이 과정에서의 주요 의사결정 문제는 축적된 추정 클릭 확률 지식을 이용해서 최적의 대안을 노출하는 활용 전략과, 잠재적으로 더 우수한 대안을 찾기 위해 새로운 대안을 시도해보는 탐색 전략의 최적 균형점을 찾는 것이다. 본 연구는 구전효과와 대안의 수가 이러한 최적 탐색-활용 전략에 미치는 영향을 분석하였다. 이는 고객이 노출된 배너를 클릭하는 경우 관련 제품을 주위에 홍보하는 과정을 통해 광고 배너의 클릭률이 높아지는 구전효과를 온라인 광고 관련 강화학습에 추가하여 구현한 것이다. 분석을 위해 Multi-Armed Bandit 모형을 이용한 시뮬레이션 기법을 사용하였다. 분석 결과, 구전효과의 크기가 커지고 배너 대안의 수가 적을수록 광고 강화학습의 최적 탐색 수준이 높아지는 것이 관측되었다. 이는 구전효과에 의해 고객이 광고 배너를 클릭할 확률이 증가함에 따라 기존에 축적했던 추정 클릭률 지식의 가치가 낮아지고, 따라서 새로운 대안을 탐색하는 것의 가치가 증가하기 때문으로 분석되었다. 또한 광고 대안의 수가 작을 경우에는 구전효과 크기가 커질 때 최적 탐색 수준이 더 큰 폭으로 증가하는 경향을 발견하였다. 최근 온라인 구전으로 인해 구전효과의 영향이 커지는 시점에서 본 연구는 의미 있는 시사점을 제공한다.

• Radiation Oncology Journal
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• 제18권2호
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• pp.138-149
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• 2000

목적 : X-선 조사 후 이동원 염색체와 환형 염색체의 빈도가 피폭 선량과 비례하는지를 확인하고, X-선 조사시 선량률의 변화가 생물학적 선량 측정에 영향을 주는지를 찾아서 보정인자로 작용하는지를 알아보았다. 대상 및 방법 : 28세의 건강한 성인남자에서 2회에 걸쳐 각각 16 ml와 18 ml의 전혈을 정맥으로부터 무균채취하여 이미 해파린(heprin) 처리되어 있는 10 ml의 vacutainer (삼화공사, 한국)에 2 ml씩 분주하였다. 분주한 혈액 시료를 1개는 정상대조 군으로 16개는 실험 군으로 총 17개를 실험에 사용하였으며, 방사선 조사는 조사야 10${\times}$10 cm$^{2}$로 분당 240 cGy 의 일정한 선량률로 50, 100, 200, 300, 400, 600, 800 cGy의 선량을 각 1회 조사하였다. 나머지 9개의 실험 군은 동일한 선량(400 cGy)에서 선량률 변화만 주어 20, 40, 60, 80, 100, 160, 240, 320, 400 cGy/min의 각 선량률로 1회 조사하였다. 관찰 시 염색체의 개수가 46${\times}$2개 되는지 여부를 확인하고 또한 염색체의 밀도나 염색체 형태가 염색체 이상 빈도 확인에 적합한지 확인한 후 해당되는 경우에 한해서만 계측하였다. 각 표본에서 최소 50개의 림프구를 관찰하려고 하였다. 통계처리는 SPSS를 이용하여 평균값 비교와 회귀곡선의 기울기 값을 구하였다. 결과 : 방사선 조사된 림프구의 관찰된 총 수에 대한 염색체 이상을 가진 림프구의 비율(yield)은 선량이 50, 100, 200, 300, 400, 600, 800 cGy일 때 각각 0, 9, 20, 27, 55, 88, 100%이었다. 선량변화에 따른 염색체 이상(이동원 및 환형 염색체)의 평균빈도는 50, 100, 200, 300, 400, 500, 800 cGy일 때 각각 0.000, 0.093, 0.200, 0.354, 0.612, 2.040, 2.846이었다. 관찰된 총림프구에서 이동원 염색체와 환형 염색체의 빈도(Ydr)는 선량이 50, 100, 200, 300, 400, 600, m cGy일 때 각각 0.000, 0.093, 0.200, 0.364, 0.613, 2.040, 2.846이었다. 방사선량과 Ydr의 관계는 Ydr=$\alpha$D+$\beta$D$^{2}$에 의한 Liner-quadratic model을 따를 때 Ydr=0.188${\times}$10$^{-2}$ D/Gy+0.422${\times}$10$^{-4}$/Gy$^{2}$${\times}$D$^{2}$로 나타났다. 이동원 염색체와 환형 염색체 이상을 가지는 림프구에서 이동원 염색체와 환형 염색체의 빈도(Qdr)는 50, 100, 200, 300, 400, 600, 800의 선량일 때 각각 0.000, 1.000, 1.000, 1.333, 1.118, 2.318, 2.846 이었으며 이는 앞의 Ydr값으로부터 구한 값과 거의 일치하였다. 선량율을 각각 20, 40, 60, 80, 100, 160, 240, 320, 400 cGy/min으로 달리하여 총 선량을 400 cGy를 각각 조사했을 때 임파구에서 나타난 염색체이상(이동원, 환형, 무동원체단편 염색체)의 빈도의 차는 없었다. 결론 : 방사선의 급성 피폭에 의한 손상은 선량률에 의한 영향은 미미하며 대부분 피폭된 총 선량에 의해 좌우된다. 염색체 이상을 이용한 생물학적 선량측정방법은 피폭 선량이 증가함에 따라 비교적 규칙적으로 증가하므로 피폭 선량 측정을 위한 유용한 방법이라고 생각한다. 그러나 일회 피폭인 급성 피폭 시는 선량률 변화가 보정인자로써 작용하지는 않았다.

• 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.