• Title/Summary/Keyword: Turn-off time

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A novel TIGBT tructure with improved electrical characteristics (향상된 전기적 특성을 갖는 트렌치 게이트형 절연 게이트 바이폴라 트랜지스터에 관한 연구)

  • Koo, Yong-Seo;Son, Jung-Man
    • Journal of IKEEE
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    • v.11 no.4
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    • pp.158-164
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    • 2007
  • In this study, three types of a novel Trench IGBTs(Insulated Gate Bipolar Transistor) are proposed. The first structure has P-collector which is isolated by $SiO_2$ layer to enhance anode-injection-efficiency and enable the device to have a low on-state voltage drop(Von). And the second structure has convex P-base region between both gates. This structure may be effective to distributes electric-field crowded to gate edge. So this structure can have higher breakdown voltage(BV) than conventional trench-type IGBT(TIGBT). The process and device simulation results show improved on-state, breakdown and switching characteristics in each structure. The first one was presented lower on state voltage drop(2.1V) than that of conventional one(2.4V). Also, second structurehas higher breakdown voltage(1220V) and faster turn off time(9ns) than that of conventional structure. Finally, the last one of the proposed structure has combined the two structure (the first one and second one). This structure has superior electric characteristics than conventional structure about forward voltage drop and blocking capability, turnoff characteristics.

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A Novel Approach for Controlling Process Uniformity with a Large Area VHF Source for Solar Applications

  • Tanaka, T.
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.08a
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    • pp.146-147
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    • 2011
  • Processing a large area substrate for liquid crystal display (LCD) or solar panel applications in a capacitively coupled plasma (CCP) reactor is becoming increasingly challenging because of the size of the substrate size is no longer negligible compared to the wavelength of the applied radio frequency (RF) power. The situation is even worse when the driving frequency is increased to the Very High Frequency (VHF) range. When the substrate size is still smaller than 1/8 of the wavelength, one can obtain reasonably uniform process results by utilizing with methods such as tailoring the precursor gas distribution by adjustingthrough shower head hole distribution or hole size modification, locally adjusting the distance between the substrate and the electrode, and shaping shower head holes to modulate the hollow cathode effect modifying theand plasma density distribution by shaping shower head holes to adjust the follow cathode effect. At higher frequencies, such as 40 MHz for Gen 8.5 (2.2 m${\times}$2.6 m substrate), these methods are not effective, because the substrate is large enough that first node of the standing wave appears within the substrate. In such a case, the plasma discharge cannot be sustained at the node and results in an extremely non-uniform process. At Applied Materials, we have studied several methods of modifying the standing wave pattern to adjusting improve process non-uniformity for a Gen 8.5 size CCP reactor operating in the VHF range. First, we used magnetic materials (ferrite) to modify wave propagation. We placed ferrite blocks along two opposing edges of the powered electrode. This changes the boundary condition for electro-magnetic waves, and as a result, the standing wave pattern is significantly stretched towards the ferrite lined edges. In conjunction with a phase modulation technique, we have seen improvement in process uniformity. Another method involves feeding 40 MHz from four feed points near the four corners of the electrode. The phase between each feed points are dynamically adjusted to modify the resulting interference pattern, which in turn modulate the plasma distribution in time and affect the process uniformity. We achieved process uniformity of <20% with this method. A third method involves using two frequencies. In this case 40 MHz is used in a supplementary manner to improve the performance of 13 MHz process. Even at 13 MHz, the RF electric field falls off around the corners and edges on a Gen 8.5 substrate. Although, the conventional methods mentioned above improve the uniformity, they have limitations, and they cannot compensate especially as the applied power is increased, which causes the wavelength becomes shorter. 40 MHz is used to overcome such limitations. 13 MHz is applied at the center, and 40 MHz at the four corners. By modulating the interference between the signals from the four feed points, we found that 40 MHz power is preferentially channeled towards the edges and corners. We will discuss an innovative method of controlling 40 MHz to achieve this effect.

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Greenhouse Gas Reduction from Paddy by Environmentally-Friendly Intermittent Irrigation: A Review (환경 친화적인 간단관개를 통한 논에서의 온실가스 저감)

  • Choi, Joongdae;Uphoff, Norman;Kim, Jonggun;Lee, Suin
    • Journal of Wetlands Research
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    • v.21 no.1
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    • pp.43-56
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    • 2019
  • Irrigated and flooded rice paddy contributes to the greenhouse gas emissions (GHG) that affect climate. This in turn affects the supply and reliability of the water needed for rice production. This dynamic makes current rice production methods foreseeably less sustainable over time while having other undesirable effects. Intermittent irrigation by a means of the system of rice intensification (SRI) and alternate wetting and drying (AWD) methods was reviewed to reduce global warming potential (GWP) from 29% to 90% depending on site-specific characteristics from flooded rice paddy and analyzed to be a promising option for enhancing the productivity of water as well, an increasingly constraining resource. Additional benefits associated with the SRI/AWD can be less arsenic in the grain and less degradation of water quality in the run-off from rice paddies. Adoption and expansion of intermittent irrigation of SRI/AWD may require costly public and private investments in irrigation infrastructure that can precisely make irrigation control, and the involvement and upgrading of water management agencies and farmer organizations to enhance management capabilities. Private and public collaboration as a means of earning carbon credit under the clean-development mechanism (CDM) with SRI/AWD for industries to meet as a part of their GHG emission quota as well as a social contribution and publicity program could contribute to adopt intermittent irrigation and rural investment and development. Also, inclusion of SRI and AWD in programs designed under CDM and/or in official development assistance (ODA) projects could contribute to climate-change mitigation and help to achieve UN sustainable development goals (SDGs).

Access Restriction by Packet Capturing during the Internet based Class (인터넷을 이용한 수업에서 패킷캡쳐를 통한 사이트 접속 제한)

  • Yi, Jungcheol;Lee, Yong-Jin
    • 대한공업교육학회지
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    • v.32 no.1
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    • pp.134-152
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    • 2007
  • This study deals with the development of computer program which can restrict students to access to the unallowable web sites during the Internet based class. Our suggested program can find the student's access list to the unallowable sites, display it on the teacher's computer screen. Through the limitation of the student's access, teacher can enhance the efficiency of class and fulfill his educational purpose for the class. The use of our results leads to the effective and safe utilization of the Internet as the teaching tools in the class. Meanwhile, the typical method is to turn off the LAN (Local Area Network) power in order to limit the student's access to the unallowable web sites. Our program has been developed on the Linux operating systems in the small network environment. The program includes following five functions: the translation function to change the domain name into the IP(Internet Protocol) address, the search function to find the active students' computers, the packet snoop to capture the ongoing packets and investigate their contents, the comparison function to compare the captured packet contents with the predefined access restriction IP address list, and the restriction function to limit the network access when the destination IP address is equal to the IP address in the access restriction list. Our program can capture all passing packets through the computer laboratory in real time and exactly. In addition, it provides teacher's computer screen with the all relation information of students' access to the unallowable sites. Thus, teacher can limit the student's unallowable access immediately. The proposed program can be applied to the small network of the elementary, junior and senior high school. Our research results make a contribution toward the effective class management and the efficient computer laboratory management. The related researches provides teacher with the packet observation and the access limitation for only one host, but our suggested program provides teacher with those for all active hosts.

How Can Non.Chaebol Companies Thrive in the Chaebol Economy? (비재벌공사여하재재벌경제중생존((非财阀公司如何在财阀经济中生存)? ‐공사층면영소전략적분석(公司层面营销战略的分析)‐)

  • Kim, Nam-Kuk;Sengupta, Sanjit;Kim, Dong-Jae
    • Journal of Global Scholars of Marketing Science
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    • v.19 no.3
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    • pp.28-36
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    • 2009
  • While existing literature has focused extensively on the strengths and weaknesses of the Chaebol and their ownership and governance, there have been few studies of Korean non-Chaebol firms. However, Lee, Lee and Pennings (2001) did not specifically investigate the competitive strategies that non-Chaebol firms use to survive against the Chaebol in the domestic Korean market. The motivation of this paper is to document, through four exploratory case studies, the successful competitive strategies of non-Chaebol Korean companies against the Chaebol and then offer some propositions that may be useful to other entrepreneurial firms as well as public policy makers. Competition and cooperation as conceptualized by product similarity and cooperative inter.firm relationship respectively, are major dimensions of firm.level marketing strategy. From these two dimensions, we develop the following $2{\times}2$ matrix, with 4 types of competitive strategies for non-Chaebol companies against the Chaebol (Fig. 1.). The non-Chaebol firm in Cell 1 has a "me-too" product for the low-end market while conceding the high-end market to a Chaebol. In Cell 2, the non-Chaebol firm partners with a Chaebol company, either as a supplier or complementor. In Cell 3, the non-Chaebol firm engages in direct competition with a Chaebol. In Cell 4, the non-Chaebol firm targets an unserved part of the market with an innovative product or service. The four selected cases such as E.Rae Electronics Industry Company (Co-exister), Intops (Supplier), Pantech (Competitor) and Humax (Niche Player) are analyzed to provide each strategy with richer insights. Following propositions are generated based upon our conceptual framework: Proposition 1: Non-Chaebol firms that have a cooperative relationship with a Chaebol will perform better than firms that do not. Proposition 1a; Co-existers will perform better than Competitors. Proposition 1b: Partners (suppliers or complementors) will perform better than Niche players. Proposition 2: Firms that have no product similarity with a Chaebol will perform better than firms that have product similarity. Proposition 2a: Partners (suppliers or complementors) will perform better than Co.existers. Proposition 2b: Niche players will perform better than Competitors. Proposition 3: Niche players should perform better than Co-existers. Proposition 4: Performance can be rank.ordered in descending order as Partners, Niche Players, Co.existers, Competitors. A team of experts was constituted to categorize each of these 216 non-Chaebol companies into one of the 4 cells in our typology. Simple Analysis of Variance (ANOVA) in SPSS statistical software was used to test our propositions. Overall findings are that it is better to have a cooperative relationship with a Chaebol and to offer products or services differentiated from a Chaebol. It is clear that the only profitable strategy, on average, to compete against the Chaebol is to be a partner (supplier or complementor). Competing head on with a Chaebol company is a costly strategy not likely to pay off for a non-Chaebol firm. Strategies to avoid head on competition with the Chaebol by serving niche markets with differentiated products or by serving the low-end of the market ignored by the Chaebol are better survival strategies. This paper illustrates that there are ways in which small and medium Korean non-Chaebol firms can thrive in a Chaebol environment, though not without risks. Using different combinations of competition and cooperation firms may choose particular positions along the product similarity and cooperative relationship dimensions to develop their competitive strategies-co-exister, competitor, partner, niche player. Based on our exploratory case-study analysis, partner seems to be the best strategy for non-Chaebol firms while competitor appears to be the most risky one. Niche players and co-existers have intermediate performance, though the former do better than the latter. It is often the case with managers of small and medium size companies that they tend to view market leaders, typically the Chaebol, with rather simplistic assumptions of either competition or collaboration. Consequently, many non-Chaebol firms turn out to be either passive collaborators or overwhelmed competitors of the Chaebol. In fact, competition and collaboration are not mutually exclusive, and can be pursued at the same time. As suggested in this paper, non-Chaebol firms can actively choose to compete and collaborate, depending on their environment, internal resources and capabilities.

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The Conceptual Intersection between the Old and the New and the Transformation of the Traditional Knowledge System (신구(新舊) 관념의 교차와 전통 지식 체계의 변용)

  • Lee, Haenghoon
    • The Journal of Korean Philosophical History
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    • no.32
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    • pp.215-249
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    • 2011
  • This essay reflects on the modernity of Korea by examining the transformation of the traditional knowledge system from a historico-semantic perspective with its focus on the opposition and collision of the old and the new conception occurred in the early period(1890~1910) of the acceptance of the Western modern civilization. With scientific success, trick of reason, Christianity and evolutionary view of history, the Western modernity regarded itself as a peak of civilization and forced the non-Western societies into the world system in which they came to be considered as 'barbarism(野蠻)' or 'half-enlightened(半開).' The East Asian civilization, which had its own history for several centuries, became degraded as kind of delusion and old-fashioned customs from which it ought to free itself. The Western civilization presented itself as exemplary future which East Asian people should achieve, while East Asian past traditions came to be conceived as just unnecessary vestiges which it was better to wipe out. It can be said that East Asian modernization was established through the propagation and acceptance of the modern products of the Western civilization rather than through the preservation of its past experience and pursuit of the new at the same time. Accordingly, it is difficult to apply directly to East Asian societies Koselleck's hypothesis; while mapping out his Basic Concept of History, he assumed that, in the so-called 'age of saddle,' semantic struggle over concepts becomes active between the past experience and the horizon of expectation on the future, and concepts undergoes 'temporalization', 'democratization', 'ideologization', 'politicization.'The struggle over the old and new conceptions in Korea was most noticeable in the opposition of the Neo-Confucian scholars of Hwangseongsinmun and the theorists of civilization of Doknipsinmun. The opposition and struggle demanded the change of understanding in every field, but there was difference of opinion over the conception of the past traditional knowledge system. For the theorists of civilization, 'the old(舊)' was not just 'past' and 'old-fashioned' things, but rather an obstacle to the building of new civilization. On the other hand, it contained the possibility of regeneration(新) for the Neo-Confucian scholars; that is, they suggested finding a guide into tomorrow by taking lessons from the past. The traditional knowledge system lost their holy status of learning(聖學) in the process of its change into a 'new learning(新學),' and religion and religious tradition also weakened. The traditional knowledge system could change itself into modern learning by accepting scientific methodology which pursues objectivity and rationality. This transformation of the traditional knowledge system and 'the formation of the new learning from the old learning' was accompanied by the intersection between the old and new conceptions. It is necessary to pay attention to the role played by the concept of Sil(hak)(實學) or Practical Learning in the intersection of the old and new conceptions. Various modern media published before and after the 20th century show clearly the multi-layered development of the old and new conceptions, and it is noticeable that 'Sil(hak)' as conceptual frame of reference contributed to the transformation of the traditional knowledge system into the new learning. Although Silhak often designated, or was even considered equivalent to, the Western learning, Neo-Confucian scholars reinterpreted the concept of 'Silhak' which the theorists of civilization had monopolized until then, and opened the way to change the traditional knowledge system into the new learning. They re-appropriated the concept of Silhak, and enabled it to be invested with values, which were losing their own status due to the overwhelming scientific technology. With Japanese occupation of Korea by force, the attempt to transform the traditional knowledge system independently was obliged to reach its own limit, but its theory of 'making new learning from old one' can be considered to get over both the contradiction of Dondoseogi(東道西器: principle of preserving Eastern philosophy while accepting Western technology) and the de-subjectivity of the theory of civilization. While developing its own logic, the theory of Dongdoseogi was compelled to bring in the contradiction of considering the indivisible(道and 器) as divisible, though it tried to cope with the reality where the principle of morality and that of competition were opposed each other and the ideologies of 'evolution' and 'progress' prevailed. On the other hand, the theory of civilization was not free from the criticism that it brought about a crack in subjectivity due to its internalization of the West, cutting itself off from the traditional knowledge system.

A Study on Perceived Quality affecting the Service Personal Value in the On-off line Channel - Focusing on the moderate effect of the need for cognition - (온.오프라인 채널에서 지각된 품질이 서비스의 개인가치에 미치는 영향에 관한 연구 -인지욕구의 조정효과를 중심으로-)

  • Sung, Hyung-Suk
    • Journal of Distribution Research
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    • v.15 no.3
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    • pp.111-137
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    • 2010
  • The basic purpose of this study is to investigate perceived quality and service personal value affecting the result of long-term relationship between service buyers and suppliers. This research presented a constructive model(perceived quality affecting the service personal value and the moderate effect of NFC) in the on off line and then propose the research model base on prior researches and studies about relationships among components of service. Data were gathered from respondents who visit at the education service market. For this study, Data were analyzed by AMOS 7.0. We integrate the literature on services marketing with researches on personal values and perceived quality. The SERPVAL scale presented here allows for the creation of a common ground for assessing service personal values, giving a clear understanding of the key value dimensions behind service choice and usage. It will lead to a focus of future research in services marketing, extending knowledge in the field and stimulating further empirical research on service personal values. At the managerial level, as a tool the SERPVAL scale should allow practitioners to evaluate and improve the value of a service, and consequently, to define strategies and actions to address services for customers based on their fundamental personal values. Through qualitative and empirical research, we find that the service quality construct conforms to the structure of a second-order factor model that ties service quality perceptions to distinct and actionable dimensions: outcome, interaction, and environmental quality. In turn, each has two subdimensions that define the basis of service quality perceptions. The authors further suggest that for each of these subdimensions to contribute to improved service quality perceptions, the quality received by consumers must be perceived to be reliable, responsive, and empathetic. Although the service personal value may be found in researches that explore individual values and their consequences for consumer behavior, there is no established operationalization of a SERPVAL scale. The inexistence of an established scale, duly adapted in order to understand and analyze personal values behind services usage, exposes the need of a measurement scale with such a purpose. This need has to be rooted, however, in a conceptualization of the construct being scaled. Service personal values can be defined as a customer's overall assessment of the use of a service based on the perception of what is achieved in terms of his own personal values. As consumer behaviors serve to show an individual's values, the use of a service can also be a way to fulfill and demonstrate consumers'personal values. In this sense, a service can provide more to the customer than its concrete and abstract attributes at both the attribute and the quality levels, and more than its functional consequences at the value level. Both values and services literatures agree, that personal value is the highest-level concept, followed by instrumental values, attitudes and finally by product attributes. Purchasing behaviors are agreed to be the end result of these concepts' interaction, with personal values taking a major role in the final decision process. From both consumers' and practitioners' perspectives, values are extremely relevant, as they are desirable goals that serve as guiding principles in people's lives. While building on previous research, we propose to assess service personal values through three broad groups of individual dimensions; at the self-oriented level, we use (1) service value to peaceful life (SVPL) and, at the social-oriented level, we use (2) service value to social recognition (SVSR), and (3) service value to social integration (SVSI). Service value to peaceful life is our first dimension. This dimension emerged as a combination of values coming from the RVS scale, a scale built specifically to assess general individual values. If a service promotes a pleasurable life, brings or improves tranquility, safety and harmony, then its user recognizes the value of this service. Generally, this service can improve the user's pleasure of life, since it protects or defends the consumer from threats to life or pressures on it. While building upon both the LOV scale, a scale built specifically to assess consumer values, and the RVS scale for individual values, we develop the other two dimensions: SVSR and SVSI. The roles of social recognition and social integration to improve service personal value have been seriously neglected. Social recognition derives its outcome utility from its predictive utility. When applying this underlying belief to our second dimension, SVSR, we assume that people use a service while taking into consideration the content of what is delivered. Individuals consider whether the service aids in gaining respect from others, social recognition and status, as well as whether it allows achieving a more fulfilled and stimulating life, which might then be revealed to others. People also tend to engage in behavior that receives social recognition and to avoid behavior that leads to social disapproval, and this contributes to an individual's social integration. This leads us to the third dimension, SVSI, which is based on the fact that if the consumer perceives that a service strengthens friendships, provides the possibility of becoming more integrated in the group, or promotes better relationships at the social, professional or family levels, then the service will contribute to social integration, and naturally the individual will recognize personal value in the service. Most of the research in business values deals with individual values. However, to our knowledge, no study has dealt with assessing overall personal values as well as their dimensions in a service context. Our final results show that the scales adapted from the Schwartz list were excluded. A possible explanation is that although Schwartz builds on Rokeach work in order to explore individual values, its dimensions might be especially focused on analyzing societal values. As we are looking for individual dimensions, this might explain why the values inspired by the Schwartz list were excluded from the model. The hierarchical structure of the final scale presented in this paper also presents theoretical implications. Although we cannot claim to definitively capture the dimensions of service personal values, we believe that we come close to capturing these overall evaluations because the second-order factor extracts the underlying commonality among dimensions. In addition to obtaining respondents' evaluations of the dimensions, the second-order factor model captures the common variance among these dimensions, reflecting the respondents' overall assessment of service personal values. Towards this fact, we expect that the service personal values conceptualization and measurement scale presented here contributes to both business values literature and the service marketing field, allowing for the delineation of strategies for adding value to services. This new scale also presents managerial implications. The SERPVAL dimensions give some guidance on how to better pursue a highly service-oriented business strategy. Indeed, the SERPVAL scale can be used for benchmarking purposes, as this scale can be used to identify whether or not a firms' marketing strategies are consistent with consumers' expectations. Managerial assessment of the personal values of a service might be extremely important because it allows managers to better understand what customers want or value. Thus, this scale allows us to identify what services are really valuable to the final consumer; providing knowledge for making choices regarding which services to include. Traditional approaches have focused their attention on service attributes (as quality) and service consequences(as service value), but personal values may be an important set of variables to be considered in understanding what attracts consumers to a certain service. By using the SERPVAL scale to assess the personal values associated with a services usage, managers may better understand the reasons behind services' usage, so that they may handle them more efficiently. While testing nomological validity, our empirical findings demonstrate that the three SERPVAL dimensions are positively and significantly associated with satisfaction. Additionally, while service value to social integration is related only with loyalty, service value to peaceful life is associated with both loyalty and repurchase intent. It is also interesting and surprising that service value to social recognition appears not to be significantly linked with loyalty and repurchase intent. A possible explanation is that no mobile service provider has yet emerged in the market as a luxury provider. All of the Portuguese providers are still trying to capture market share by means of low-end pricing. This research has implications for consumers as well. As more companies seek to build relationships with their customers, consumers are easily able to examine whether these relationships provide real value or not to their own lives. The selection of a strategy for a particular service depends on its customers' personal values. Being highly customer-oriented means having a strong commitment to customers, trying to create customer value and understanding customer needs. Enhancing service distinctiveness in order to provide a peaceful life, increase social recognition and gain a better social integration are all possible strategies that companies may pursue, but the one to pursue depends on the outstanding personal values held by the service customers. Data were gathered from 284 respondents in the korean discount store and online shopping mall market. This research proposed 3 hypotheses on 6 latent variables and tested through structural equation modeling. 6 alternative measurements were compared through statistical significance test of the 6 paths of research model and the overall fitting level of structural equation model. and the result was successful. and Perceived quality more positively influences service personal value when NFC is high than when no NFC is low in the off-line market. The results of the study indicate that service quality is properly modeled as an antecedent of service personal value. We consider the research and managerial implications of the study and its limitations. In sum, by knowing the dimensions a consumer takes into account when choosing a service, a better understanding of purchasing behaviors may be realized, guiding managers toward customers expectations. By defining strategies and actions that address potential problems with the service personal values, managers might ultimately influence their firm's performance. we expect to contribute to both business values and service marketing literatures through the development of the service personal value. At a time when marketing researchers are challenged to provide research with practical implications, it is also believed that this framework may be used by managers to pursue service-oriented business strategies while taking into consideration what customers value.

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