• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.27 no.2
• /
• pp.221-233
• /
• 2017

The array equations are commonly used for analysis and conceptual design of active sonar projector arrays. Calculation of the radiation impedance matrix poses a major computational bottleneck for the solution of the array equations, which leads to a dramatic increase in computational load as the number of constituent transducers increases. Here, we propose an iteration-based solution method that does not require the calculation of the radiation impedance matrix, as a computationally efficient alternative to the status quo. The validity of the iteration-based analysis is judged against the full finite-element analysis that includes the entire array as well as the medium. The array equations for the 1/3-sector of a cylindrical array comprised of 48 Tonpilz transducers are augmented by the lumped element models, and are solved iteratively for the acoustic and electro-mechanical characteristics. The iteration-based analysis exhibits rapid convergence and accuracy comparable with the FE analysis. Simulations also reveal that the acoustic coupling between transducers has more pronounced effects on the electro-mechanical characteristics of individual transducers than the acoustic performance of the array.

• Journal of Korean Society of Transportation
• /
• v.22 no.4 s.75
• /
• pp.19-30
• /
• 2004

Due to the inefficient operation of the existing logistic facilities, the complicated distribution structure, and closed utilization of logistic information are causing high logistic costs. The general improvement in the distribution structure and the expansion of the logistic facilities are needed for solving these problems. However, existing unit-scale forecast is not considering the loading and unloading characteristics of the trucks and the improvement of operation efficiency from the mechanization and automation of the loading and unloading works. The queuing theory based on the status quo of the cargo trucks to the cargo terminals is considered in this study. The optimal scale estimation method(OSCM) which the loading and unloading characteristics of the cargo trucks were taken into consideration was suggested. Also, the relationship between the optimal scale of the cargo terminal and the mechanization, automation, and informationization of the present loading and unloading system was investigated. As a result, it showed that the regularity of the truck arrival and service times had less influence on the scale of the cargo terminal, but the improvement of the loading and unloading speeds and the service rate of the trucks did more influence on it.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.23 no.2
• /
• pp.17-31
• /
• 2020

In the field of environmental landscape architecture, the internet medium is used as an effective communication tool not only in the private level but also in the policy level. Recently, the active utilization of mobile web service is emphasized as the time changes, but there is not much improvement or advance in services due to lack of relevant studies. Therefore, this study is intended to provide basic data needed for improvement and advance by researching the quality of mobile web service among multichannel services provided in environmental landscape architecture related internet media. The model for measuring service quality is SERVQUAL, which was verified in the study of Choi(2015), Choi and Koo(2016), and the final valid samples are total 230. First, the subjects were analyzed as the representative media that are possible to acquire comprehensive knowledge related to environmental landscape architecture. Second, the highest importance level in each subsection was 'protection and security maintenance of customer information' followed by 'Reliability about accurate information supply'. Regarding performance level, 'Reliability about accurate information supply' and 'professional knowledge to communicate with users' are highly evaluated. Third, regarding Importance-Performance Analysis(IPA), the first priority management should is 'Tangibles', and the next are 'Responsibility' and 'Empathy'. The ones for maintenance of the status quo are 'Reliability' and 'Assurance', and there is none for effort reduction. Meanwhile, regarding the importance of each factor and difference in the quality of PC web service and mobile web service studied before, the biggest difference is in 'Tangibles', followed by 'Assurance', 'Empathy', 'Responsibility' and 'Reliability'. It is suggested that the revitalization of Landscape information science(LB1106) presented in the National Science&Technology Standard Classification System is needed. In the future, it is necessary to research the change trend on users' response through continuous evaluation of improved mobile web service.

• Journal of the Korean Society for information Management
• /
• v.18 no.1
• /
• pp.23-42
• /
• 2001

The purpose of this study was to obtain descriptive information about public library connectivity and use related to the Internet in Korea. Questionnaire was sent to all of the 364 public libraries in the nation. The data show that, as of the end of 1999,70.9% of the 351 public libraries which answered the questionnaire had some type of connection to the Internet, and 50.4% of them provided public Internet access services. The infrastructure of hardware and telecommunication, use policy for their public access Internet services were analysed. Public librarians were asked to evaluate their public Internet services. Overall the study found that the level of the nation' s public library Internet services were not satisfactory in quality and quantity. It also found that there were some significant disparities among public libraries in metropolitan areas, medium and small sized cities, and rural counties.

• Environmental and Resource Economics Review
• /
• v.17 no.4
• /
• pp.875-901
• /
• 2008

This article estimates the economic values of changes in water quality of the Paldang Watershed by using the Choice Experiment (CE). The conditional logit model estimation results show that a small improvement in water quality from the 'status quo' level to the level of 'very good' increases average household's monthly utility by 3,157 Won, whereas a water quality degradation down to the 'normal' level gives rise to an increase in the monthly average utility by 9,649 Won. The corresponding social gain and loss of water quality changes to the Metropolitan Area were thus estimated about 285 billion Won and 872 billion Won, respectively. This article seems meaningful in that it resorts to the new water ecosystem classification criteria and indices that are respondent-friendly. They help a CE study like this to overcome one of its critical weakness that the number and contents of attributes of a CE study can quickly add to the information overload problem, especially where the environmental good under investigation is hard for ordinary respondents to understand.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.12
• /
• pp.7385-7393
• /
• 2013

Background: Only few epidemiological data on primary central nervous system (CNS) tumors in Shanghai have been reported. Methods: All cases of primary CNS tumors that were registered at Center for Disease Control and Prevention (CDC) were collected (1973-2007: urban Shanghai; 2003-2007: whole Shanghai city). Trends were analyzed using joinpoint analysis and rates were stratified by age, gender and region. Histological data were collected from both CDC and Huashan Hospital. Results: From 1973 to 2007, the five-year average incidence rate in urban Shanghai increased in both genders, especially in the elderly population. Joinpoint analysis showed the age-adjusted incidence rate for males increased first but then plateaued, whilst rates for females continued increasing over the 35 years. For the five-year status quo (2003-2007), rural had a higher age-adjusted incidence rate than urban populations, and females higher than males, especially those with advanced age. According to CDC (2003-2007) and Huashan Hospital (1951-2011), the two most common histological subtypes were neuroepithelial tumors (with male predominance) and meningiomas (with female predominance). Conclusions: In Shanghai, a steadily increased incidence rate of primary CNS tumors was observed in general, and in the elderly and female population in particular.

• The Journal of the Korea Contents Association
• /
• v.18 no.7
• /
• pp.577-589
• /
• 2018

The future of ROK-US alliance has not been discussed in detail by both governments since early 2000s. However, it is becoming more apparent that ROK-US alliance is facing various daunting challenges. The new administrations both in ROK and US might have different perspectives about the future of alliance. In the process of resolving outstanding North Korean nuclear issue, the alliance can face challenges to change its fundamental features such as halting joint military exercise. ROK-US governments also agreed to transfer wartime operational control as soon as possible. All those factors indicates the growing necessity to articulate the future of ROK-US alliance. ROK and US needs to facilitate to dialogue for future alliance with the possible scenarios of changing security environment such as maintaining status quo, reconciliation of North and South Korea, and entering the reunification stage. In each phase, ROK-US has to develop the goal for the alliance, military institution to implement the alliance, role of USFK, and etc. It is imperative to develop the road map for future ROK-US alliance at this stage to avoid unnecessary folly.

• Korean Journal of Environment and Ecology
• /
• v.23 no.2
• /
• pp.151-160
• /
• 2009

To investigate the vegetation structure of the section from Naesosa to Naebyonsan district, thirty plots which Size is $100m^2$ were set up in the Byeonsan Peninsula National Park. According to the classification(TWINSPAN) and ordination(DCA) analysis which were used for community division, the plots are appeared in uncontiguity with each ones. At the end of classification analysis, the community was divided into the four groups of Pinus densiflora(I), Pinus densiflora-Quercus serrata(II), Zelkova serrata-Rhamnella frangulioides(III) and Aphanaghe aspera-Rhamnella frangulioides community(IV). Through the results, Pinus densiflora community coast-sided will be going with status quo, but Pinus densiflora-Quercus serrata community inland-sided will progress toward Q. serrata dominated community. It was turned out that the forest of the Byeonsan Peninsula National Park is about over 40-year-old through tree ring analysis.

• Lingua Humanitatis
• /
• v.8
• /
• pp.175-198
• /
• 2006

Quite a few historiographers of language science have measured the applicability of the term 'revolution' toward the line of work initiated by Chomsky, with the conclusion to the positive or negative effect as the case may be. This paper starts out with a brief review of this issue, with an interim conclusion that, while Chomskyan linguistics may be regarded as revolutionary in certain aspects, terms like 'revolution' and 'paradigm' are hardly applicable here in the way they were originally intended by Thomas Kuhn. It can be said, nontechnically, that the model of theory under discussion is at once 'revolutionary' and 'evolutionary' - in the sense that revolutions in linguistics have not resulted in abrupt loss of continuity with past 'paradigms', if there were any such. Chomsky's theory of language plays the same role of consolidation and refinement of structuralism that, say, the neogrmmarians played in their day. It has continued some fundamental traits of its predecessor, recovered others, and unwittingly rediscovered still others. But this is not the main thrust of the present paper. For, even if Chomskyan theory were to be looked upon as straightforwardly 'revolutionary', that revolution has not been a felicitous one. Some critic (Pieter A. M. Seuren, to be specific) goes as far as to say that "largely as a result of Chomsky's actions, linguistics is now sociologically in a very unhealthy state $\cdots$ to the point even of threatening to make that whole school of linguistics intellectually irrelevant." Besides, under the present state of language science that strikes one as typical of what Kuhn has characterized as "pre-paradigmatic" insecurity and disharmony, an unhealthy situation might take place if we were to think of the theoretical disagreements as conflicts between 'incommensurable' viewpoints-between 'rival paradigms' as it were-thereby avoiding or evading rational discussion. Another danger concerns the bandwagon effect, with linguists prematurely boarding each novel theory seemingly destined for popularity, for fear of being left clinging to an outdated 'paradigm.' Here lies another reason why the notion of 'revolution', Kuhnian or not, might as well be put aside, in the historiography of linguistics at the least.

• Journal of The Korean Association of Information Education
• /
• v.10 no.1
• /
• pp.143-152
• /
• 2006

The aim of this study was to analyze effects of a blended learning program based on case study approach and to suggest implications in appropriately evaluating blended learning in practices for corporate education and training. In order to achieve the goal, issues such as the ones related to blended learning including development and status quo of blended learning programs in the field of corporate education and training and operation models for the blended learning were reviewed. Then, the outcomes of a blended learning program were completely analyzed through systems approach. The methodology of the study was a mixed research method which was comprised of quantitative and qualitative approaches. The results of quantitative analysis showed that blended learning itself seemed to have significant effects on the leadership capability in general assessment and self assessment. The most viable effects of blended learning in leadership training are said to be actual change of actions and activities in leadership capability of the participants followed by changes in their job tasks contributing to improving the managerial performance of the company, good transfer to current job tasks, and implementation of the practice plans.