• The Transactions of the Korean Institute of Power Electronics
• /
• v.10 no.4
• /
• pp.411-419
• /
• 2005

In this paper, a sliding mode observer for solar array current estimation in the photovoltaic power generation system is presented. The solar array current estimation Information is obtained from the sliding mode observer and fed into the maximum power point tracker to update the reference voltage. The parameter values such as inverter dc link capacitances cm be changed up to 50$\%$ from their nominal values and the linear observer can't estimate the correct state values under the parameter variations and noisy environments. The configuration of sliding mode observer is simple, but it shows the robust tracking performance against parameter variations and modeling uncertainties. In this paper, the method for constructing the sliding mode observer using equivalent control input is presented and the convergence of the proposed observer is verified by the Lyapunov method. The mathematical modeling and the experimental results verify the validity of the proposed method.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.11
• /
• pp.7300-7309
• /
• 2015

The purpose of the this study was to identify the relationship between stress, emotional intelligence and academic achievement of nursing students. Self-report questionnaire was given to 157 nursing students(3rd, 4th grade) in Korea and K university students were completed the survey. The data were collected November 24th to December 12th. SPSS WIN 18.0. program was used to analyze data and descriptive statistics, t-test, ANOVA and Pearson correlation coefficients were used to analyse the relationship. Stress were significantly correlations with emotional intelligence and academic achievement in nursing students. These findings indicate that to decrease stress and to increase academic achievement of nursing students, it is necessary to development and investigate a program for managing stress among nursing students.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.24 no.12B
• /
• pp.2249-2261
• /
• 1999

In this paper, we describe the design and implementation of the Label Distribution Protocol (LDP) for Multiprotocol Label Switching System. We review the implementation issues of LDP that is required to make a gigabit switched router, and propose a detail design of it. We present the data structures and procedures for the LDP as a result, which are based on IETF standard. We present design issues for applying this to carrier class products. The implemented protocol could afford 40,000 entries of the IP routing table that is required for deploying this system to commercialized data network. Furthermore this system implemented using the standard API of Unix, as a result, it has portability. By implementing LDP based on the international standard and these implementation issues, we expect that the implemented LDP will be interoperable with other commercialized products. We prove the validity of the design of the LDP through prototyping, and also verify the prototype with the specification using the process algebra and the performance analysis.

• The KIPS Transactions:PartD
• /
• v.9D no.4
• /
• pp.639-650
• /
• 2002

We have to carry out systematic, definite requirements analysis for the successful development of software. The UML gives the ways to grasp user or customer requirements and decide the boundary of business systems from the use case modeling. This paper presents how to extract use case diagram from the requirements specification systematically by applying the standardized rules as a part of the study for use case modeling. We modify requirements specification by applying $R_{RS}$ (Rules for Requirements Specification) and extract actor, use case, relationship by applying $R_{A}$(Rules for Actors), $R_{U}$(Rules for Use Cases) and $R_{R}$(Rules for Relationships) to the modified requirements specification separately and then become to make out use case diagram in the end. By applying the rules presented in this paper to the requirements specification for personnel management, we can reduce the existing difficulties of extracting use case diagram based on the narrative descriptions without any standardized rules.rules.

• The KIPS Transactions:PartC
• /
• v.9C no.6
• /
• pp.847-856
• /
• 2002

Cellular network applications are growing drastically and this requires a fast and efficient transport method between the base station and the mobile switching center. One possible solution is to use ATM links. The low data rate and small-sized packets in the typical cellular applications imply that significant amount of link bandwidth would be wasted, if this small sized packet is carried by one ATM cell. For efficient operation for such cellular and low bit rate applications, a new type of ATM Adaptation Layer, AAL Type 2, has been proposed. In this paper, the principles of AAL Type 2 are briefly described along with the introduction of other alternatives which have formed the basis for this new AAL. The result from the simulation to study the performance of the AAL Type 2 is discussed from the view point of packet delay and ATM cell use efficiency. Due to the variable size of packets in this application, the fairness issue in serving variable sized packets is also discussed along with the effect of fair queueing algorithm implemented at AAL Type 2.

• Journal of KIISE:Software and Applications
• /
• v.27 no.4
• /
• pp.448-462
• /
• 2000

Coordinate constructions in natural language pose a number of difficulties to natural language processing units, due to the increased complexity of syntactic analysis, the syntactic ambiguity of the involved lexical items, and the apparent deletion of predicates in various places. In this paper, we address the syntactic characteristics of the coordinate constructions in Korean from the viewpoint of constructing a competence grammar, and present a version of combinatory categorial grammar for the analysis of coordinate constructions in Korean. We also show how to utilize a unified lexicon in the proposed grammar formalism in deriving the sentential semantics and associated information structures as well, in order to capture the discourse functions of coordinate constructions in Korean. The presented analysis conforms to the common wisdom that coordinate constructions are utilized in language not simply to reduce multiple sentences to a single sentence, but also to convey the information of contrast. Finally, we provide an analysis of sample corpora for the frequency of coordinate constructions in Korean and discuss some problematic cases.

• Journal of Science Education
• /
• v.43 no.3
• /
• pp.284-299
• /
• 2019

The purpose of this study is to investigate elementary school students' conceptions about the energy represented in the integrated theme 'Energy and life' of the 2015 revised science curriculum. The instruments were developed to grasp students' understanding about 'the concepts of energy,' 'forms of energy,' 'conversion of energy,' and 'energy use of plants and animals.' The surveys were conducted on 92 elementary school students in Seoul. The students' answers were analyzed by descriptive statistics, clouds and semantic network analysis. The results are as follows: 'Electricity' and 'electric energy' were most frequently mentioned as the associated concepts to energy and forms of energy, respectively. Also, the daily use of energy was mixed to the use in science. According to conceptual hierarchy, understanding of energy conversion was dependent on the understanding of energy forms. Although students have basic concepts about the energy use of plants and animals, they had some misconceptions and lack of understanding. The educational implications were discussed to teach 'Energy and Life' as integrated theme in new elementary school curriculum.

• Journal of the Korean association of regional geographers
• /
• v.12 no.3
• /
• pp.392-407
• /
• 2006

This paper was written on the purpose of examining and analyzing Sungho's view of geography in 'Cheonjimun(天地門)', a part of 'Sunghosaseol(星湖僿說)'. Sungho is not a geographer who specialized in geography, His view is neither structural in methodological approach nor profound in geographical thought. Unfortunately, he looks to be possessed by geomantic thought(風水地理思想) in explaining geographical features and native customs. And he focused and emphasized only on defensive function in place location. As a whole, however, he had a good grasp of and analyzed about geographical topics which are related to human life and we must take interest in. Therefore, in his view, there is a love for country and hometown. Especially, it has to be highly appreciated that he tried to explain his view in analytical and practical perspective with an unspoken advice which things necessary for human life have to be used to available knowledge.

• Journal of the Korean association of regional geographers
• /
• v.10 no.3
• /
• pp.554-567
• /
• 2004

Since the 1980s, the academic interests on the regional geography have been renewed. This trend is usually called 'Renaissance' of the regional geography. Given this context, to explore diverse theories and methodologies in the regional geography is of much significance. Particularly, to examine the regional geography in Germany widens the understanding of not only the history, strength, and weakness of the regional geography, but also the discipline's status in the field of geography. This paper discusses the regional geography in Germany before World War II, focusing on varieties of theories and methods as well as the historical trajectory of the German regional geography. This discussion may well be significant in that 'Laenderkunde' became an important paradigm in the discipline of geography in Germany during the pre-World War II period.

• Journal of Sensor Science and Technology
• /
• v.10 no.1
• /
• pp.33-41
• /
• 2001

Wire ropes have been widely used in industrial applications, wherever heavy weight should be carried safely or mechanical energy should be transmitted fast. Especially, wire rope failures in operating elevator may lead to extensive property damage and serious injury to nearby personnel. Hence, it is very important to inspect wire rope periodically. Failure defection of wire rope requires fundamental knowledge of wire rope construction, rope behavior, properties of fault, sensing and signal processing method. In this research, the development of a new fault detecting system incorporating Hall-effect sensors to detect flaws such as abrasion, broken wire, corrosion and deformation for aged wire ropes in elevator, is described. For using a detector as a portable instrument, several performances for implementing sensing part with Hall-effect sensor, analog signal processing unit and programs are described. Experiments and field testing results for the implemented detecting system are also given. As a result, it is verified that the detecting system has good efficiency for inspecting faults of aged wire ropes in service.