• Journal of Korean Society of Coastal and Ocean Engineers
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• v.4 no.2
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• pp.72-82
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• 1992

To accurately estimate nearshore current in shallow water regions. it is necessary to investigate the irregular wave transformation characteristics and radiation stress produced by random sea waves. This research is to investigate the application or the individual wave Analysis Method. the Component Wave Analysis Method and Representative Wave Analysis Method in the shallow water region. These methods were estimated by wave shallowing transformation when the waves propagate from deep water to shallow water region b)r generating regular waves, two component waves and irregular waves (Bretschneider-Mitsuyasu type). That is, the Indivisual Wave Analysis Method is to investigate from the viewpoint of shallow water transformation of wave statistical characteristics and their zero-down-crossing waves (wave height period and wave celerity). And the component Wave Analysis Method is to investigate from the view point of shallow water transformation of basic frequency component wave and their interference frequency component wave. In addition, this research is to compare the measured mean water level elevation with the calculated one from radiation stress of irreguar waves that is assumed in the three methods above.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.85-92
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• 2010

In this paper, we propose a Clustering-based Cooperative Routing using OFDM (CCRO) for supporting transmission efficiency in mobile wireless sensor networks. The main features and contributions of the proposed method are as follows. First, the clustering method which uses the location information of nodes as underlying infrastructure for supporting stable transmission services efficiently is used. Second, cluster-based cooperative data transmission method is used for improving data transmission and reliability services. Third, OFDM based data transmission method is used for improving data transmission ratio with channel efficiency. Fourth, we consider realistic approach in the view points of the mobile ad-hoc wireless sensor networks while conventional methods just consider fixed sensor network environments. The performance evaluation of the proposed method is performed via simulation using OPNET and theoretical analysis. The results of performance evaluation show improvement of transmission efficiency.

• Journal of Digital Convergence
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• v.14 no.5
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• pp.349-358
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• 2016

This study identifies the relationships between professional values, bioethics and death ethic perception in Korean nursing students. The study included 284 nursing students. Data was obtained through convenient sampling, adopting a cross-sectional design methodology. Professional values among nurses were significantly different according to occupational view (p<.001), ethical perception (p<.001) and ethical values (p<.001). Death ethic perception was significantly different based on ethical education (p<.05) and ethical values(p<.05). Positive correlations were found between nursing professional values, bioethics and death ethic perception, death ethic was significant predictors of professional values with an explanatory power of 15.0%. The findings of this study may assist in providing a detailed understanding of values among Korean nursing professionals, bioethics and death ethic perception.

• Korean Journal of Ichthyology
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• v.21 no.4
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• pp.283-286
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• 2009

The egg capsule of Hongeo koreana is newly described based on two egg capsules extracted from the uterus of a female collected near the type locality, the southwestern coast of the Korean Peninsula. The egg capsule of H. koreana has the following characters: medium sized, measuring 124.5~133.7 mm in total length including horns, 102.8~109.4 mm in length excluding horns, and 41.0~42.2 mm in maximum width; asymmetrical, with the egg capsule more convex ventrally in lateral view; the surface relatively smooth, with longitudinal striations distinct, and covered with masses of sticky silky fibers; anterior and posterior aprons distinct; all four horns short, tube-like in shape, elliptical in cross section, anterior horns recurved inwardly; respiratory fissure present at tip of each of the four horns. The color of the fresh capsule is bright brown.

• Journal of Astronomy and Space Sciences
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• v.31 no.1
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• pp.41-50
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• 2014

The Earth is not perfectly spherical and its rotational axis is not fixed in space, and these geophysical and kinematic irregularities work as dominant perturbations in satellite orbit propagation. The International Earth Rotation Service (IERS) provides the Conventions as guidelines for using the Earth's model and the reference time and coordinate systems defined by the International Astronomical Union (IAU). These guidelines are directly applied to model orbital dynamics of Earth satellites. In the present work, the effects of the latest conventions released in 2010 on orbit propagation are investigated by comparison with cases of applying the previous guidelines, IERS Conventions (2003). All seven major updates are tested, i.e., for the models of the precession/nutation, the geopotential, the ocean tides, the ocean pole tides, the free core nutation, the polar motion, and the solar system ephemeris. The resultant position differences for one week of orbit propagation range from tens of meters for the geopotential model change from EGM96 to EGM2008 to a few mm for the precession/nutation model change from IAU2000 to IAU2006. The along-track differences vary secularly while the cross-track components show periodic variation. However, the radial-track position differences are very small compared with the other components in all cases. These phenomena reflect the variation of the ascending node and the argument of latitude. The reason is that the changed models tested in the current study can be regarded as small fluctuations of the geopotential model from the point of view of orbital dynamics. The ascending node and the argument of latitude are more sensitive to the geopotential than the other elements. This study contributes to understanding of the relation between the Earth's geophysical properties and orbital motion of satellites as well as satellite-based observations.

• Restorative Dentistry and Endodontics
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• v.41 no.3
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• pp.182-188
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• 2016

Objectives: The purpose of this study was to evaluate the proximity of the mandibular molar apex to the buccal bone surface in order to provide anatomic information for apical surgery. Materials and Methods: Cone-beam computed tomography (CBCT) images of 127 mandibular first molars and 153 mandibular second molars were analyzed from 160 patients' records. The distance was measured from the buccal bone surface to the root apex and the apical 3.0 mm on the cross-sectional view of CBCT. Results: The second molar apex and apical 3 mm were located significantly deeper relative to the buccal bone surface compared with the first molar (p < 0.01). For the mandibular second molars, the distance from the buccal bone surface to the root apex was significantly shorter in patients over 70 years of age (p < 0.05). Furthermore, this distance was significantly shorter when the first molar was missing compared to nonmissing cases (p < 0.05). For the mandibular first molars, the distance to the distal root apex of one distal-rooted tooth was significantly greater than the distance to the disto-buccal root apex (p < 0.01). In mandibular second molar, the distance to the apex of C-shaped roots was significantly greater than the distance to the mesial root apex of non-C-shaped roots (p < 0.01). Conclusions: For apical surgery in mandibular molars, the distance from the buccal bone surface to the apex and apical 3 mm is significantly affected by the location, patient age, an adjacent missing anterior tooth, and root configuration.

• Journal of the Ergonomics Society of Korea
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• v.36 no.1
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• pp.37-52
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• 2017

Objective: The present study developed a user-centered 3D virtual liver surgery planning (VLSP) system called Dr. Liver to provide preoperative information for safe and rational surgery. Background: Preoperative 3D VLSP is needed for patients' safety in liver surgery. Existing systems either do not provide functions specialized for liver surgery planning or do not provide functions for cross-check of the accuracy of analysis results. Method: Use scenarios of Dr. Liver were developed through literature review, benchmarking, and interviews with surgeons. User interfaces of Dr. Liver with various user-friendly features (e.g., context-sensitive hotkey menu and 3D view navigation box) was designed. Novel image processing algorithms (e.g., hybrid semi-automatic algorithm for liver extraction and customized region growing algorithm for vessel extraction) were developed for accurate and efficient liver surgery planning. Usability problems of a preliminary version of Dr. Liver were identified by surgeons and system developers and then design changes were made to resolve the identified usability problems. Results: A usability testing showed that the revised version of Dr. Liver achieved a high level of satisfaction ($6.1{\pm}0.8$ out of 7) and an acceptable time efficiency ($26.7{\pm}0.9 min$) in liver surgery planning. Conclusion: Involvement of usability testing in system development process from the beginning is useful to identify potential usability problems to improve for shortening system development period and cost. Application: The development and evaluation process of Dr. Liver in this study can be referred in designing a user-centered system.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.5
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• pp.1499-1507
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• 2015

The aim of this study is to research on the recognitions and preferences of Puffer fish consumers with the recently increasing well-being trend. To carry out this research, the main analysis was focused on two specific points: how much consumers perceive swellfish and which kinds of Puffer fish foods are preferred by consumers. Although the consumption of Puffer fish is gradually expending, at the same time, there are also numerous obstructive elements in consuming swellfish. In this regard, this test on Puffer fish food will be able to contribute to show an outlook for the Puffer fish food market in the future and to promote consumption of Puffer fish as well. Methodologically, a statistical research was adopted to find out how people understand Puffer fish and the patterns of their choices and intensive examinations were conducted throughout the collected questionnaire. For a more effective outcome, it was necessary to divide into two groups, the Nation's capital area with Seoul as a center, the most densely populated area and Busan, the biggest marine products consumption area, examining the inclination to consume with regions. In the concrete, the detailed research survey on the Puffer fish were performed with the opinions of the five hundred people from capital area and the five hundred people from Busan area. The difference and common features of consumer's recognition about Puffer fish food were founded through cross analysis according to age, gender, regions, and income. In conclusion, this research showed the difference tastes and recognition standards toward Puffer fish among consumers from Seoul and Busan areas. If it is possible to apply this result to the efforts of improving supplier's understanding about Puffer fish consumers' features and cultivating new Puffer fish items, it could contribute to the further consumption of Puffer fish food in the long term point of view.

• Journal of Korean Elementary Science Education
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• v.35 no.3
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• pp.305-315
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• 2016

The purpose of this paper was to analyze the role of illustrations in elementary textbooks (3~4 grade) of the 2009 revised curriculum of science education in Korea from point of view of aim of science by applying the criteria of 5E inquiry process model for reflecting core aim of the science education. The subjects of the paper was the 105 illustrations in the earth-science domain of elementary science textbooks (3~4 grade) of the 2009 revised curriculum of science education in Korea. The analysis criterion was of two categories, the function of illustration and the role of illustration. the function of illustration was divided into three subcategories such as Exclusiveness type, correspondence type and supplementary type. The role of illustration was divide into five subcategories such as Engagement, Exploration, Explanation, Elaboration and Evaluation. According to results of the illustration analysis are as follows: the result of the function of illustration are exclusiveness type 39, correspondence type 36 and supplementary type 30, the important of point to note is that there are a lot of exclusiveness type considerably. compared with other subjects, this fact indicate character of illustration of the only science textbook. The result of the role of illustration are Engagement 14, exploration 64, explanation 25, elaboration 2 and evaluation 0. This data indicate main role of illustrations in earth-science domain is to help the students to be able to observe and explore. Cross-analysis of the function and role was a significant difference. Role of illustration was evenly distributed within Exclusiveness type on the other hand, the role of illustrations was mainly exploration and explanation in correspondence and supplementary type. Especially, illustration of exploration was mainly correspondence type.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.3
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• pp.768-776
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• 1994

This paper describes computer-aided forging design for rib/web shaped parts. In manufacturing a part by means of forging process, the first step is to design the forging. This is done by modifying the given machined part geometry according to the requirements of the forging process. Traditionally, this is done by experienced forging designers using empirical forging design guidelines. Generally, it would be neither possible nor practical to develop a system which encompasses the design of all types of forgings. Accordingly, forging design can be simplified by considering critical two dimensional cross sections of the machined part geometry. This system is composed of three modules(process variable decision module, forging design module and redesign module) and each module is carried out in regular sequence. In the process variable decision module, first of all, the undercut is checked and modified, and then deep recesses and holes difficult to forge are eliminated. Also parting line, forging plane, forging plan view area, forging weight and maximum size(maximum height or width)are determined. In the forging design module, the magnitude of various allowances, draft angle, minimum web thickness, corner and fillet radius are determined and then geometry modification is performed. Finally, since the design rules and databases used in this system are based on parameters of the forging geometry, such as the trimmed forging plan area, forging weight, forging maxmum size, plausible estimates need to be made for these parameters. Therefore, in the re-design module, the design process is iterated until a satisfactory forging is obtained.