• Journal of Korean Society of Environmental Engineers
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• v.32 no.6
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• pp.639-648
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• 2010

The optimal conditions for the analysis of BPA by HPLC-MS/MS was investigated and the ultrasound degradation capacity of the BPA, with the goal to establish the proper directions for analyzing infinitesimal quantities of BPA by HPLC-MS/MS was examined. The MDL and LOQ of BPA analyzed by HPLC-MS/MS were measured 0.13 nM and 1.3 nM respectively, its sensitivity about 620 and 32 times greater than HPLC-UV (MDL: 81.1 nM, LOQ: 811 nM) and FLD (MDL: 4.6 nM, LOQ: 46 nM). In other words, the new method enables the analysis of BPA with the accuracy up to one 1,180th of the amount specified in U.S. EPA guideline for drinking water. Degradation rate of BPA by ultrasound measured over 95% under 580 kHz and 1000 kHz frequency within 30 minutes of treatment, whereas the rate showed some decrease at 28 kHz frequency. At 580 kHz of ultrasound has proven to be the most effective among others at degradation rate and $k_1$ value, so we concluded that this frequency of ultrasound creates hospitable condition for the combined process of degradation by pyrolysis and oxidization. With the addition of 0.01 mM of $CCl_4$, BPA with the initial concentration of 1 ${\mu}M$ was degraded by more than 98% within 30 minutes, the $k_1$ value measured 5 minutes and 30 minutes into the experiment both showed increases by 1.4 and 1.1 times, respectively, compared with BPA without $CCl_4$. It is also found that the main degradation mechanism of BPA by ultrasound is oxidization process by OH radical, based on the fact that the addition of 10 mM of t-BuOH decreased the rate of BPA degradation by around 60%. However, 33% of BPA degradation rate obtained with the addition of t-BuOH implies further degradation done by pyrolysis or other sorts of radical beside OH radical.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.4
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• pp.242-255
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• 2006

In the recent years, Popularization of mobile devices such as Smart Phones, PDAs and MP3 Players causes rapid increasing necessity of Power management technology because it is most essential factor of mobile devices. On the other hand, despite low price, hard disk has large capacity and high speed. Even it can be made small enough today, too. So it appropriates mobile devices. but it consumes too much power to embed In mobile devices. Due to these motivations, in this paper we had suggested methods of minimizing Power consumption while playing multimedia data in the disk media for real-time and we evaluated what we had suggested. Strict limitation of power consumption of mobile devices has a big impact on designing both hardware and software. One difference between real-time multimedia streaming data and legacy text based data is requirement about continuity of data supply. This fact is why disk drive must persist in active state for the entire playback duration, from power management point of view; it nay be a great burden. A legacy power management function of mobile disk drive affects quality of multimedia playback negatively because of excessive I/O requests when the disk is in standby state. Therefore, in this paper, we analyze power consumption profile of disk drive in detail, and we develop the algorithm which can play multimedia data effectively using less power. This algorithm calculates number of data block to be read and time duration of active/standby state. From this, the algorithm suggested in this paper does optimal scheduling that is ensuring continual playback of data blocks stored in mobile disk drive. And we implement our algorithms in publicly available MPEG player software. This MPEG player software saves up to 60% of power consumption as compared with full-time active stated disk drive, and 38% of power consumption by comparison with disk drive controlled by native power management method.

• Journal of Intelligence and Information Systems
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• v.26 no.1
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• pp.23-45
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• 2020

Big data is creating in a wide variety of fields such as medical care, manufacturing, logistics, sales site, SNS, and the dataset characteristics are also diverse. In order to secure the competitiveness of companies, it is necessary to improve decision-making capacity using a classification algorithm. However, most of them do not have sufficient knowledge on what kind of classification algorithm is appropriate for a specific problem area. In other words, determining which classification algorithm is appropriate depending on the characteristics of the dataset was has been a task that required expertise and effort. This is because the relationship between the characteristics of datasets (called meta-features) and the performance of classification algorithms has not been fully understood. Moreover, there has been little research on meta-features reflecting the characteristics of multi-class. Therefore, the purpose of this study is to empirically analyze whether meta-features of multi-class datasets have a significant effect on the performance of classification algorithms. In this study, meta-features of multi-class datasets were identified into two factors, (the data structure and the data complexity,) and seven representative meta-features were selected. Among those, we included the Herfindahl-Hirschman Index (HHI), originally a market concentration measurement index, in the meta-features to replace IR(Imbalanced Ratio). Also, we developed a new index called Reverse ReLU Silhouette Score into the meta-feature set. Among the UCI Machine Learning Repository data, six representative datasets (Balance Scale, PageBlocks, Car Evaluation, User Knowledge-Modeling, Wine Quality(red), Contraceptive Method Choice) were selected. The class of each dataset was classified by using the classification algorithms (KNN, Logistic Regression, Nave Bayes, Random Forest, and SVM) selected in the study. For each dataset, we applied 10-fold cross validation method. 10% to 100% oversampling method is applied for each fold and meta-features of the dataset is measured. The meta-features selected are HHI, Number of Classes, Number of Features, Entropy, Reverse ReLU Silhouette Score, Nonlinearity of Linear Classifier, Hub Score. F1-score was selected as the dependent variable. As a result, the results of this study showed that the six meta-features including Reverse ReLU Silhouette Score and HHI proposed in this study have a significant effect on the classification performance. (1) The meta-features HHI proposed in this study was significant in the classification performance. (2) The number of variables has a significant effect on the classification performance, unlike the number of classes, but it has a positive effect. (3) The number of classes has a negative effect on the performance of classification. (4) Entropy has a significant effect on the performance of classification. (5) The Reverse ReLU Silhouette Score also significantly affects the classification performance at a significant level of 0.01. (6) The nonlinearity of linear classifiers has a significant negative effect on classification performance. In addition, the results of the analysis by the classification algorithms were also consistent. In the regression analysis by classification algorithm, Naïve Bayes algorithm does not have a significant effect on the number of variables unlike other classification algorithms. This study has two theoretical contributions: (1) two new meta-features (HHI, Reverse ReLU Silhouette score) was proved to be significant. (2) The effects of data characteristics on the performance of classification were investigated using meta-features. The practical contribution points (1) can be utilized in the development of classification algorithm recommendation system according to the characteristics of datasets. (2) Many data scientists are often testing by adjusting the parameters of the algorithm to find the optimal algorithm for the situation because the characteristics of the data are different. In this process, excessive waste of resources occurs due to hardware, cost, time, and manpower. This study is expected to be useful for machine learning, data mining researchers, practitioners, and machine learning-based system developers. The composition of this study consists of introduction, related research, research model, experiment, conclusion and discussion.

• Horticultural Science & Technology
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• v.30 no.5
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• pp.484-492
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• 2012

The present study aimed to investigate the effect of static magnetic field (SMF) on the growth and physiological characteristics of common indoor plant species. Five foliage plant species, Spathiphyllum spp., Ardisia pusilla DC., Syngonium podophyllum, Peperomia pereskiifolia, and Pilea cadierei were potted into plastic pot equipped with round type anisotropic sintered NdFeB permanent magnet inside the pot. The surface magnetic flux density of each magnet was 3,500 G. After 6 months of growth period, the biomass accumulations of Spathiphyllum, A. pusilla, and P. cadierei under SMF were statistically higher than those of controls. Tissue water content also increased under the influence of SMF in most species. The photosynthetic rate of Spathiphyllum under SMF significantly increased but other species showed no significant difference compared with control. Although there was no significant increase in the photosynthetic rates of A. pusilla, and P. cadierei, they showed remarkable increase in total fresh weight under SMF. This suggests that the demand of assimilates for normal metabolism could be decreased under magnetic influence and thereby biomass accumulation could be more favored. But this is not always true for all plant species because P. pereskiifolia in this experiment, showed no changes in both photosynthetic rate and biomass accumulation. Leaf nitrogen and chlorophyll contents were enhanced significantly in most plant species under influence of SMF. Chlorophyll a/b ratio also increased by SMF. Although there might be a limitation depending on plant species, these results suggest that long-term exposure to SMF might allow plant to have an enhanced acclimation capacity against environmental fluctuations and optimal application of SMF could increase the practical use of indoor plants such as an attempt to improve indoor air quality.

• Journal of Animal Environmental Science
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• v.17 no.sup
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• pp.61-68
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• 2011

To assess the total cost with all stages of facilities, the feasibility of Life Cycle Cost (LCC) analysis was examined in this study to estimate the livestock manure treatment system and optimal decision making process. For the economic evaluation, the plant/equipment investment and annual operation cost of four Public Livestock Recycling Facilities, whose treatment capacity is 100 ton piggery manure per day, was compared. The initial cost was in the range of 2,699 million won to 3,202 million won, where T and E methods were highest and lowest, respectively. The annual operation cost was in the level of 378 million to 498 million won, which decreased in the following order : T method > J method > E method > B method. For the LCC analysis, 4.7% of interest rate, 3.13% of inflation rate, and 1.52% of net discount rate was considered by the data received from Bank of Korea and Statics Korea in the period of 2000 to 2009. Also, for the calculation of present value factor, the durable years of civil engineering & construction, machinery and electric instrument was 30 years, 10 years and 15 years, respectively. Based on these consideration, operation cost was in the range of 17,570 won/ton to 20,661 won/ton, and E method (17,570 won/ton) was economical and B method (20,661 won/ton) was non-economical. Though initial cost of T method was higher than that of B method, LCC analysis of T method was lower than that of T method due to the lower operation cost. Therefore, LCC analysis, which considers both initial cost and operation cost, is more reasonable evaluation method than either initial cost or annual operation cost. For the change of LCC analysis according to the uncertainty, the sensitivity analysis was carried out using fluctuation magnitude of discount rate in the period of 2000 to 2009. As a result, LCC analysis evaluated by discount rate was stable for the uncertain factors since the cost leadership did not change even though the sensitivity analysis varied. In summary, the economic evaluation using LCC analysis could be an efficient reference to choose the suitable livestock manure treatment plants. Furthermore, standardization of statement calculation for the actual cost analysis should be conducted and more detailed study is necessary to validate this summary. Therefore, the application of comprehensive technology evaluation, which considers LCC analysis, should contribute in obtaining objectivity and enhancing reliability for the 'Evaluation of Livestock Manure Treatment System and its Technology'.

• Journal of the Korean Institute of Navigation
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• v.13 no.1
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• pp.21-53
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• 1989

In the past twenty years, there has been a rapid increase in the volume of traffic in Korea due to the Korean great growth of the Korean economy. Since transformation provides an infrastructure vital to economic growth, it becomes more and more an integral part of the Korea economy. The importance of coastal shipping stands out in particular, not only because of the expansion limit on the road network, but also because of saturation in the capacity of rail transportation. In spite of this increase and its importance, coastal shipping is falling behind partly because it is givenless emphasis than ocean-going shipping and other inland transportation systems and partly because of overcompetition due to excessive ship tonnage. Therefore, estimating and planning optimum ship tonnage is the first take to develop Korean coastal shipping. This paper aims to estimate the optimum coastal ship tonnage by computer simulation and finally to draw up plans for the ship tonnage balance according to supply and demand. The estimation of the optimum ship tonnage is peformed by the method of Origin -Destimation and time series analysis. The result are as follows : (1) The optimum ship tonnage in 1987 was 358, 680 DWT, which is 54% of the current ship tonnage (481 ships, 662, 664DWT) that is equal to the optimum ship tonnage in 1998. this overcapacity result is in excessive competition and financial difficulties in Korea coastal shipping. (2) The excessive ship tonnage can be broken down into ship types as follows : oil carrier 250, 926 DWT(350%), cement carrier 9, 977 DWT(119%), iron material/machinery carrier 25, 665 DWT(117%), general cargo carrier 17, 416DWT(112%). (3) the current total ship crew of 5, 079 is more than the verified optimally efficient figure of 3, 808 by 1271. (4) From the viewpoint of management strategy, it is necessary that excessive ship tonnage be reduced and uneconomic outdated vessels be broken up. And its found that the diversion into economically efficient fleets is urgently required in order to meet increasing annual rate in the amounts of cargo(23, 877DWT). (5) The plans for the ship tonnage balance according to supply and demand are as follows 1) The establishment of a legislative system for the arrangement of ship tonnage. This would involve; (a) The announcement of an optimum tonnage which guides the licensing of cargo vessels and ship tonnage supply. (b) The establishment of an organization that substantially arrangement tonnage in Korea coastal shipping. 2) The announcement of an optimum ship tonnage both per year and short-term that guides current tonnage supply plans. 3) The settlement of elastic tariffs resulting in the protect6ion of coastal shipping's share from other tonnage supply plans. 4) The settlement of elastic tariffs resulting in the protection of coastal shipping's share from other transportation systems. 4) Restriction of ocean-going vessels from participating in coastal shipping routes. 5) Business rationalization of coastal shipping company which reduces uneconomic outdated vessels and boosts the national economy. If we are to achieve these ends, the followings are prerequisites; I) Because many non-licensed vessels are actually operating and threatening the safe voyage of the others in Korea coastal routes, it is necessary that those ind of vessels be controlled and punished by the authorities. II) The supply of ship tonnage in Korean coastal routes should be predently monitored because most of the coastal vessels are to small to be diverted into ocean-going routes in case of excessive supply. III) Every ship type which is engaged in coastal shipping should be specialized according to the characteristics of its routes as soon possible.

• Journal of the Mineralogical Society of Korea
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• v.25 no.4
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• pp.185-195
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• 2012

Due to the high reduction and sorption capacity as well as the large specific surface area, nanosized mackinawite (FeS) is useful in reductively transforming chlorinated organic pollutants and sequestering toxic metals and metalloids. Due to the dynamic nature in its colloid stability, however, nanosized FeS may be washed out with the groundwater flow or result in aquifer clogging via particle aggregation. Thus, these nanoparticles should be modified such as to be built into permeable reactive barriers. This study employed coating methods in efforts to facilitate the installation of permeable reactive barriers of nanosized mackinawite. In applying the methods, nanosized mackinawite was coated on non-treated silica sand (NTS) and chemically treated silica sand (CTS). For both silica sands, the maximum coating of mackinawite occurred around pH 5.4, the condition of which was governed by (1) the solubility of mackinawite and (2) the surface charge of both silica and mackinawite. Under this pH condition, the maximum coating by NTS and CTS were found to be 0.101 mmol FeS/g and 0.043 mmol FeS/g respectively, with such elevated coatings by NTS likely linked with impurities (e.g., iron oxides) on its surface. Arsenite sorption experiments were performed under anoxic conditions using uncoated silica sands and those coated with mackinawite at the optimal pH to compare their reactivity. At pH 7, the relative sorption efficiency between uncoated NTS and coated NTS changed with the initial concentration of arsenite. At the lower initial concentration, uncoated NTS showed the higher sorption efficiency, whereas at the higher concentration, coated NTS exhibited the higher sorption efficiency. This could be attributed to different sorption mechanisms as a function of arsenite concentration: the surface complexation of arsenite with the iron oxide impurity on silica sand at the low concentration and the precipitation as arsenic sulfides by reaction with mackinawite coating at the high concentration. Compared to coated NTS, coated CTS showed the lower arsenite removal at pH 7 due to its relatively lower mackinawite coating. Taken together, our results indicate that NTS is a more effective material than CTS for the coating of nanosized mackinawite.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.4
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• pp.339-351
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• 1985

This study was carried out to investigate the optimal conditions for meat paste production with sardine. To improve the gel forming ability of meat paste, washing time and condition with alkaline solution, setting time and temperature, and heating temperature before pasteurization were controlled, and the influences of the freshness of raw sardine and the mixing ratios of ordinary and dark muscles on the duality of the meat paste product were discussed. The frozen storage showed a predominant effect on keeping freshness of raw sardine at different storage conditions and gel forming ability was maintained for 1 day at ice storage, for 3 days at $-3^{\circ}C$ and for 4 days at frozen condition, but there was no effect on keeping freshness of raw sardine in the storage at $25^{\circ}C$. Gel strength of meat paste product tended to decrease with washing time of raw meat, and in case of washing 3 times the meat appeared excellent in gel strength, but in case of seven and nine times the meat showed lower water holding capacity and decreased organoleptic test score in the quality of meat paste prtoduct. Raw meat washed with alkaline solution showed a desirable effect on gel forming ability compared with that washed with tap water, and in the case of washed with $0.5\%$ sodium bicarbonate solution exhibited the most favorable effect on gel forming. The gel strength of the meat paste product decreased with the increase of mixing ratios of dark muscle in the raw meat. Setting time and temperature for the gel forming ability of meat paste were good at $5^{\circ}C$ for 20 hours and at $20^{\circ}C$ for 2 hours. In the heating temperature of meat paste, heating treatment at $90^{\circ}C$ was desirable for gel forming.

• Journal of Korea Water Resources Association
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• v.48 no.12
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• pp.1065-1075
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• 2015

In the estuary where the structure such as river-mouth weir has been installed, the flow is developed very complicatedly due to river water from upstream, tide of the sea and floodgate operation. Especially, if basin outlets more than one exists in one estuary, the boundary conditions will be significantly more complex form. Saemangeum(SMG) project area in Korea is the most typical example. There are Mankyung river and Dongjin river in upstream. The water of them inflows into SMG project area. In the downstream, river flow was drained from inland to sea over the SMG sea dike through the sluice. The connecting channel was located between Mankyung and Dongjin basins. It functions not only as transportation by ship in ordinary period but also as flood sharing by sending flood flow to each other in flood period. Therefore, in order to secure the safety against flood, it is very important to understand the flood sharing capacity for connecting channel. In this study, the flood control effect was analyzed using numerical simulation. Delft3D was used to numerical simulation and simulated period was set up with neap tide, in which the maximum flood stage occurred due to poor drainage. Actually, three connecting channels were designed in land use plan of the SMG Master Plan, but they were simplified to a single channel for conciseness of analysis in this study. According to the results of numerical analysis, the water level difference between two basins was increased and the maximum flood stage at dike sluice was also upraised depending on decrease of conveyance. And the velocity induced by same water level difference was decreased when the conveyance became smaller. In certain conveyance above, there was almost no flood control effect. Therefore, if the results of this study are considered for design of connecting channel, it will be expected to draw the optimal conveyance for minimizing dredging construction cost while maximizing the flood control effect.

• Journal of Animal Science and Technology
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• v.47 no.5
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• pp.783-788
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• 2005

This study was conducted to investigate the optimal CP level in growing goat kids. Forty male goats were divided into four treatment groups fed diets containing CP 12, 14, 16, and 18% of concentrate feed, and rice straw, respectively. Results are summarized as follows. Average daily gain’s(ADG) of groups fed diets with CP 14% and CP 18% were 84.0 and 83.0g/d each, which were higher than group fed diets with CP 12% grown at 69.2g of ADG(P<0.05). Daily feed intakes of concentrate and rice straw were 590g and 45g each and there was no difference found between treatments. The amounts of feed required for body weight gain(g) were similar in the range of 7.0-7.3 for groups fed diets with CP 14%, 16% or 18%. But the group fed diets with CP 12% required somewhat more feed for gain at 8.8g. Dressing percentage of groups fed diet with CP 12% was 61.7%, which was higher than groups fed diets with CP 14% or CP 18%(P<0.05) but similar to that fed diet with CP 16%. Meat percentage from goats fed diet with CP 16% was 51.7%, which were higher than goats fed diets with CP 12% or CP 14%(P<0.05). Fat deposition of CP 12% group was higher than the other groups(P<0.05). Percentage of bone weight averaged 17.0% without any difference among treatment groups. Shear force and cooking loss, which are physical properties of goat meats, were lower in CP 16% and CP 14% groups than the other two groups. Water holding capacity of goats meats from CP 16% was higher than those from CP 18% group(P<0.05). Results from panel test showed that juiciness of meats from CP 16% group was higher than those from CP 12% group(P<0.05). Meats from CP 16% also was tested to be more tender than meats from the other groups. Results from this work suggest that the optimum crude protein level in growing goat's concentrate is 14-16% and that increase above this level seems not to improve meat production.