• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.3
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• pp.154-159
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• 2006

It is essential to understand the decomposition characteristics for developing the optimum anaerobic digestion system of organic wastes. In this study, BMP (Biochemical Methane Potential) test using serum bottle was conducted to evaluate the anaerobic degradability of fish offal. 3 different groups of fish offal including waste from mackerel and hairtail handling except viscera and fish viscera were chosen for the substrates. Grinded fish offal was transferred anaerobically to serum bottle in amounts of 50 ml, 100 ml and 150 ml, respectively. BMP test was carried out in triplicate. Cumulative methane production and methane production rate depending on incubation time were evaluated. These results varied depending on substrate characteristics. The average values of ultimate methane yield ranged between $420ml{\cdot}CH_4/g{\cdot}VS$ and $490ml{\cdot}CH_4/g{\cdot}VS$, and the methane production and degradation rate of viscera were higher than those of other parts of fish offal. According to the analysis of elemental composition, average C/N ratio of fish offal used in this study was 5.2. Theoretical ultimate methane yield calculated from elemental composition was $522ml{\cdot}CH_4/g{\cdot}VS$. Biodegradability was calculated as 0.847.

• Journal of Korean Society of Steel Construction
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• v.11 no.4 s.41
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• pp.329-338
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• 1999

A systematic procedure to evaluate fatigue damages and to predict remaining fatigue lives is introduced for a steel railway bridge. Fatigue damages are evaluated by using the currently available fatigue damage theory. Fatigue lives with the condition of fatigue crack initiation are estimated by the probabilistic approach based on the reliability theory as well as the simplified procedure. A equivalent deterministic procedure is also suggested to assess the remaining fatigue life under various traffic conditions. Numerical simulations are used to assess dynamic stress histories with correction factors. Loading models are obtained from the passenger volume data. Train coincidences are also considered. Based on the results, the fatigue life is found to be underestimated by without considering the coincidence of trains on the bridge. The simplified method proposed in this study are found to yield approximately the same results as the systematic procedure.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2016.05a
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• pp.404-430
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• 2016

This study started from the awareness of the issue if the citation index newly introduced to evaluate the quality of papers satisfies the proper timing matter, which is a component of performance indicators for the evaluation of government-funded R&D institutes. Accordingly, the study will propose improvement ways to shift the previous evaluation system to quality evaluation for mission-oriented R&D institutes by analysing and using the periodical characteristics such as citation half-life and immediacy index of papers. As a result, it turned out that the speed of academic change is getting faster in proportion to the dependency on the technological development but that the citation speed in the field of public technology is relatively slower and the speed of knowledge transfer in the fields related to industry is faster. In addition, the citation index among the R&D fields showed no differences, and the minimum period for citation index measurement with validity should be over 6 years. The problems of evaluation for mission-oriented R&D institutes were deducted based on the technical and statistical analysis results of the temporal characteristic of citation necessary for quality evaluation of performance among R&D fields. To solve the problems, policy alternatives for object and valid quality evaluation were proposed from the points of evaluation period, evaluation criteria, and evaluation management.

• Journal of KIISE:Software and Applications
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• v.37 no.3
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• pp.185-193
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• 2010

With the emergence of ubiquitous computing era, various models for providing personalized service have been proposed, and, especially, several recommendation service schemes have been proposed to give tailored services to users proactively. However, the previous recommendation service schemes utilize a wide range of data without and filtering and consider the limited context-aware information to predict user preferences so that they are not adequate to provide personalized service to users. In this paper, we propose an adaptive recommendation service scheme which proactively provides suitable services based on the current context. We use accumulated interaction contexts (IC) between users and devices for predicting the user's preferences and recommend adaptive service based on the current context by utilizing clustering and collaborative filtering. The clustering algorithm improves efficiency of the recommendation service by focusing and analyzing the data that is collected from the locations nearby the users. Collaborative filtering guarantees an accurate recommendation, even when the data is insufficient. Finally, we evaluate the performance and the reliability of the proposed scheme by simulations.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.2
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• pp.21-28
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• 2008

This paper proposes a novel reduced-reference assessment method for video quality assessment, in which one-dimensional (1-D) histograms of motion vectors (MVs) are used as features of videos. The proposed method is more efficient than the conventional methods in view of computation time, because the proposed quality metric decodes MVs directly from video stream in the parsing process instead of reconstructing the distorted video at the receiver. Moreover, in view of data size, the propose method is efficient because a sender transmits 1-D histograms of MVs accumulated over whole input video sequences. Here, we use 1-D histograms of MVs accumulated over the whole video sequences, which is different from the conventional methods that assessed each image independently. For testing the similarity between histograms, we use histogram intersection and histogram difference methods. We compare the proposed method with the conventional methods for 52 video clips, which are coded under varying bit rate, image size, and frame rate. Experimental results show that the proposed method is more efficient than the conventional methods and that the proposed method is more similar to the mean opinion score (MOS) than conventional algorithms.

• Korean Journal of Ecology and Environment
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• v.55 no.1
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• pp.60-75
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• 2022

The Bayesian algorithm model is a model algorithm that calculates probabilities based on input data and is mainly used for complex disasters, water quality management, the ecological structure between living things or living-non-living factors. In this study, we analyzed the main factors affected Korean Estuary Trophic Diatom Index (KETDI) change based on the Bayesian network analysis using the diatom community and physicochemical factors in the domestic estuarine aquatic ecosystem. For Bayesian analysis, estuarine diatom habitat data and estuarine aquatic diatom health (2008~2019) data were used. Data were classified into habitat, physical, chemical, and biological factors. Each data was input to the Bayesian network model (GeNIE model) and performed estuary aquatic network analysis along with the nationwide and each coast. From 2008 to 2019, a total of 625 taxa of diatoms were identified, consisting of 2 orders, 5 suborders, 18 families, 141 genera, 595 species, 29 varieties, and 1 species. Nitzschia inconspicua had the highest cumulative cell density, followed by Nitzschia palea, Pseudostaurosira elliptica and Achnanthidium minutissimum. As a result of analyzing the ecological network of diatom health assessment in the estuary ecosystem using the Bayesian network model, the biological factor was the most sensitive factor influencing the health assessment score was. In contrast, the habitat and physicochemical factors had relatively low sensitivity. The most sensitive taxa of diatoms to the assessment of estuarine aquatic health were Nitzschia inconspicua, N. fonticola, Achnanthes convergens, and Pseudostaurosira elliptica. In addition, the ratio of industrial area and cattle shed near the habitat was sensitively linked to the health assessment. The major taxa sensitive to diatom health evaluation differed according to coast. Bayesian network analysis was useful to identify major variables including diatom taxa affecting aquatic health even in complex ecological structures such as estuary ecosystems. In addition, it is possible to identify the restoration target accurately when restoring the consequently damaged estuary aquatic ecosystem.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.3
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• pp.371-377
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• 2007

In this paper, acceleration threshold of perception for the horizontal vibration of tall buildings was estimated. Excessive vibration of tall buildings by wind can give displeasure, such as giddiness and visual insecurity. To provide comfortable environment to residents of tall buildings, acceleration needs to be limited. For tall buildings the first mode of vibration is dominant. To reproduce the first mode of vibration, experiments were performed by generating sine waves by a shaking table. A nitration house was made and forty persons were employed for experiments. The forty persons were organized into five experimental groups, each of which was composed of eight persons, and the threshold of perception for horizontal vibration was measured by increasing acceleration in the range of 0.2Hz through 1.2Hz of frequency, Performance curves were obtained by dividing the distribution of perception for horizontal vibration into the range of $0{\sim}20%,\;21{\sim}40%,\;41{\sim}60%,\;61{\sim}80%\;and\;81{\sim}100%$ and by fitting curves.

• Journal of Wetlands Research
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• v.20 no.4
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• pp.383-389
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• 2018

Recently, it has been reported that water pollution due to non-point pollutants continues. Studies have been actively carried out to prevent such non-point pollutants from flowing into the water system and to prevent water pollution. In this study, to evaluate the adequate design of the LID facilities the rainfall corresponding to 80% of the cumulative rainfall of Yongin city was applied to an SA / CA graph obtained from the analysis of monitoring results of the vegetation type LID facility. As a result, the appropriate SA/CA ratio was 0.6% for stormwater sustain efficiency 80% and the appropriate SA/CA ratio was 0.5% for TSS removal efficiency 80%. The appropriate SA/CA ratio of the vegetation type LID proposed in this study can be used as a basis. for the future vegetation type LID design. If more data of vegetation type LID are added through continuous research, it will be more accurate.

• Journal of Korea Technology Innovation Society
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• v.19 no.4
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• pp.768-798
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• 2016

This study started from the awareness of the issue if the citation index newly introduced to evaluate the quality of papers satisfies the proper timing matter, which is a component of performance indicators for the evaluation of government-funded R&D institutes. Accordingly, the study will propose improvement ways to shift the previous evaluation system to quality evaluation for mission-oriented R&D institutes by analysing and using the periodical characteristics such as citation half-life and immediacy index of papers. As a result, it turned out that the speed of academic change is getting faster in proportion to the dependency on the technological development but that the citation speed in the field of public technology is relatively slower and the speed of knowledge transfer in the fields related to industry is faster. In addition, the citation index among the R&D fields showed no differences, and the minimum period for citation index measurement with validity should be over 6 years. The problems of evaluation for mission-oriented R&D institutes were deducted based on the technical and statistical analysis results of the temporal characteristic of citation necessary for quality evaluation of performance among R&D fields. To solve the problems, policy alternatives for object and valid quality evaluation were proposed from the points of evaluation period and evaluation criteria.

• Journal of Radiation Protection and Research
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• v.26 no.1
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• pp.19-26
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• 2001

In order to assess the atmospheric dispersion for the accidental releases of nuclear power plants, in calculating X/Q values in the XOQAR and PAVAN codes which are based on Reg. Guide 1.145, the X/Q and frequency values are plotted on log-normal paper. Starting with the highest X/Q value of this plot, the codes compare the slope of the line drawn from this point to every other point within an increment containing ten X/Q values. If there are fewer than ten values, only the number available are used. The coefficients that produce the line with the least negative slope are saved. The end point of this line is used as the next starting point, from which slopes to the points within the next increment, containing ten X/Q values, are compared. The X/Q values corresponding to the cumulative frequency values 0.5%, 5% or 50% are calculated to search for the $0{\sim}2$ hour X/Q value that tends to be a very conservative value. In this work, a fuzzy logic inference method is used for nonlinear interpolation of the X/Q values versus the cumulative frequency. The fuzzy logic inference method is known to be a food technique for nonlinear interpolation. The proposed method was applied to a potential accidential radioactive release of the Yonggwang nuclear power plant, which gives more realistic X/Q values.