• Title/Summary/Keyword: Model-based evaluation

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An Experimental Study on the Estimation Method of Overtopping Discharge at the Rubble Mound Breakwater Using Wave-Overtopping Height (월파고를 이용한 사석경사제의 월파량 산정방법에 관한 실험적 연구)

  • Dong-Hoon Yoo;Young-Chan Lee;Do-Sam Kim;Kwang-Ho Lee
    • Journal of Navigation and Port Research
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    • v.48 no.3
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    • pp.192-199
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    • 2024
  • Wave overtopping is a significant natural hazard that occurs in coastal areas, primarily driven by high waves, particularly those generated during typhoons, which can cause coastal flooding. The development of residential and commercial areas along the coast, driven by increasing social and economic demands, has led to a concentration of people and assets in these vulnerable areas. This, coupled with long-term sea level rise and an increase in typhoon frequency, has heightened the risk of coastal hazards. Traditionally, the evaluation of wave overtopping volumes has relied on directly measuring the collected volume of water that exceeds the crest height of structures through hydraulic model experiments. These experiments are averaged over a specific measurement period. However, in this study, we propose a new method for estimating individual wave overtopping volumes. We utilize the temporal variation of wave overtopping heights to develop an observation system that can quantitatively assess wave overtopping volumes in actual coastal areas. To test our method, we conducted hydraulic model experiments on rubble mound breakwaters, which are commonly installed along the Korean coast. We introduce wave overtopping discharge coefficients, assuming that the inundation velocity from the structure's crest is the long-wave velocity. We then predict overtopping volumes based on wave overtopping heights and compare and review the results with experimental data. The findings of our study confirm the feasibility of estimating wave overtopping volumes by applying the overtopping discharge coefficients derived in this study to wave overtopping heights.

A study on the feasibility analysis of the current flood season: a case study of the Yongdam Dam (현행 법정홍수기 타당성 검토 및 개선에 관한 연구: 용담댐 사례)

  • Lee, Jae Hwang;Kim, Gi Joo;Kim, Young-Oh
    • Journal of Korea Water Resources Association
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    • v.57 no.5
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    • pp.359-369
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    • 2024
  • Korea prepares for potential floods by designating June 21st to September 20th as the flood season. However, many dams in Korea have suffered from extreme floods caused by different climate patterns, as in the case of the longest consecutive rain of 54 days in the 2020's flood season. In this context, various studies have tried to develop novel methodologies to reduce flood damage, but no study has ever dealt with the validity of the current statutory flood season thus far. This study first checked the validity of the current flood season through the observation data in the 21st century and proved that the current flood season does not consider the effects of increasing precipitation trends and the changing regional rainfall characteristics. In order to deal with these limitations, this study suggested seven new alternative flood seasons in the research area. The rigid reservoir operation method (ROM) was used for reservoir simulation, and the long short-term memory (LSTM) model was used to derive predicted inflow. Finally, all alternatives were evaluated based on whether if they exceeded the design discharge of the dam and the design flood of the river. As a result, the floods in the shifted period were reduced by 0.068% and 0.33% in terms of frequency and duration, and the magnitude also decreased by 24.6%, respectively. During this period, the second evaluation method also demonstrated that flood decreased from four to two occurrences. As the result of this study, the authors expect a formal reassessment of the flood season to take place, which will ultimately lead to the preemptive flood response to changing precipitation patterns.

Factors Affecting Female College Students' Reproductive Health Information Seeking Behaviors on the Internet (여대생의 인터넷 생식건강정보 탐색에 영향을 미치는 요인 연구)

  • Hyunsoo Yoon;Sanghee Oh;Yeongmi Lee
    • Journal of the Korean Society for information Management
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    • v.41 no.1
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    • pp.389-409
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    • 2024
  • The purpose of this study is to identify the factors affecting female college students' behaviors in seeking reproductive health information on the Internet and to explore the relationships among these factors. Based on the Health Belief Model(HBM) and the Theory of Planned Behavior(TPB), perceived sensitivity, perceived severity, perceived benefit, perceived barriers, subjective norms, perceived behavioral control, and affective evaluation were defined as key factors, and the study was designed accordingly. An online survey was distributed to female college students in Seoul through the university student's online community, 'Everytime.' The results showed that the intention of female college students to seek reproductive health information via the Internet was associated with higher perceived sensitivity, perceived benefit, and subjective norms, and lower perceived barriers. There were statistically significant differences between groups in terms of sexual experiences, experience with reproductive system disorders, and the level of health interest. We believe that this research outcome will contribute to assessing the level of awareness regarding reproductive health among female college students, thereby aiding in the development of online health information literacy education or related service programs by university libraries, health institutions, and similar entities targeting female college students.

Comparison between village characteristics and habitat quality to application OECM in Nakdong-Jeongmaek (낙동정맥 내 OECM 적용 가능 지역 발굴을 위한 마을 특성과 서식지 질 비교)

  • Oh, Ju-Hyeong;Kim, Su-Jin;Kim, Tae-Su;Jang, Gab-Su;Jeon, Seong-Woo
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.26 no.6
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    • pp.51-65
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    • 2023
  • The Jeongmaeks are Korea's unique forest space recognition system that diverged from the Baekdudaegan. The Jeongmaeks are easily exposed to pressure because it is adjacent to the living area. Among them, Nakdong-Jeongmaek has high biodiversity, but damage is accelerating. According to the Convention on Biological Diversity (CBD) in 2022, the target is to expand the area of terrestrial and marine protected areas to 30% of national territory by 2030. As of September 2023, the area of terrestrial protected areas in South Korea is only 16.97% of the country's territory. This is due in part to the high proportion of private forests in the region, which makes it difficult to establish protected areas. Therefore, there is a need to establish Other Effective Area-based Conservation Measure (OECMs), which pursue complex and effective conservation that considers multiple values, as an alternative to protected areas. This study aims to identify areas suitable for OECM and to provide opinions on the establishment of appropriate management plans for each value using SOM and InVEST Habitat Quality model. This study evaluated the habitat quality of 206 villages located within 1km of the Nakdong-Jeongmaek and compared the characteristics of villages classified by SOM. As a result, the habitat quality was 0.867 for Tourism village (ClusterIV), 0.838 for Conservation village (ClusterVI), 0.835 for Mixed village (ClusterI), 0.796 for Production (ClusterV), 0.731 for Rural village (ClusterIII) and 0.625 for Urban village (ClusterII). When the distribution was identified through statistical analysis, the Kruskal-Wallis test showed that the distributions were not identical, with a p-value of 1.53e-08. Dunn's test showed a difference between Tourism, Conservation and Rural, Urban village. However, Mixed village was overestimated due to the lack of villages and the small area included in the study area. Moreover, Conservation village was somewhat under-evaluated in the analysis due to the use of a single weight for protected areas. It is necessary to perform additional reinforcement of the value evaluation of Jeongmaeks by conducting Forest Resource Survey and the National Natural Environment Survey. Therefore, we believe that sufficient validity for the establishment of OECMs in the Nakdong-Jeongmaek can be provided by addressing these limitations and conducting additional research.

The Determination of Trust in Franchisor-Franchisee Relationships in China (중국 프랜차이즈 시스템에서의 본부와 가맹점간 신뢰의 영향요인)

  • Shin, Geon-Cheol;Ma, Yaokun
    • Journal of Global Scholars of Marketing Science
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    • v.18 no.2
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    • pp.65-88
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    • 2008
  • Since the implementation of economic reforms in 1978, the Chinese economy grows rapidly at an average annul growth rate of 9% over the post two decades. Franchising has been widely recognized as an important source of entrepreneurial activity. Trust is important in that it facilitates relational exchanges by permits partners to transcend short-run inequities or risks to concentrate on long-term profits or gains. In the relationship between the franchisors and franchisees, trust has been described as an important source of competitive advantage. However, little research has been done on the factors affecting trust in Chinese franchisor-franchisee relationships. The purpose of this study is to investigate what factors affect the trust in the franchise system in China, and to provide guidelines and insights to franchisors which enter Chinese market. In this study, according to Morgan and Hunt (1994), trust is defined as the extending when one party has confidence in an exchange partner's reliability and integrity. We offered a conceptual model of the empirical study. The model shows that the factors affecting the trust include franchisor's supports, communication, satisfaction with previous outcome and conflict. We also suggested the franchisor's supports and communication like to enhance the franchisee's satisfaction with previous outcome, and the franchisor's supports, communication and he franchisee's satisfaction with previous outcome tend to decrease conflict. Before the formal study, a pretest involving exploratory interviews with owners from three franchisees was conducted to make sure the questionnaire was relevant and clear to the respondents. The data were collected using trained interviewers to carry out personal interviews with the aid of an unidentified, muti-page, structured questionnaire. The respondents comprised of owners, managers, and owner managers of franchisee-owned food service franchises located in Beijing, China. Even though a total of 256 potential franchises were initially contacted, the finally usable sample consisted of 125 respondents. As expected, the sampling method was successful in soliciting respondents with waried personal and firm characteristics. Self-administrated questionnaires were used for all measures. And established scales were used to measure the latent constructs in this study. The measures tapped the franchisees' perceptions of the relationship with the referent franchisor. Five-point Likert-type scales ranging from "strongly disagree" (=1) to "strongly agree" (=7) were used throughout the constructs (trust, eight items; support, five items; communication, four items; satisfaction, six items; conflict, three items). The reliability measurements traditionally employed, such as the Cronbach's alpha, were used. All the reliabilities were greater than.80. The proposed measurement model was estimated using SPSS 12.0 and AMOS 5.0 analysis package. We conducted A series of exploratory factor analyses and confirmatory factor analyses to assess the convergent validity, discriminant validity, and reliability. The results indicate reasonable overall fits between the model and the observed data. The overall fit of measurement model were $X^2$= 159.699, p=0.004, d.f. = 116, GFI =.879, NFI =.898, CFI =.969, IFI =.970, TLI =.959, RMR =.058. The results demonstrated that the data reasonably fitted the model. We also examined construct reliability and reliability and average variance extracted (AVE). The construct reliability of each construct was greater than.80 and the AVE of each construct was greater than.50. According to the analysis of Structure Equation Modeling (SEM), the results of path model indicated an adequate fit of the model: $X^2$= 142.126, p = 0.044, d.f. = 115, GFI =.892, NFI =.909, CFI =.981, IFI =.981, TLI =.974, RMR =.057. As hypothesized, the results showed that it is strategically important to establish trust in a franchise system, and the franchisor's supports, communication and satisfaction with previous outcome tend to reinforce franchisee's trust. The results also showed trust seems to decrease as the experience of conflict episodes increases. And we also noticed that franchisor's supports and communication tend to enhance the franchisee's satisfaction with previous outcome, and communication tend to decrease conflict. If the trust between the franchisor and franchisee can be established in a franchise system, franchising offers many benefits and reduces many costs. To manage a mutual trust of relationship with their franchisees, franchisor's should provide support effectively to their franchisees. Effective assistant services have direct effect on franchisees' satisfaction with previous outcome and trust in franchisor. Especially, franchise sales process, orientation, and training in the start-up period are key elements for success of the franchise system. Franchisor's support is an accumulated separate satisfaction evaluation with different kind of service provided by the franchisor. And providing support definitely can improve the trustworthy image of the franchisor. In the franchise system, conflicts of interests and exertions of different power sources are very common. The experience of conflict episodes seems to negatively relate to trust. Therefore, it is important to reduce the negative side of the relationship conflicts. Communication actually plays a broader role in reducing conflict and establish mutual trust in franchisor-franchisee relationship. And effective communication between franchisors and franchisees can improve franchisees' satisfaction toward the franchise system. As the diversification of Chinese markets, both franchisors and franchisees must keep the relevant, timely, and reliable communication. And it is very important to improve the quality of communication. Satisfaction with precious outcomes seems to positively relate to trust. Franchisors and franchisees that are highly satisfied with the previous outcomes that flow from their relationship will perceive their partner as advancing their goal achievement. Therefore, it is necessary for both franchisor and their franchisees to make the welfare of partner with effort. Little literature has focused on what factors affect the trust between franchisors and their franchisees in China. This study developed the hypotheses regarding the factors affecting trust in the transaction relationship. The results of data analysis supported the hypotheses strongly. There are certain limitations in this study. First, we may point out that some other factors missed in this study could be significantly important. Second, the context of this study, food service industry, limits its potential generalizability for all franchise systems. More studies in different categories of franchise system are needed to broaden its generalizability. Third, the model was tested empirically in a sample in Beijing, more empirical tests of the proposed model in other Chinese areas are needed. Finally, the analysis in this study was solely based on the perception of franchisees and the opinions of franchisors were not included.

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Analysis of Significance between SWMM Computer Simulation and Artificial Rainfall on Rainfall Runoff Delay Effects of Vegetation Unit-type LID System (식생유니트형 LID 시스템의 우수유출 지연효과에 대한 SWMM 전산모의와 인공강우 모니터링 간의 유의성 분석)

  • Kim, Tae-Han;Choi, Boo-Hun
    • Journal of the Korean Institute of Landscape Architecture
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    • v.48 no.3
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    • pp.34-44
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    • 2020
  • In order to suggest performance analysis directions of ecological components based on a vegetation-based LID system model, this study seeks to analyze the statistical significance between monitoring results by using SWMM computer simulation and rainfall and run-off simulation devices and provide basic data required for a preliminary system design. Also, the study aims to comprehensively review a vegetation-based LID system's soil, a vegetation model, and analysis plans, which were less addressed in previous studies, and suggest a performance quantification direction that could act as a substitute device-type LID system. After monitoring artificial rainfall for 40 minutes, the test group zone and the control group zone recorded maximum rainfall intensity of 142.91mm/hr. (n=3, sd=0.34) and 142.24mm/hr. (n=3, sd=0.90), respectively. Compared to a hyetograph, low rainfall intensity was re-produced in 10-minute and 50-minute sections, and high rainfall intensity was confirmed in 20-minute, 30-minute, and 40-minute sections. As for rainwater run-off delay effects, run-off intensity in the test group zone was reduced by 79.8% as it recorded 0.46mm/min at the 50-minute point when the run-off intensity was highest in the control group zone. In the case of computer simulation, run-off intensity in the test group zone was reduced by 99.1% as it recorded 0.05mm/min at the 50-minute point when the run-off intensity was highest. The maximum rainfall run-off intensity in the test group zone (Dv=30.35, NSE=0.36) recorded 0.77mm/min and 1.06mm/min in artificial rainfall monitoring and SWMM computer simulation, respectively, at the 70-minute point in both cases. Likewise, the control group zone (Dv=17.27, NSE=0.78) recorded 2.26mm/min and 2.38mm/min, respectively, at the 50-minutes point. Through statistical assessing the significance between the rainfall & run-off simulating systems and the SWMM computer simulations, this study was able to suggest a preliminary design direction for the rainwater run-off reduction performance of the LID system applied with single vegetation. Also, by comprehensively examining the LID system's soil and vegetation models, and analysis methods, this study was able to compile parameter quantification plans for vegetation and soil sectors that can be aligned with a preliminary design. However, physical variables were caused by the use of a single vegetation-based LID system, and follow-up studies are required on algorithms for calibrating the statistical significance between monitoring and computer simulation results.

Ship's Hull Fouling Management and In-Water Cleaning Techniques (선체부착생물관리와 수중제거기술)

  • Hyun, Bonggil;Jang, Pung-Guk;Shin, Kyoungsoon;Kang, Jung-Hoon;Jang, Min-Chul
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.24 no.6
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    • pp.785-795
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    • 2018
  • The International Maritime Organization (IMO) has recognized the risk of hull fouling and announced '2011 Guidelines for the control and management of ship's biofouling to minimize the transfer of invasive aquatic species'and is planning international regulations to enforce them in the future. In this study, to effectively respond to future international regulation, we introduce the case of leading countries related to management of hull fouling and also investigate environmental risk assessment techniques for in-water cleaning. Australia and New Zealand, the leading countries in hull fouling management, have established hull fouling regulations through biological and chemical risk assessment based on in-water cleaning scenarios. Most European countries without their government regulation have been found to perform in-water cleaning in accordance with the IMO's hull fouling regulations. In the Republic of Korea, there is no domestic law for hull fouling organisms, and only approximately 17 species of marine ecological disturbance organisms, are designated and managed under the Marine Ecosystem Law. Since in-water cleaning is accompanied by diffusion of alien species and release of chemical substances into aquatic environments, results from biological as well as chemical risk assessment are performed separately, and then evaluation of in-water cleaning permission is judged by combining these two results. Biological risk assessment created 40 codes of in-water cleaning scenarios, and calculated Risk Priority Number (RPN) scores based on key factors that affect intrusion of alien species during in-water cleaning. Chemical risk assessment was performed using the MAMPEC (Marine Antifoulant Model to Predict Environmental Concentrations), to determine PEC and PNEC values based on copper concentration released during in-water cleaning. Finally, if the PEC/PNEC ratio is >1, it means that chemical risk is high. Based on the assumption that the R/V EARDO ship performs in-water cleaning at Busan's Gamcheon Port, biological risk was estimated to be low due to the RPN value was <10,000, but the PEC/PNEC ratio was higher than 1, it was evaluated as impossible for in-water cleaning. Therefore, it will be necessary for the Republic of Korea to develop the in-water cleaning technology by referring to the case of leading countries and to establish domestic law of ship's hull fouling management, suitable for domestic harbors.

A Study on the ICAO international aviation safety policy, a change of paradigm and the government response to the direction (ICAO 국제항공안전정책 패러다임의 변화 분석과 우리나라 신국제항공안전정책 검토)

  • Chang, Man-Heui;Hwang, Ho-Won
    • The Korean Journal of Air & Space Law and Policy
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    • v.28 no.1
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    • pp.73-96
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    • 2013
  • ICAO's Universal Safety Oversight Audit Programme (USOAP) was initially launched in January 1995, in response to widespread concerns about the adequacy of aviation safety oversight around the world. The recent reduction in aircraft accidents and effective role that is evaluated on the basis of these results, and in 2013 the existing 'snapshot approach' to 'regular monitoring system (USOAP-Continuous Monitoring Approach)' was converted to. ICAO aviation safety assessment of the state in today's international community 'aviation safety credibility' as objective indicators to judge the enormous impact on the aviation industry, the state is not satisfactory, especially if the results of the evaluation and expansion of code-share airline ban, reduced international air transit passengers, including premium increases business and economic penalties should. In addition, ICAO implementation of the existing laws and regulations(Prescriptive Approach), but based on the Risk-based prevention model, Proactive Approach introduced the concept of aviation safety system, including international aviation safety policy has been to switch paradigms. This new ICAO international aviation safety policy also applies to the Government of the Republic of Korea in line with the aviation safey policies have changed. In particular, the systematic implementation of safety management for the existing laws and regulations in the center of the safety oversight system of risk-based introduction of the concept of proactive safety management, and According to international standards ICAO aviation service providers operate their own Safety Management System was set out in Aviation Law ever. In addition, the aviation safety is at the center of the field of the safety of aircraft operations and maintenance for the promotion is promoting various safety policies. This new paradigm shift in the international aviation safety policy in line with our state in the international community with the most exemplary aviation safety system firmly established itself as a model, the Government will strengthen the competitiveness of our aviation plans to support. To do this, the government, airlines, aviation officials try all the practical effect would be expected.

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Effects of Nutrition Education Program Based on Social Cognitive Theory for Low Sodium Consumption among Housewives Living in Certain Regions of Seoul (서울시 일부 지역 주부의 나트륨 섭취 감소를 위한 사회인지이론 기반의 영양 교육 프로그램의 적용 및 평가)

  • Baek, Jae Yeon;Yi, Hae-Yeon;Hwang, Ji-Yun;Kim, Kirang
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.46 no.10
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    • pp.1243-1252
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    • 2017
  • There are limited programs for low sodium intake based on the nutrition education model for housewives who cook family meals. The objective of this study was to evaluate the effects of model-based nutrition programs for low sodium intake among housewives residing in Seoul by incorporating social cognitive theory. A questionnaire survey before and after education was conducted on 140 housewives who participated in the 'Low Sodium Nutritional Education Program' delivered by a district public health center for 12 weeks from November 2015 to January 2016. The contents of the nutrition education program and program evaluation items were based on the action plans for 'Less Sodium Healthy Practice' suggested by the Ministry of Food and Drug Safety. The results show that program participants showed a lower preference for sodium, higher selection of low sodium dishes from restaurants or cafeteria if available, and increased awareness of the need of restaurants to serve low sodium dishes compared to before. In terms of behavioral changes, there were significant improvements in checking nutrition labeling and selection of foods with low sodium, use of low sodium food products, use of natural seasonings to reduce salt intake, and consumption of fast foods and processed foods. On the other hand, requesting less salty meals when ordering and introducing restaurants or cafeterias with healthy and low sodium menus turned out to be difficult to put into practice. In conclusion, the nutrition education program for sodium intake reduction for housewives was effective in increasing knowledge, environment recognition, and behaviors related to low sodium intake but not behaviors related to physical environmental factors. Therefore, further nutrition education programs and practices for sodium intake reduction should be comprehensively implemented with improvement of physical environments for low sodium intake.

Evaluation and Comparison of Effects of Air and Tomato Leaf Temperatures on the Population Dynamics of Greenhouse Whitefly (Trialeurodes vaporariorum) in Cherry Tomato Grown in Greenhouses (시설내 대기 온도와 방울토마토 잎 온도가 온실가루이(Trialeurodes vaporariorum)개체군 발달에 미치는 영향 비교)

  • Park, Jung-Joon;Park, Kuen-Woo;Shin, Key-Il;Cho, Ki-Jong
    • Horticultural Science & Technology
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    • v.29 no.5
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    • pp.420-432
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    • 2011
  • Population dynamics of greenhouse whitefly, Trialeurodes vaporariorum (Westwood), were modeled and simulated to compare the temperature effects of air and tomato leaf inside greenhouse using DYMEX model simulator (pre-programed module based simulation program developed by CSIRO, Australia). The DYMEX model simulator consisted of temperature dependent development and oviposition modules. The normalized cumulative frequency distributions of the developmental period for immature and oviposition frequency rate and survival rate for adult of greenhouse whitefly were fitted to two-parameter Weibull function. Leaf temperature on reversed side of cherry tomato leafs (Lycopersicon esculentum cv. Koko) was monitored according to three tomato plant positions (top, > 1.6 m above the ground level; middle, 0.9 - 1.2 m; bottom, 0.3 - 0.5 m) using an infrared temperature gun. Air temperature was monitored at same three positions using a Hobo self-contained temperature logger. The leaf temperatures from three plant positions were described as a function of the air temperatures with 3-parameter exponential and sigmoidal models. Data sets of observed air temperature and predicted leaf temperatures were prepared, and incorporated into the DYMEX simulator to compare the effects of air and leaf temperature on population dynamics of greenhouse whitefly. The number of greenhouse whitefly immatures was counted by visual inspection in three tomato plant positions to verify the performance of DYMEX simulation in cherry tomato greenhouse where air and leaf temperatures were monitored. The egg stage of greenhouse whitefly was not counted due to its small size. A significant positive correlation between the observed and the predicted numbers of immature and adults were found when the leaf temperatures were incorporated into DYMEX simulation, but no significant correlation was observed with the air temperatures. This study demonstrated that the population dynamics of greenhouse whitefly was affected greatly by the leaf temperatures, rather than air temperatures, and thus the leaf surface temperature should be considered for management of greenhouse whitefly in cherry tomato grown in greenhouses.