• Journal of the Korean Institute of Gas
• /
• v.23 no.2
• /
• pp.1-8
• /
• 2019

Because of environmental pollution problem, interests in hydrogen energy has been concentrating sharply. Especially in Korea, the market related with fuel cell vehicles and hydrogen refueling stations is increasing actively under the government-led. However, the actual contributions to environmental improvement effect of hydrogen energy is required to be evaluated with representing reality. In this sense, lots of conventional analyzing tools have some limitations to adapt in Korea's situation directly. It is caused by the differences of raw energy market between the US and Korea. That is, most of analytic tools are developed by representing energy market of the US, where can produce variety of raw feed energy sources. Therefore, in this paper, we propose mass balance based numerical analyzing method, which is suitable for the actual hydrogen production process in Korea for exact evaluation of $CO_2$ emission amount in this country. Using proposed method, we has demonstrated reformed hydrogen from natural gas, LPG and naphtha, electrolysis-based hydrogen, and COG-based hydrogen. Furthermore, with the comparison of GREET program analysis results, robustness of numerical analysis method is demonstrated.

• Korean Journal of Environmental Biology
• /
• v.36 no.4
• /
• pp.659-664
• /
• 2018

In this study, two essential oils (EOs) extracted from Aleriana fauriei and Alpinia galangal were formulated as an emulsifiable concentrate (EC) and a granule. In the evaluation of their acute toxicity on fishes, Cyprinus carpio adults were used and the toxicities were determined in a static condition. The formulations were prepared from the essential oil extracted by three different methods namely steam distillation (SD), solvent extraction (SE) and supercritical fluid extraction (SFE). The acute toxicities were calculated using $LC_{50}$ values. Among EOs, only the EO extracted by solvent showed acute toxicities on carps. Some of the EC, EOs of Aleriana fauriei did not exhibit toxicity, while EOs from Alpinia galangal showed potent acute toxicities on carps. Among the granules, granules formulated with Aleriana fauriei EO extracted by SD method and Alpinia galangal EO extracted by SFE method showed acute toxicities on fishes. Nevertheless, $LC_{50}$ of ECs and granules formulated with all types of EOs in this study was higher than the fish toxicity level III for pesticides suggested by Korea Rural Development Administration. Furthermore, cytochrome P450 1A and glutathione S-transferase were confirmed as biomarkers in carps in response to the exposure to Alpinia galangal EO extracted by SD and SFE method, tracking Alpinia galangal EO in the aquatic environment.

• Applied Chemistry for Engineering
• /
• v.21 no.2
• /
• pp.148-153
• /
• 2010

This study was carried out to investigate the effect of extraction methods on the physicochemical characteristics using seed oil of wild green tea (Camellia sinensis). When the solvent extraction method after grinding and steam treatment (SGS) was used for oil extraction, the yield was highest. The specific gravity was a range of $0.91{\sim}0.94g/cm^{3}$ irrespective of extraction methods of oil. However, the light in the solvent extraction method after grinding (SG), the red in the pressure extraction method after grinding and roasting treatment (PGR), and the yellow in SG method were highest. Among various fatty acids, the concentrations of C16 : 0, C18 : 1 and C18 : 2 were highest, irrespective of extraction methods. Especially, the C16 : 0 concentration was in the order of SG (34.78%), SGS (23.04%), and PRGS method (23.01%), the C18 : 1 concentration was in the order of PGR (43.35%), SGS (42.7%), SG method (39.0%), and in the case of C18 : 2, it was in order of PGR (23.15%), SGS (23.03%), and SG method (15.01%). The saturated fatty acid concentration was in the order of SG (40.59%), PGR (31.61%), and SGS method (30.1%). On the other hand, in the case of the unsaturated fatty acid, it was in the order of SGS (69.9%), PGR (68.39%), and SG method (59.41%). The acid values in the SGS and SG method after 10 days of storage were in the range of 6~8 mgKOH/g. However, in the case of PGR method, it was increased with the increase of storage time and was 49.3 mgKOH/g after 60 days. The peroxide values in the SGS and SG method were in the range of 60~100 mEq/g from 10 to 60 days of storage. On the other hand, when the storage time was increased from 10 to 30 days, it was sharply increased from 60 to 240 mEq/g. The rancidity was in the order of $Fe^{2+}$, $Cu^{2+}$, $Cr^{2+}$, $Zn^{2+}$ and $Ni^{2+}$, irrespective of extraction methods. Especially, when butylated hydroxyanisole (BHA) was added into oil containing 1.0 ppm of <$Fe^{2+}$, the peroxide value was decreased from 539.4 to 216.6%. These results show that seed oil of Camellia sinensis grown in Iksan can be applied as sources for cosmetics, detergents, food, and pharmaceuticals.

• Journal of Intelligence and Information Systems
• /
• v.17 no.4
• /
• pp.109-130
• /
• 2011

One of the major problems in the area of data mining is the size of the data, as most data set has huge volume these days. Streams of data are normally accumulated into data storages or databases. Transactions in internet, mobile devices and ubiquitous environment produce streams of data continuously. Some data set are just buried un-used inside huge data storage due to its huge size. Some data set is quickly lost as soon as it is created as it is not saved due to many reasons. How to use this large size data and to use data on stream efficiently are challenging questions in the study of data mining. Stream data is a data set that is accumulated to the data storage from a data source continuously. The size of this data set, in many cases, becomes increasingly large over time. To mine information from this massive data, it takes too many resources such as storage, money and time. These unique characteristics of the stream data make it difficult and expensive to store all the stream data sets accumulated over time. Otherwise, if one uses only recent or partial of data to mine information or pattern, there can be losses of valuable information, which can be useful. To avoid these problems, this study suggests a method efficiently accumulates information or patterns in the form of rule set over time. A rule set is mined from a data set in stream and this rule set is accumulated into a master rule set storage, which is also a model for real-time decision making. One of the main advantages of this method is that it takes much smaller storage space compared to the traditional method, which saves the whole data set. Another advantage of using this method is that the accumulated rule set is used as a prediction model. Prompt response to the request from users is possible anytime as the rule set is ready anytime to be used to make decisions. This makes real-time decision making possible, which is the greatest advantage of this method. Based on theories of ensemble approaches, combination of many different models can produce better prediction model in performance. The consolidated rule set actually covers all the data set while the traditional sampling approach only covers part of the whole data set. This study uses a stock market data that has a heterogeneous data set as the characteristic of data varies over time. The indexes in stock market data can fluctuate in different situations whenever there is an event influencing the stock market index. Therefore the variance of the values in each variable is large compared to that of the homogeneous data set. Prediction with heterogeneous data set is naturally much more difficult, compared to that of homogeneous data set as it is more difficult to predict in unpredictable situation. This study tests two general mining approaches and compare prediction performances of these two suggested methods with the method we suggest in this study. The first approach is inducing a rule set from the recent data set to predict new data set. The seocnd one is inducing a rule set from all the data which have been accumulated from the beginning every time one has to predict new data set. We found neither of these two is as good as the method of accumulated rule set in its performance. Furthermore, the study shows experiments with different prediction models. The first approach is building a prediction model only with more important rule sets and the second approach is the method using all the rule sets by assigning weights on the rules based on their performance. The second approach shows better performance compared to the first one. The experiments also show that the suggested method in this study can be an efficient approach for mining information and pattern with stream data. This method has a limitation of bounding its application to stock market data. More dynamic real-time steam data set is desirable for the application of this method. There is also another problem in this study. When the number of rules is increasing over time, it has to manage special rules such as redundant rules or conflicting rules efficiently.

• Food Science and Preservation
• /
• v.20 no.6
• /
• pp.827-833
• /
• 2013

In this study we investigated physicochemical properties of Zanthoxylum schinifolium seeds oil base extracts. Supercritical fluid extraction (SFE), roast pressure (RPM) and steam pressure (SPM) method were used for oil base extracts. The pressure and temperature conditions of SFE method were $70{\sim}80kgf/cm^2$ and below $30^{\circ}C$, respectively, by newly designed SFE-$CO_2$ system. The yield of extraction was 38.5% at the SFE method and others were 30% in each. Refractive index of oil base extracts, there was also no difference between them as 1.470~1.473. At the SFE method, viscosity observed higher value better than two method that showed as 181.88~209.93 according to the extraction time. Three oil base extracts showed difference in color which was low in b value at SFE, especially. The result of acid value at RPM that was lower as 0.93 mg/g than 2.36~2.64 mg/g of SFE method. Saponification value ranged $182.96{\sim}196.57mg{\cdot}KOH/g$ in three extraction method. At SPM, TBA value showed as 158.96 mg/kg, but in the SFE method ranged higher value as 201.30~347.14 mg/kg. Fatty acids analysed with 18 varieties in all oil base extracts and the composition of saturated/unsaturated fatty acids was 17:83(v/v) at SEF. Especially, ${\omega}$-3,6,9 fatty acids observed at SFE and SPM, but did not appeared at RPM. Fatty acid of ${\omega}$-6,9 detected in all cases.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.2
• /
• pp.947-953
• /
• 2012

In this study we investigated the manufacturing method for the activated carbon using the char from the pyrolysis of waste tire. The physical activation method using the steam in the fixed-bed quartz reactor was used for preparation of activated carbon. The primary experiment parameters are the activation temperature, activation time, heating rate, and the injection quantity of active agent. From the results of pore distribution of activated carbon, the micropore which was made in $850^{\circ}C$ of activation temperature, $5^{\circ}C$/min of heating rate, and 3 hours of activation time was developed in biggest quantity, and mesopore and macropore were developed in the biggest quantity too. The optimum conditions for producing the activated carbon using the pyrolysis residue were $850^{\circ}C$ of activation temperature, 3 hours of activation time, $5^{\circ}C$/min of heating rate, and 3 g $H_2O/char-g{\cdot}hr$ of active agent through this study. The produced activated carbon in these conditions showed that the potentiality of utilization as activated carbon because the BET specific surface area was $517.6m^2/g$ and total pore volume was $0.648cm^3/g$.

• The Korean Journal of Food And Nutrition
• /
• v.17 no.2
• /
• pp.206-211
• /
• 2004

It is very important to minimize the acid value of oil in the oil and fat industry, because acid value of oil products are a indicator quality. This study was performed to investigate change of moisture content, acid value and free fatty acid content by drying condition such as drying method, temperature and drying time on steamed duck egg york. Also, change of fatty acid composition by acid value. The acid values, moisture contents and free fatty acid contents were showed comparatively lower value by spray drying and freeze drying than by steam drying. but difference that keep in mind between each drying method was not looked. Whereas moisture content, acid value and free fatty acid content of effect of drying temperature reaches in lowest value. also, did not show change until dry 12hours reaching to lowest value by 3.1, 3.0％ and 0.98％ after dry 9hours both moisture content, acid value and free fatty acid content. Also, acid value increase, free fatty acid was increased, where unsaturated fatty acid showed that decrease rapidly.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.26 no.12A
• /
• pp.2109-2119
• /
• 2001

In this paper, a fast information extraction algorithm for object-based MPEG-4 application from MPEG-2 bit-steam is proposed. For object-based MPEG-4 conversion, we need to extract such information as object-image, shape-image, macro-block motion vector, and header information from MPEG-2 bit-stream. If we use the extracted information, fast conversion for object-based MPEG-4 is possible. The proposed object extraction algorithm has two important steps, namely the motion vectors extraction from MPEG-2 bit-stream and the watershed algorithm. The algorithm extracts objects using user\`s assistance in the intra frame and tracks then in the following inter frames. If we have an unsatisfactory result for a fast moving object, the user can intervene to correct the segmentation. The proposed algorithm consist of two steps, which are intra frame object extracts processing and inter frame tracking processing. Object extracting process is the step in which user extracts a semantic object directly by using the block classification and watersheds. Object tacking process is the step of the following the object in the subsequent frames. It is based on the boundary fitting method using motion vector, object-mask, and modified watersheds. Experimental results show that the proposed method can achieve a fast conversion from the MPEG-2 bit-stream to the object-based MPEG-4 input.

• Journal of the Korean Chemical Society
• /
• v.38 no.5
• /
• pp.351-358
• /
• 1994

The spectrophotometric determination of trace selenium(Ⅳ) using its catalytic reaction has been studied in aqueous solutions. The catalytic reaction of phenylhydrazine hydrochloride with selenium(Ⅳ) in an acidic aqueous medium produces benzenediazonium ion which will be converted into a red-coloured azo dye by coupling with H-acid(8-amino-1-naphtol-3,6-disulfonic acid disodium salt). For the reaction, the experimental conditions such as amounts of the reagents and pH of the sample solutions were optimized. After 15 ml of the sample solution was treated with 1 ml of 0.1 M EDTA solution to mask $Fe^{3+}$, etc., 1 ml of 0.06 M phenylhydrazine hydrochloride, 1 ml of 0.02 M H-acid, and 3 ml of 0.3 M-$KClO_3$ were added into the solution, sequentially. The solution was adjusted to pH 1.4 with HCl. After it was heated in a steam bath for 30 minutes, the solution was cooled down to a room temperature and then diluted to 25 ml with deionized distilled water. A blank solution for the absorbance measurement was prepared from the deionized water. The absorbance was measured at 527 nm. Using the above procedure, the trace amount of selenium was determined in natural waters such as tap, river and pond waters by a standard curve method and recoveries of Se spiked to samples were also obtained. From the recoveries of 104 to 111%, it could be concluded that this method was applicable to the quantitative determination of ng/ml level of selenium in natural waters.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.32 no.4
• /
• pp.410-417
• /
• 2012

Currently domestic thermal and nuclear power plants are comprised of many type's condenser and steam generator tubes to produce the electricity of good quality. There are some methods to inspect these tubes in the event that several defects were discovered in these facilities. Among many non-destructive methods, we used guided wave to inspect the soundness of tubes, because this method is very fast to detect the defect and very simple to install the equipment and also, can inspect up to the long range at a fixed point. Also, this method has a drawback that does not detect a very small size defect. So, we made an effort to overcome this drawback through the experimentation and signal analysis according to the size and shape of the defect through the manufacture of various artificial cracks capable to generate within the small size tube in the study and we anticipate that these detect limits can be overcome along with the development of the signal processing and manufacturing technology of the sensor for the inspection.