• Title/Summary/Keyword: Variable selection

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Evaluation of Target Position's Accuracy in 2D-3D Matching using Rando Phantom (인체팬톰을 이용한 2D-3D 정합시 타켓위치의 정확성 평가)

  • Jang, Eun-Sung;Kang, Soo-Man;Lee, Chul-Soo
    • The Journal of Korean Society for Radiation Therapy
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    • v.21 no.1
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    • pp.33-39
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    • 2009
  • Purpose: The aim of this study is to compare patient's body posture and its position at the time of simulation with one at the treatment room using On-board Imaging (OBI) and CT (CBCT). The detected offsets are compared with position errors of Rando Phantom that are practically applied. After that, Rando Phantom's position is selected by moving couch based on detected deviations. In addition, the errors between real measured values of Rando Phantom position and theoretical ones is compared. And we will evaluate target position's accuracy of KV X-ray imaging's 2D and CBCT's 3D one. Materials and Methods: Using the Rando Phantom (Alderson Research Laboratories Inc. Stanford. CT, USA) which simulated human body's internal structure, we will set up Rando Phantom on the treatment couch after implementing simulation and RTP according to the same ways as the real radioactive treatment. We tested Rando Phantom that are assumed to have accurate position with different 3 methods. We measured setup errors on the axis of X, Y and Z, and got mean standard deviation errors by repeating tests 10 times on each tests. Results: The difference between mean detection error and standard deviation are as follows; lateral 0.4+/-0.3 mm, longitudinal 0.6+/-0.5 mm, vertical 0.4+/-0.2 mm which all within 0~10 mm. The couch shift variable after positioning that are comparable to residual errors are 0.3+/-0.1, 0.5+/-0.1, and 0.3+/-0.1 mm. The mean detection errors by longitudinal shift between 20~40 mm are 0.4+/-0.3 in lateral, 0.6+/-0.5 in longitudinal, 0.5+/-0.3 in vertical direction. The detection errors are all within range of 0.3~0.5 mm. Residual errors are within 0.2~0.5 mm. Each values are mean values based on 3 tests. Conclusion: Phantom is based on treatment couch shift and error within the average 5mm can be gained by the diminution detected by image registration based on OBI and CBCT. Therefore, the selection of target position which depends on OBI and CBCT could be considered as useful.

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Comparison of palatal bone thickness between 3D model and lateral cephalometric radiograph (성인 구개부 측모두부계측방사선 사진과 3D model의 골두께 비교)

  • Jang, Min-Guk;Lee, Jin-Woo;Cha, Kyung-Suk;Chung, Dong-Hwa;Lee, Sang-Min
    • The korean journal of orthodontics
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    • v.41 no.5
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    • pp.312-323
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    • 2011
  • Objective: This study compared the bone thickness of the palate between lateral cephalogram and 3D model measurements. Methods: The subjects consisted of 30 adults (15 men,15 women) with a normal skeletal pattern and occlusion. The CT images were transformed to a 3D model, and were compared with the cephalometric image. Descriptive statistics for each variable were calculated. Results: In the 3D CT model, the mid-palatal area was the thickest part. It became thinner as the palate tapered laterally. In the male group, the thinnest portion was positioned 6 mm away from the mid-palate, while in the female group the thinnest portion was 8mm away from the mid-palate. Correlation analysis between the lateral cephalometric and 3D CT model revealed a significant correlation except in the mid palatal area and the area 2 mm lateral to the mid-palate in men, whereas there was a significant relationship in every area in the women. In both men and women, the highest correlation appeared in the area 8 mm lateral to the mid palate. Conclusions: Using regression analysis, an actual prediction of the bone thickness between the measured bone thickness of the lateral cephalometric radiograph and 3D model was made. This will provide useful information for mini-implant length selection when inserting into the palate.

Study of Dental Hygienist's Stress Degree and Adaptation Method (치과위생사의 스트레스 정도와 적응 방법에 관한 연구)

  • Gwon, Mi-Young;Jung, Mee-Hee
    • Journal of dental hygiene science
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    • v.4 no.3
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    • pp.133-140
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    • 2004
  • It examines closely the occupation characteristic primary factor which the dentistry hygienic company field which is working to presence at a sickbed is undergoing the degree and from the research which it sees and it grasps the adaptation method against it gropes bitterly with development of the dentistry hygienic company individual to join in, it contributed in dentistry medical treatment service quality improvement and the research which tries to sleep it attempted. Currently the dentistry hygiene which works from Seoul and the condition area subject matter dentist unit, the dentistry hospital and the general hospital dentistry back it did in the object which it will burn. 116 issues which become frequency in question 120 it used SPSS 10.0 and it analyzed. Result of this study is as following. (1) Was expose that stress degree by factor feels about commonness on the whole, and angle prospects and support connection stress at company were the biggest item by item, and appeared as on the other hand relation connection stress with patient is the smallest. (2) Stress that stress degree by each receives in case of there are a lot of other businesses to characteristic businesses except appeared highest. On the other hand, was expose that feel the lowest stress degree an item that other a type of occupation and discord are. (3) 'Do action of that throw goods or closes the door bump' appeared article highest by short term adaptation method about stress, and 'Think and gives up by fate' appeared highest by special skill adaptation method. Short term adaptation method appeared high than special skill adaptation method on the whole but the difference appeared as is very small. (4) Stress degree comparison by general special quality was shown difference that stress by only dental hygiene administration of justice selection motive keeps in mind. (5) All of the result that compare short term, long term adaptation method about stress that feel new dental higienist apple career dental higienist same difference be, but displayed high result in same munhang. (6) Was expose that difference that keep in mind from all arguments in comparison of short term adaptation method by general special quality does not exist, on the other hand, comparison of long-term adaptation method displayed result that religion among only variable keeps in mind statistically.

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The Clinical Efficacy of Uvulopalatopharyngoplasty in the Treatment of Obstructive Sleep Apnea Syndrome (폐쇄성 수면 무호흡 증후군 치료에서 구개수구개인두성형술의 임상적 유용성)

  • Moon, Hwa-Sik;Choi, Young-Mee;Park, Young-Hak;Kim, Young-Kyoon;Kim, Kwan-Hyoung;Song, Jeong-Sup;Park, Sung-Hak
    • Tuberculosis and Respiratory Diseases
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    • v.44 no.6
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    • pp.1366-1381
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    • 1997
  • Background : Uvulopalatopharyngoplasty(UPPP) has become the most common surgical treatment for obstructive sleep apnea syndrome(OSAS). However, the results of this therapeutic modality have been quite variable with successful results by several authors and poor results by others. Until recently, in Korea, there is only a few reports about the clinical efficacy of UPPP. A prospective study was undertaken to evaluate the effectiveness and complications of UPPP. Method : Twenty-six OSAS patients who had undergone UPPP with preoperative and postoperative polysomnographic studies were included in this study. Two definitions of surgical success were used. The responder was defined, using a conventional criteria, as a 50% or more reduction in apnea index(AI) or apneahypopnea index(AHI) after UPPP, or a postoperative AI of <10 or AHI of <20. The initial cure was defined, using our own criteria, as a postoperative AI of <5 or AHI of <10. Complications were categorized in two groups : early(disorders during the first 10 postoperative days) and late. Results : Eighteen patients(69.2%) were responders, and ten patients(38.5%) were considered as initial cure. On the other hand, in five patients (19.2%), postoperative polysomnographic data demonstrated deterioration compared with preoperative data. Reduction rate of AI or AHI following UPPP was not significantly related to the preoperative body mass index, AI or AHI. There was no significant change of sleep architecture before and after UPPP in responder and initial cure groups. Early complications such as pain, dyspnea, bleeding, nasal reflux, dysphagia or wound disruption were observed in all patients. Late complications such as nasal reflux, voice change, dysphagia, loss of taste, pharyngeal dryness or foreign body sensation were discovered in 22 patients (84.6%). However, all early and late complications were of minor importance. Conclusion : The response to UPPP was favorable in approximately 70% of OSAS patient. However, the initial Cure rate of UPPP was relatively low. We suggest that selection of more appropriate surgical candidates and adequate surgical protocol is necessary to obtain a more successful result with UPPP.

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Control of Diatrype stigma Occurred on the Bed-log of Shiitake Using Wood Vinegar, Plant Extracts and Fungicides (목초액, 식물추출물 및 살균제를 이용한 표고골목해균인 주홍꼬리버섯 방제)

  • Bak, Won-Chull;Lee, Bong-Hun;Ka, Kang-Hyeon;Cho, Tae-Soo;Lee, Hak-Joo;Lee, Sung-Suk;Kim, Myung-Kil;Cha, Byeong-Jin
    • The Korean Journal of Mycology
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    • v.34 no.1
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    • pp.22-28
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    • 2006
  • Attempts were made to control Diatrype stigma occurred on the bed-log of Shiitake using wood vinegar, Pinus koraiensis extract, Piper nigrum extract, and fungicides. Mycelial growth of D. stigma was inhibited completely at 35,000 ppm and no ascospore germinated at 25,000 ppm wood vinegar. Inhibition rates of Pinus koraiensis extract (200 ppm), and Piper nigrum extract (1,000 ppm) to ascospore germination were 98.9% and 95.9%, respectively. In fungicide selection, minimum inhibitory concentration (MIC) of benomyl, carbendazim, and thiabendazole ranged $0{\sim}0.4\;{\mu}g\;a.i/m{\ell}$. Difenoconazole at $0.08\;{\mu}g\;a.i/m{\ell}$ inhibited 98.9% of ascospore germination. Inhibition efficacy of fungicides was not highly variable among the low-, middle-, and high-temperature type strains of shiitake. Benomyl, carbendazim, thiabendazole and thiophanate-methyl could not suppress the mycelial growth of Shiitake. Tebuconazole at $0.4\;{\mu}g\;a.i/m{\ell}$ suppressed 80% of the mycelial growth and it was the highest inhibition rate among the fungicides. In field trials, wood vinegar, Pinus koraiensis extract, Piper nigrum extract, and fungicides were sprayed on the bed-logs before or after D. stigma produced pycnidia. Wood vinegar at 150,000 ppm concentration, showed control effect of 72.7% in the treatment before pycnidiospore formation. On the other hand, 70,000 ppm wood vinegar and 1,000 ppm of thiophanate-methyl showed control effects of 58.1% and 52.3% in the treatment after pycnidiospore formation.

Bioinformatic Analysis of the Canine Genes Related to Phenotypes for the Working Dogs (특수 목적견으로서의 품성 및 능력 관련 유전자들에 관한 생물정보학적 분석)

  • Kwon, Yun-Jeong;Eo, Jungwoo;Choi, Bong-Hwan;Choi, Yuri;Gim, Jeong-An;Kim, Dahee;Kim, Tae-Hun;Seong, Hwan-Hoo;Kim, Heui-Soo
    • Journal of Life Science
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    • v.23 no.11
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    • pp.1325-1335
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    • 2013
  • Working dogs, such as rescue dogs, military watch dogs, guide dogs, and search dogs, are selected by in-training examination of desired traits, including concentration, possessiveness, and boldness. In recent years, genetic information has been considered to be an important factor for the outstanding abilities of working dogs. To characterize the molecular features of the canine genes related to phenotypes for working dogs, we investigated the 24 previously reported genes (AR, BDNF, DAT, DBH, DGCR2, DRD4, MAOA, MAOB, SLC6A4, TH, TPH2, IFT88, KCNA3, TBR2, TRKB, ACE, GNB1, MSTN, PLCL1, SLC25A22, WFIKKN2, APOE, GRIN2B, and PIK3CG) that were categorized to personality, olfactory sense, and athletic/learning ability. We analyzed the chromosomal location, gene-gene interactions, Gene Ontology, and expression patterns of these genes using bioinformatic tools. In addition, variable numbers of tandem repeat (VNTR) or microsatellite (MS) polymorphism in the AR, MAOA, MAOB, TH, DAT, DBH, and DRD4 genes were reviewed. Taken together, we suggest that the genetic background of the canine genes associated with various working dog behaviors and skill performance attributes could be used for proper selection of superior working dogs.

Extraction of Essential Design Elements for Urban Parks - Based on the Analysis of 2017 Satisfaction Survey of Park Use in Seoul - (도시공원의 필수 설계요소 추출 - 2017년 서울시 공원이용 만족도 조사의 결과 분석을 바탕으로 -)

  • Lee, Jae Ho;Kim, Soonki
    • Journal of the Korean Institute of Landscape Architecture
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    • v.46 no.6
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    • pp.41-48
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    • 2018
  • The aim of this study is to provide foundational knowledge of how to enhance the user satisfaction of urban parks. The study seeks to identify essential factors that influence user satisfaction and to provide better design strategies for future park design as well as the reorganization of existing ones. To measure user satisfaction, this study used factor analysis to extract essential factors - facility conditions, landscape and scenery, safety, and kindness - by using data from a survey conducted by the city of Seoul in 2017. We then used a regression analysis to infer causal relationships between the independent variables and the dependent variables (user satisfaction). The results revealed that the most significantly and positively related variable to user satisfaction in urban parks was safety (${\beta}=0.276$, p<.000), followed by landscape and scenery (${\beta}=0.230$, p<.000), facility conditions (${\beta}=0.215$, p<.000), and kindness (${\beta}=0.208$, p<.000). The results indicate that, for future urban park designs, planners and designers should prioritize the issues of safety by adopting crime prevention through environmental design (CPTED). In addition, planners and designers of future park designs should heavily weigh the selection and provision of relevant facilities for the intended use as well as well-arranged and well-managed plants and trees. Based on the results of IPA analysis, the most urgent improvement elements appeared to be the factor of kindness; however, the impact of kindness influencing user satisfaction was less important than that of safety and landscape and scenery in the urban park design processes. This study demonstrates that to maximize the user satisfaction of the urban park design processes and to provide more valuable spaces for users, it is necessary to secure park safety and to create well-composed landscape and scenery. Future research should provide more detailed and specified urban park design strategies corresponding with the importance of the factors identified in this study.

An exploration of the relationship between crime/victim characteristics and the victim's criminal damages: Variable selection based on random forest algorithm (범죄 및 피해자 특성과 범죄피해 내용의 관계 탐색: 랜덤포레스트 알고리즘에 기초한 변인선택)

  • Han, Yuhwa;Lee, Wooyeol
    • Korean Journal of Forensic Psychology
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    • v.13 no.2
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    • pp.121-145
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    • 2022
  • The current study applied the random forest algorithm to Korean crime victim survey data collected biennially between 2010 and 2018 to explore the relationship between crime/victim characteristics and the victim's criminal damages. A total of 3,080 cases including gender, age (life cycle stage), type of crime, perpetrator acquisition, repeated victimization, psychological damage (depression, isolation, extreme fear, somatic symptoms, interpersonal problems, moving out to avoid people, suicidal impulses, suicide attempts), and emotional changes after victimization (changes in self-protection confidence, self-esteem, confidence in others, confidence in legal institutions, and respect for Korean legal system/law) were analyzed. Considering the features of data that are difficult to apply traditional statistical techniques, this study implemented random forest algorithms to predict crime and victim characteristics using the victim's criminal damages (psychological damage and emotional change) and selected good predictors using VSURF function in VSURF package for R. As a result of the analysis, it was confirmed that the relationship between the type of crime and depression, extreme fear, somatic symptoms, and interpersonal problems, between perpetrator acquisition and somatic symptoms and interpersonal problems, and between repeated victimization and changes in respect for Korean legal system/law. Gender and life cycle stage (youth/adult/elderly) were found to be related to extreme fear and changes in self-protection confidence, respectively. However, more empirical evidence should be aggregated to explain the results as meaningful. The results of this study suggest that it is necessary to enhance the experts' knowledge and educate them on cases about the relationship between crime/victim characteristics and criminal damage. Strengthening their interview strategy and knowledge about law/rules were also needed to increase the effectiveness of the Korean victim assessment system.

ESG Variables Selection for Container Port Using WNA (워드네트워크 분석을 활용한 컨테이너부두 ESG 변수 선정)

  • Shin, Jong-Bum;Kim, Kyung-Tae;Kim, Hyun-Deok
    • Journal of Korea Port Economic Association
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    • v.39 no.2
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    • pp.15-23
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    • 2023
  • In a situation where the necessity and importance of ESG management is increasing recently, it is judged that selecting important ESG-related variables for container terminals, which are the bases of export and import logistics, among various variables of ESG evaluation agencies will help to establish ESG management strategies for container terminals which led us to proceed with this study. The results of word network analysis are summarized as follows. The weighed degree, that is, the AWD of Environmental management(E) variables, is obtained in the order of Environmental Protection Investment(54), Environmental Awareness Education(45), Work Team Structure(31), Environmental certification(32). Page Ranks, the order of centrality and connectivity index is Environmental Awareness Education(0.0765), Employee Engagement(0.0765), Environmental Protection Investment(0.0761), Work Team Composition(0.0761), and Environmental certification(0.0761). The AWD(Average Weighed Degree) of the Social Responsibility Management(S) variables, followed by Protecting workers' human rights and contributing to local communities(68), Safety Education(63), Safety certification(59), and Responding to infectious diseases(40). Orders by Page Ranks, centrality and connectivity Index, are Protecting workers' human rights and contributing to local communities(0.165), Safety Education(0.153), Safety Certification(0.144) and Responding to infectious diseases(0.102). The AWD of Governance and Ethical management(G) variables, followed by Anti-corruption(27), Transparent management(24), Mutual cooperation between stakeholders(19), and Sustainability reporting(9). Page Ranks, the order of centrality and connectivity index is the Anti Corruption(0.241), Transparent management(0.216), Mutual cooperation between stakeholders(0.174), Directors' roles and responsibilities(0.105), Shareholder protection(0.097) and Sustainability Report(0.096).

The Effect of the Gap between College Students' Perception of the Importance of Coffee Shops and Their Satisfaction after Patronizing Coffee Shops on Their Purchasing Behavior (대전원교학생대가배점중요성적감지화타문광고가배점지후적만의도지간적차거대타문구매행위적영향(大专院校学生对咖啡店重要性的感知和他们光顾咖啡店之后的满意度之间的差距对他们购买行为的影响))

  • Lee, Won-Ok
    • Journal of Global Scholars of Marketing Science
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    • v.19 no.4
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    • pp.1-10
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    • 2009
  • The purpose of this study was to categorize the gap between coffee shop 'importance' (as perceived by customers before patronizing the coffee shop) and 'satisfaction' (perception of customers after patronizing the coffee shop) as positive or negative and to analyze the effect of these gaps on purchasing behavior. To do this, I used the gap between importance and satisfaction regarding the choice of a coffee shop as the explanatory variable and performed an empirical analysis of the direction and size of the effect of the gap on purchasing behavior (overall satisfaction, willingness-to-revisit) by applying the Ordered Probit Model (OPM). A previous study that used IPA to evaluate the effects of gaps estimated the direction and size of a quadrant but failed to analyze the effect of gaps on customers. In this study, I evaluated the effects of positive and negative gaps on customer satisfaction and willingness-to-revisit. Using OPM, I quantified the effect of positive and negative gaps on overall customer satisfaction and willingness-to-revisit. Per-head expenditure, frequency of visits, and coffee-purchasing place had the most positive effects on overall customer satisfaction. Frequency of visits, followed by per-head expenditure and then coffee-purchasing place, had the most positive impact on willingness-to-visit. Thus per-head expenditure and frequency of visits had the greatest positive effects on overall satisfaction and willingness-to-revisit. This finding implies that the higher the actual satisfaction (gap) of customers who spend KRW5,000 or more once or more per week at coffee shops is, the higher their overall satisfaction and willingness-to-revisit are. Despite the fact that economical efficiency had a significant effect on overall satisfaction and willingness-to-revisit, college and university students still use coffee shops and are willing to spend KRW5,000 because they do not only purchase coffee as a product itself, but use the coffee shop for other activities, such as working, meeting friends, or relaxing. College and university students also access the Internet in coffee shops via personal laptops, watch movies, and study; thus, coffee shops should provide their customers with the appropriate facilities and services. The fact that a positive gap for coffee shop brand had a positive effect on willingness-to-revisit implies that the higher the level of customer satisfaction, the greater the willingness-to-revisit. A negative gap for this factor, on the other hand, implies that the lower the level of customer satisfaction, the lower the willingness-to-revisit. Thus, the brand factor has a comparatively greater effect on satisfaction than the other factors evaluated in this study. Given that the domestic coffee culture is becoming more upscale and college/university students are sensitive to this trend, students are attentive to brands. In most upscale coffee shops in Korea, the outer wall is built out of glass that can be opened, the interiors are exotic with an open kitchen. These upscale coffee shops function as landmarks and match the taste of college/university students. Coffee shops in Korea have become a cultural brand. To make customers feel that coffee shops are upscale, good quality establishments and measures to provide better services in terms of brand factor should be instituted. The intensified competition among coffee shop brands in Korea as a result of the booming industry indicates that provision of additional services is needed to differentiate competitors. These customers can also use a scanner free of charge. Another strategy that can be used to boost brands could be to provide and operate a seminar room for seminars and group study. If coffee shops adopt these types of strategies, college/university students would be more likely to consider the expenses they incur worthwhile and, subsequently, they would be more likely to be satisfied with the brands of these coffee shops, with an associated increase in their willingness-to-revisit. Gender and study year had the most negative effects on overall satisfaction and willingness-to-revisit. Female students were more likely to be satisfied and be willing to return than male students, and third and fourth-year students were more likely to be satisfied and willing-to-return than first or second-year students. Students who drink coffee, read books, and use laptops alone at coffee shops are easily noticeable. High-grade students tend to visit coffee shops alone in order to use their time efficiently for self-development and to find jobs. The economical efficiency factor had the greatest effect on overall satisfaction and willingness-to-revisit in terms of a positive gap. The higher the actual satisfaction (gap) of students with the price of the coffee, the greater their overall satisfaction and willingness-to-revisit. Economical efficiency with a negative gap had a negative effect on willingness-to-revisit, which implies that a less negative gap will result in a greater willingness-to-revisit. Amid worsening market conditions, coffee shops located around colleges/universities are using strategies, such as a point or membership card, strategic alliances with credit-card companies, development of a set menu or seasonal menu, and free coffee-shot services to increase their competitive edge. Product power also had a negative effect in terms of a negative gap, which indicates that a higher negative gap will result in a lower willingness-to-revisit. Because there are many more customers that enjoy coffee in this decade, as compared to previous decades, the new generation of customers, namely college/university students, want various menu items in addition to coffee, and coffee shops should, therefore, add side menu items, such as waffles, rice cakes, cakes, sandwiches, and salads. For example, Starbucks Korea is making efforts to enhance product power by selling rice cakes flavored in strawberry, wormwood, and pumpkin, and providing coffee or cream free of charge. In summary, coffee shops should focus on increasing their economical efficiency, brand, and product power to enhance the satisfaction of college/university students. Because shops adjacent to colleges or universities enjoy a locational advantage, providing differentiated services in terms of economical efficiency, brand, and product power, is likely to increase customer satisfaction and return visits. Coffee shop brands should, therefore, be innovative and embrace change to meet their customers' desires. Because this study only targeted college/university students in Seoul, comparative studies targeting diverse regions and age groups are required to generalize the findings and recommendations of this study.

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