• Journal of Navigation and Port Research
• /
• v.40 no.4
• /
• pp.165-171
• /
• 2016

SEEMP (Ship Energy Efficiency Management Plan) has entered into force since 2013 for the reduction of GHG emission of operating ships. SEEMP guidelines include the hardware modification or installation of energy-saving device on ship. It also includes software based energy-saving technology such as optimum routing, speed optimization, etc. Hardware based technologies are not easy to apply to ongoing vessel due to the operational restriction. Therefore, IT based energy-saving technology was applied and its energy efficiency was evaluated using before and after energy-saving system applied voyage data. SEEMP advises a voluntary participation of EEOI (Ship Energy Efficiency Operation Indicator) use as an indicator of ship energy efficiency operation, and those results were also shown to evaluate the improvement efficiency of energy-saving system.

• Journal of Advanced Marine Engineering and Technology
• /
• v.41 no.4
• /
• pp.316-322
• /
• 2017

The primary objective of the current study is to develop outstanding hull form on resistance performance by using numerical analysis code. Model tests were conducted to assess the resistance performance of the developed hull form. The investigation of an existing vessel was performed for validating the actual ship design based on the drawing. The operating displacement and speed were mainly confirmed through investigation of the existing vessel. The resistance performance of the existing vessel was analyzed using numerical code. The developed vessel was derived through studies on wave improvement of the bow shoulder, the balance of displacement distribution, the modification of the frame shape, and the size and shape change of the center skeg. Based on the results of a computational fluid dynamics analysis, the resistance performance of the developed vessel showed an improvement of 15% over the existing vessel at a speed of 11 knots. Resistance tests were conducted to evaluate the performance of the existing vessel and the developed vessel in the towing tank. Finally, the effective horsepower of the developed vessel showed an improvement of 17% over the existing vessel.

• Journal of KIISE:Computer Systems and Theory
• /
• v.27 no.4
• /
• pp.362-372
• /
• 2000

The causal message logging is a low-cost technique of building a distributed system that can tolerate process crash failures. Previous research in causal message logging protocol assumes that the number of processes in a fault-tolerant system is fixed. This assumption makes all processes modify their data structures when a new process is added or an existing process terminates. However, the proposed approach in this paper allows to each process retain identifiers of only the communicating processes instead of all processes. This mechanism enables the fault-tolerant system to operate at many different scales. Using this mechanism, we develop a new algorithm that can be adapted for recovery in existing causal message logging protocols. Our recovery algorithm is 1) a distributed technique which does not require recovery leader, 2) a nonblocking protocol which does not force live processes to block while recovery is in progress, and 3) a novel mechanism which can tolerate failures of an arbitrary number of processes. Earlier causal message logging protocols lack one or more of the above properties.

• Journal of the Korean Society for Computer Game
• /
• v.31 no.4
• /
• pp.185-195
• /
• 2018

As virtual reality technology has gained popularity from people, various contents have appeared. Virtual reality game making good use of virtual reality device has received lots of attention from users and market. A number of virtual reality games have been developed. Virtual reality game allows users to feel presence and flow to be maximized through virtual reality device. A user can interact with several items through interface of device in display environment of virtual reality. This study was find a way to arouse an interest and induce users to be immersed in virtual reality game by maximizing above mentioned characteristics. This study was analyze interaction items in popular virtual reality game and interface design methods before presenting design methods. This study was make a comparative analysis of interface design methods centering on virtual reality game cases and examine a link between interface and interaction items. Through this study, it is expected that this will be a prior study that will be the basis for designing interfaces for virtual reality games that are more presence.

• Journal of Korean society of Dental Hygiene
• /
• v.19 no.5
• /
• pp.731-742
• /
• 2019

Objectives: To analyze the association between sleep duration and the number of remaining teeth in people aged 65 years or older in order to provide basic data for improving sleep quality and developing oral health programs for teeth maintenance. Methods: The raw data for the analysis were obtained from the sixth Korean National Health and Nutrition Examination Survey (KNHANES) dataset, conducted between 2013 and 2015. The 4,340 subjects included in the study underwent oral examinations and then proceeded to answer related questions. The collected data were analyzed using SPSS (ver 23.0) program via composite samples, with the calculations for mean, standard deviation, chi-square test, and logistic return analysis being performed. Results: An analysis of the effect of sleep duration on the number of remaining teeth among people aged >65 years old showed that if the confounding variables were not corrected for, the risk of having less than 9 hours of sleep was 1.40 times higher (95% CI: 1.06-1.86). However, this was not statistically significant in models that corrected for gender, age, and other confounding variables (p>0.05). Conclusions: The association between sleep duration among the elderly with their number of remaining teeth was confirmed. Therefore, measures to improve sleep quality and oral care practices to maintain the remaining teeth in people over 65 years old should be developed.

• Journal of Korean Society of Forest Science
• /
• v.77 no.1
• /
• pp.10-16
• /
• 1988

This study was carried out to estimate the aboveground-biomass of Machilus thunbergii, warm-temperature evergreen broad leaved tree, growing in the seashore near Bogil island located at the southern part of the Korean peninsula. The bark of M. thunbergii was used for medicine in the Korea. The results were summarized as follows : 1) The aboveground-biomass was 123.708 tons/ha and the biomass of branch bark greater than 3cm in branch diameter was 1/5 of total bark mass(8.095 tons/ha). Dry matter density was $1.77ha/m^3$ and leaf area index 8.08. 2) Net production of the stand was estimated as 16.051 tons/ha/yr and the leaf was the greatest, followed by stemwood, branchwood, stem-bark and branch-bark. 3) The net assimilation rate of the stand was 1.384 kg/kg/yr. The efficiency of leaves to produce stem was 0.451 kg/kg/yr and that of bark 0.051 kg/kg/yr. Biomass accumulation ratio was 7.707 kg/kg/yr.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.31 no.2
• /
• pp.217-225
• /
• 1998

This study was performed to compare the effects of a fish cage on the structure of meiobenthic communities at two locations during May, 1996. The number of meiofaunal taxa at the existing cage site and control site was 15 and 26, respectively. Nematoda was the most dominant group of meiobenthos. Nematoda and Sarcomastigophora comprised more than $90\%$ of total meiofauna at both sites. The total density of control site was 7,702 inds./$10\;cm^{2}$ which is 10 times more than that of fish cage site. The density was highest in the upper 1 cm and decreased with sediment depth. The nematodes/harpacticoid copepods ratio as an index of pollution monitoring for benthic ecosystem at fish cage site was two times higher than at control site. Kinorhyncha known to be sensitive to pollution stress was not found at fish cage site.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.15 no.4
• /
• pp.219-233
• /
• 2013

We employed the ecological niche modeling framework using GARP (Genetic Algorithm for Ruleset Production) to model the current and future geographic distribution of Pinus densiflora based on environmental predictor variable datasets such as climate data including the RCP 8.5 emission climate change scenario, geographic and topographic characteristics, soil and geological properties, and MODIS enhanced vegetation index (EVI) at 4 $km^2$ resolution. National Forest Inventory (NFI) derived occurrence and abundance records from about 4,000 survey sites across the whole country were used for response variables. The current and future potential geographic distribution of Pinus densiflora, one of the tree species dominating the present Korean forest was modeled and mapped. Future models under RCP 8.5 scenarios for Pinus densiflora suggest large areas predicted under current climate conditions may be contracted by 2090 showing range shifts northward and to higher altitudes. Area Under Curve (AUC) values of the modeled result was 0.67. Overall, the results of this study were successful in showing the current distribution of major tree species and projecting their future changes. However, there are still many possible limitations and uncertainties arising from the select of the presence-absence data and the environmental predictor variables for model input. Nevertheless, ecological niche modeling can be a useful tool for exploring and mapping the potential response of the tree species to climate change. The final models in this study may be used to identify potential distribution of the tree species based on the future climate scenarios, which can help forest managers to decide where to allocate effort in the management of forest ecosystem under climate change in Korea.

• The Korean Journal of Archival Studies
• /
• no.14
• /
• pp.53-89
• /
• 2006

The historical value of the official documents of the Government General of Choson preserved as permanent archived documents has long been recognized. However, the fact that only parts of the overall documents were preserved and that the contents of the existing documents is not uniform, results in many problems regarding the evaluation and usage of such documents as archives. This study attempts to appraise a series of archival documents related to urban district planning compiled during the colonial era. Although limited in terms of its applicability to the development of an evaluation method for the official documents of the Government General of Choson as a whole, by evaluating the value of these documents based on the background of the documents produced during the Government General of Choson's implementation of its colonial policy, this study provides an important indicator of how such documents should be used in the future. On the other hand, the assessment of historical records such as the official documents of the Government General of Choson which have already been designated and preserved as permanent archived documents should not be perceived as an attempt to dispose of the relevant documents. With regard to the appraisal of historical archives, it is necessary to consider measures to link such documents with existing databases or information contents in order to heighten access to and usage of the relevant documents in the future.

• The Korean Journal of Archival Studies
• /
• no.54
• /
• pp.179-210
• /
• 2017

By redefining the concept of history, my colleagues and I have reformed our department in terms of curriculum and faculty members. This paper is a report of some of the conclusions that we have obtained from this procedure. Despite a long relationship, two disciplines do not seem to match or complement each other in the Korean education system. We believe that this is due to the fact that the Department of Korean History has focused on "national history (NH)." By conferring a privilege on NH, persons, families, societies, regions, and others were removed from NH. To make matters worse, a biased view that history is just an interpretation has prevailed, and the empiricism of history was weakened, which brought about an indifference in keeping records and archives. In East Asia, "history" means both modern history and archives. The concern about the authenticity of records did not come from H. Jenkinson or L. Duranti, and not even from the electronic environment or the Public Records Act of 1998. Key concepts such as records, documents-archives, manuscripts, authenticity, compilation-appraisal, arrangement, and description are different from their signifiant but are same or similar to their $signifi{\acute{e}}$. In case of "provenance" and "original order," they are used in education and practice in the traditional archives. History includes the recording, archiving, and the story or historiography of an event. In this context, the Department of Korean History should contain a more archives-oriented curriculum and select an archival-trained faculty. On the other hand, the department has accumulated long-term experience with appraisal and description of records; thus, archival science should absorb the criticism of the material. History will be shaken without the help of archives, while archives will lose their root without history. We are at the point in which we need to be reminded why we want to be a historian or an archivist, and for this, the more colleagues, the better.