• Research in Plant Disease
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• v.13 no.1
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• pp.40-44
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• 2007

Powdery mildew of pepper is one of the most devastating diseases which is occurring all the year under greenhouse condition. In this study, control efficacy against powdery mildew was evaluated by mixed culture solutions of two chitinolytic bacteria, Lysobacter enzymogenenes strain C-3 and Chrornobacterium sp. strain C-61, cultivated in the chitin-supplemented medium. In all experiments, white powder on the reverse side of pepper leaves perfectly disappeared 3 days after application of mixed culture solutions. However, periods required for formation of new white powder on the same sites after application (control-lasting period) were largely differed according to environmental conditions. In particular, the control-lasting period was much longer when sprayed on 6 PM than 9 AM and especially, on rainy days than sunny days. This indicates that control efficacy of culture solution may be largely affected by environmental conditions after application. The undiluted culture solution resulted in a perfect control with control value more than 95% by application of 5-day-intervals under severely diseased field and 7-day-intervals under disease-started field. A ten-fold diluted product also showed control value more than 81% by application of the same method. These results suggest that this culture solution can be practically used to control powdery mildew disease in pepper plants.

• Korean Institute of Interior Design Journal
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• v.25 no.5
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• pp.82-92
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• 2016

This study aims to contribute to better understanding of the Baroque architect Francesco Borromini, and, as a consequence, of the Baroque period itself. Recognizing that historical studies have focused mainly on the architectural (i.e., formal) aspects of Borromini's work and largely neglected the technical (i.e., structural) issues, and that the relationship between the architectural and structural worlds in Borromini's activity has consequently never been studied in depth, this research set as its objective the study of this relationship, and has developed a comparative analysis of Borromini's attitude toward architectural problems and questions of tectonics. The investigation has been conducted on two meaningful case-studies in Rome: San Carlo alle Quattro Fontane and Sant'Ivo alla Sapienza. The analysis has highlighted a strong dichotomy between Borromini as an architectural designer and Borromini as a structural designer. While Borromini's design is experimental, innovative, and nonconformist, his structures are cautious, tested, and validated by trustworthy tradition. His unprejudiced use of constructive solutions from different historical periods, regions, and cultural areas allows the definition of his approach to tectonics as "constructive eclecticism." The analysis has also highlighted the independence between the architectural and structural aspects of his work, as the two do not interfere with or limit each other. The dichotomy between form and structure in Borromini's work may reflect the "theatrical" tendency of Baroque culture, where what is shown on the face is often different from what is hidden behind.

• Journal of Computing Science and Engineering
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• v.5 no.4
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• pp.316-323
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• 2011

Recently, Proxy Mobile IPv6 (PMIPv6) has received much attention as a mobility management protocol in next-generation all-IP mobile networks. While the current research related to PMIPv6 mainly focuses on providing efficient handovers for unicast-based applications, there has been relatively little interest in supporting multicast services with PMIPv6. To provide support for multicast services with PMIPv6, there are two alternative approaches called Mobile Access Gateway (MAG)-based subscription and Local Mobility Anchor (LMA)-based subscription. However, MAG-based subscription causes a large overhead for multicast joining and LMA-based subscription provides non-optimal multicast routing paths. The two approaches may also cause a high packet loss rate. In this paper, we propose an efficient PMIPv6-based multicast protocol that aims to provide an optimal delivery path for multicast data and to reduce handover delay and packet loss rate. Through simulation studies, we found that the proposed protocol outperforms existing multicast solutions for PMIPv6 in terms of end-to-end delay, service disruption period, and the number of lost packets during handovers.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.1
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• pp.105-113
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• 2017

Network externality can be defined as the effect that one user of a good or service has on the value of that product to other people. When a network externality is present, the value of a product or service is dependent on the number of others using it. There exist asymmetries in network externalities between the online and traditional offline marketing channels. Technological capabilities such as interactivity and real-time communications enable the creation of virtual communities. These user communities generate significant direct as well as indirect network externalities by creating added value through user ratings, reviews and feedback, which contributes to eliminate consumers' concern for buying products without the experience of 'touch and feel'. The offline channel offers much less scope for such community building, and consequently, almost no possibility for the creation of network externality. In this study, we analyze the effect of network externality on the competition between online and conventional offline marketing channels using game theory. To do this, we first set up a two-period game model to represent the competition between online and offline marketing channels under network externalities. Numerical analysis of the Nash equilibrium solutions of the game showed that the pricing strategies of online and offline channels heavily depend not only on the strength of network externality but on the relative efficiency of online channel. When the relative efficiency of online channel is high, the online channel can greatly benefit by the network externality. On the other hand, if the relative efficiency of online channel is low, the online channel may not benefit at all by the network externality.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.3
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• pp.21-28
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• 2020

Aftermarket refers to a market in which a company sells complementary goods, replacements of parts, and upgrade or maintenance services to consumers after selling them main durable goods. Intuitively, consumers who purchase main durable goods become major potential customers in subsequent aftermarket. Thus the existence of the aftermarket has a significant impact on pricing of the main durable goods as well as the aftermarket products. In this study, we analyze the effect of aftermarket on the pricing strategy for a company selling both main durable goods and aftermarket products. To do this we first divided the market into markets where the aftermarket products are indispensable and optional. Based on the proposed market types, the profit maximizing solutions are derived using two-period model, and the impacts of consumers' undervaluation of aftermarket product prices on pricing strategy are analyzed. The results can be summarized as follows : (1) Regardless of the market type, the total profits were found to be inversely proportional to the consumer's awareness accuracy of product prices in the aftermarket. This is in line with marketing efforts that sales companies have made intuitively to make consumers underestimate the cost of the aftermarket. (2) If aftermarket product is indispensable, only revenue from the aftermarket is sought. On the other hand, if aftermarket product is optional, revenue from the main durable good as well as the aftermarket product will be sought simultaneously. (3) Moreover, when aftermarket product is optional, the lower the awareness accuracy of consumers, the higher the price and profit of the main durable goods, while the lower the price and profit of the aftermarket products. This is contrary to the intuition that the lower the consumer's valuation of the costs of aftermarket, the more advantageous it would be to rely on aftermarket products rather than on main durable goods.

• Industrial Engineering and Management Systems
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• v.11 no.2
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• pp.155-164
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• 2012

As the global market becomes more competitive, manufacturing industries face relentless pressure caused by a growing tendency of greater varieties of products, shorter manufacturing cycles and more sophisticated customer requirements. Efficient and effective supplier selection and order allocation decisions are, therefore, important decisions for a manufacturer to ensure stable material flows in a highly competitive supply chain, in particular, when customers are willing to accept products with less desirable product attributes (e.g., color, delivery date) for economic reasons. This paper attempts to solve optimally the challenging problem of supplier selection and order allocation, taking into consideration the customer flexibility for a manufacturer producing multi-products to satisfy the customers' demands in a multi period planning horizon. A new mixed integer programming model is developed to describe the behavior of the supply chain. The objective is to maximize the manufacturer's total profit subject to various operating constraints of the supply chain. Due to the complexity and non-deterministic polynomial-time (NP)-hard nature of the problem, an improved genetic approach is proposed to solve the problem optimally. This approach differs from a canonical genetic algorithm in three aspects: a new selection method to reduce the chance of premature convergence and two problem-specific repair heuristics to guarantee feasibility of the solutions. The results of applying the proposed approach to solve a set of randomly generated test problems clearly demonstrate its excellent performance. When compared with applying the canonical genetic algorithm to locate optimal solutions, the average improvement in the solution quality amounts to as high as ten percent.

• Journal of Energy Engineering
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• v.23 no.4
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• pp.41-48
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• 2014

Leak of liquid has been categorized conventionally into instantaneous release and continuous release. In this study, the spread of cryogenic liquid due to limited period of release is investigated for the first time to establish a new classification method with recognizing the irrationality of the conventional one. Such physical phenomena are governed by simultaneous equations concerning volume, radius and height of pool of the cryogenic liquid, and major parameters are evaporation rate per unit area, time of release, and spill quantity. The simultaneous governing equations is decoupled to get efficiently perturbation solutions. As the results, for the same spill quantity, in view of release model, combined release model that consists of continuous and consecutive instantaneous model is necessary with small time of release, while continuous model is solely required with large time of release. Also, the combined model is necessary for small spill quantity with the same time of release. These two regimes of release are clearly distinguished using the perturbation solution to provide a clear basis for the new classification of release models.

• Archives of Plastic Surgery
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• v.46 no.6
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• pp.544-549
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• 2019

Background As the indications for postmastectomy radiotherapy expand, innovative solutions are required to reduce operative complications and reconstructive failure after prosthetic breast reconstruction. In this study, we investigated the effectiveness of acellular dermal matrix (ADM) inlay grafts in preventing postoperative wound dehiscence of irradiated breasts in the context of prosthetic breast reconstruction. Methods A retrospective analysis was conducted of 45 patients who received two-stage prosthetic reconstruction and radiotherapy following mastectomy. An ADM graft was placed beneath the incisional site during the second-stage operation in 19 patients using marionette sutures, whereas the control group did not receive the ADM reinforcement. Patient demographics and complications such as wound dehiscence, capsular contracture, peri-prosthetic infection, cellulitis, and seroma were compared between the two groups. Results During an average follow-up period of 37.1 months, wound dehiscence occurred significantly less often in the ADM-reinforced closure group (0%) than in the non-ADM group (23.1%) (P=0.032). There was no significant difference between the two groups in relation to other complications, such as capsular contracture, postoperative infection, or seroma. Conclusions The ADM inlay graft is a simple and easily reproducible technique for preventing incisional dehiscence in the setting of radiotherapy after prosthetic breast reconstruction. The ADM graft serves as a buttress to offload tension during healing and provides a mechanical barrier against pathogens. Application of this technique may serve to reduce complications in prosthetic breast reconstruction after radiotherapy.

• Korean Medical Education Review
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• v.18 no.1
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• pp.1-15
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• 2016

In preparing for the unification of North and South Korea, rather than unilaterally over-writing the North's human resource training system with the South's health care human resource development system, it is important to understand the North's system and its ecology and to achieve a balance by seeking out aspects of each of the systems that could be consolidated with each other. The training period in both the North and South's health care human resource development systems is specified to be 6 years, but there is no system for internships or residencies in the North. South Korea introduced a 6-year system for pharmacist education in 2009, but North Korea has been using such a system since the 1970s (currently 5.5 years). In North Korea, training of health care personnel is conducted at various levels: at universities, at vocational schools, and at institutes for training health officials. Various types of training (daytime training, online, and ad hoc programs) are carried out. Also of interest is the North's licensure examination system. Rather than a state examination system as in South Korea, the North favors a graduation exam given by a national graduation examination committee composed of university professors, which awards both graduation certificates and 'permits,' that is, licenses for doctors and pharmacists. In working out a plan for the integration of the two Koreas' systems based on the study and analysis of the North's educational and testing system for doctors and pharmacists, this paper does not place exclusive focus on the distinctions between the systems or cling to negative views. Rather than claim that unification/integration is a practical impossibility, the paper focuses on the similarities between the two systems and maximizes them to uncover an approach for arriving at solutions. It is hoped that the practical data offered in this paper can contribute to the design of a forward-minded unification/integration model.

• Journal of Navigation and Port Research
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• v.40 no.5
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• pp.337-343
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• 2016

The core decisions of bulk shipping businesses can be summarized as the timing and the choice of period for which carrying capacity is traded. In particular, frequent decisions to trade freight either with repeated spot transactions or with a one-off long-term deal critically impact business performance. Even though a variety of freight trading strategies can be employed to facilitate the decisions, chartering practitioners have not been active in utilizing these strategies, and academic research has rarely proposed applicable solutions. The specific properties of freight as a tradable commodity are not properly reflected in existing studies, and limitations have been reported in their application to the real world. This research focused on the establishment of applicable freight trading strategies by taking into account two properties of freight: time perishability and term-dependant pricing. In addition to traditional trading strategies, artificial neural networks were applied for the first time to the test of freight trading strategies. The performances of the trading strategies were measured and compared to produce a remarkable outperformance of the ANN. This research is expected to make a significant contribution to chartering practices by enhancing the quality of chartering decisions and eventually enabling the effective management of freight rate risk. In addition to methodological expansion, the result will propose a way to approach the controversial issue of freight market efficiency.