• Journal of Korea Water Resources Association
• /
• v.35 no.2
• /
• pp.213-220
• /
• 2002

This reserch was focused upon experimental study for wastewater reuse and conducted to evaluate optimum operating conditions of rapid filtration process such as filter flow rate, filtration time and backwashing condition for reuse of secondary-treated effluent using the pilot plant installed in real wastewater treatment plant. Also, the experiment on treatment char-acteristics of coagulant-added activated sludge process was performed to compare with activated sludge succeeded to rapid filtration. As the filtration velocity was 100m/day, the filtration time of the rapid filter connected with activated sludge system was revealed to 40 hours. Backwashing of filter was conducted by water wash and air scour. The optimum backwashing time and backwash flow rate were 10min and 10LPM, respectively. The quantity of backwashing water of the rapid filter was about 2% of total treated water.

• Korean Journal of Food Science and Technology
• /
• v.28 no.6
• /
• pp.1045-1051
• /
• 1996

The influence of electrolyzed acid-water (oxidation-reduction potential (ORP): above 1,150 mV, pH : 2.5) on the survival of some microorganisms was investigated. It was observed that the ORP of electrolyzed acid-water was kept at the level of above 1,000 mV for 15 days at room temperature. Escherichia coli. Salmonella typhi, Staphylococcus aureus and Saccharomyces cerevisiae were not detected after 10 to 40 min in electrolyzed acid-water. However, Bacillus cereus showed higher tolerance to electrolyzed acid-water than other test microorganisms. After 60 min of inoculation, only 0.4% of initial population remained. The investigation of surface sterilization effect on some vegetables was carried out too. Total count of cabbage, Chinese cabbage and kale were reduced to below 3% of initial count, and no coliform was detected after 20 to 60 min of immersion in 5 volumes of electrolyzed acid-water. In the lettuce, total and coliform counts were reduced to 90% and 2% of initial population. This study shows that the electrolyzed acid-water has a potential for the sterilization of food products such as vegetables and fruits which cannot be thermally sterilized.

• KIPS Transactions on Computer and Communication Systems
• /
• v.12 no.10
• /
• pp.299-308
• /
• 2023

As the spectrum shortage problem has accelerated by the emergence of various services, New Radio-Unlicensed (NR-U) has appeared, allowing users who communicated in licensed bands to communicate in unlicensed bands. However, NR-U network users reduce the performance of Wi-Fi network users who communicate in the same unlicensed band. In this paper, we aim to simultaneously maximize the fairness and throughput of the unlicensed band, where the NR-U network users and the WiFi network users coexist. First, we propose an optimal power allocation scheme based on Monte Carlo Policy Gradient of reinforcement learning to maximize the sum of rates of NR-U networks utilizing rate-splitting multiple access in unlicensed bands. Then, we propose a channel occupancy time division algorithm based on sequential Raiffa bargaining solution of game theory that can simultaneously maximize system throughput and fairness for the coexistence of NR-U and WiFi networks in the same unlicensed band. Simulation results show that the rate splitting multiple access shows better performance than the conventional multiple access technology by comparing the sum-rate when the result value is finally converged under the same transmission power. In addition, we compare the data transfer amount and fairness of NR-U network users, WiFi network users, and total system, and prove that the channel occupancy time division algorithm based on sequential Raiffa bargaining solution of this paper satisfies throughput and fairness at the same time than other algorithms.

• Journal of the Institute of Convergence Signal Processing
• /
• v.11 no.3
• /
• pp.215-220
• /
• 2010

In this paper, we propose a new texture-based page segmentation and classification method in which table region, background region, image region and text region in a given document image are automatically identified. The proposed method for document images consists of two stages, document segmentation and contents classification. In the first stage, we segment the document image, and then, we classify contents of document in the second stage. The proposed classification method is based on a texture analysis. Each contents in the document are considered as regions with different textures. Thus the problem of classification contents of document can be posed as a texture segmentation and analysis problem. Two-dimensional Gabor filters are used to extract texture features for each of these regions. Our method does not assume any a priori knowledge about content or language of the document. As we can see experiment results, our method gives good performance in document segmentation and contents classification. The proposed system is expected to apply such as multimedia data searching, real-time image processing.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.23 no.5
• /
• pp.731-735
• /
• 1994

The aims of this study are conducted to investigate the effect of pretreatment with Achatina fucica extract (AFE) in streptozotocin (STZ)-induced diabetic rats. Serum glucose, total lipid and triglyceride levels of administration group of AE in diabetic rats induced by STZ were significant high levels than that of control group. However, glucose, triglyceride and lipid levels were significant lower level in group of pretreatment with AFE and Atheroslerotic index decreased in the group of treatment of AFE when those levels compared with that of STZ-treated group. Serum lipase activity was inhibited in the control group STZ induced diabetic rats, in contrast lipase activity increased in the group of AFE administration. These results suggested that AFE may use to prevent the diabetes mellitus induced by STZ.

• Spatial Information Research
• /
• v.19 no.2
• /
• pp.47-56
• /
• 2011

Typical tree-based spatial index structures are divided into a data-partitioning index structure such as R-Tree and a space-partitioning index structure such as KD-Tree. In recent years, researches on hybrid index structures combining advantages of these index structures have been performed extensively. However, because the split boundary extension of the node to which a new spatial object is inserted may extend split boundaries of other neighbor nodes in existing researches, overlaps between nodes are increased and the query processing cost is raised. In this paper, we propose a hybrid index structure, called SQR-Tree that can support efficient processing of spatial queries to solve these problems. SQR-Tree is a combination of SQ-Tree(Spatial Quad- Tree) which is an extended Quad-Tree to process non-size spatial objects and R-Tree which actually stores spatial objects associated with each leaf node of SQ-Tree. Because each SQR-Tree node has an MBR containing sub-nodes, the split boundary of a node will be extended independently and overlaps between nodes can be reduced. In addition, a spatial object is inserted into R-Tree in each split data space and SQ-Tree is used to identify each split data space. Since only R-Trees of SQR-Tree in the query area are accessed to process a spatial query, query processing cost can be reduced. Finally, we proved superiority of SQR-Tree through experiments.

• The Korean Journal of Mycology
• /
• v.11 no.4
• /
• pp.163-167
• /
• 1983

Oyster mushroom, Pleurotus ostreatus, was exposed to 0.625, 1.25, 2.5 and 5.0 ppm $SO_2$ for 15, 30, 60, 120 and 180 minutes at the tiny button stage in order to study the effect of sulfur dioxide on growth and cap discoloration of the mushroom. The cap color was changed from grey to greyish blue at low dosage of sulfur dioxide, and with the lapse of exposing time and rasing sulfur dioxide concentration up, the color was changed to light brown and dark brown. The cap dicoloration was begun by the exposure of sulfur dioxide to 0.625 ppm for 120 minutes, to 1.25 ppm for 30 minutes and to 2.5 ppm for 15 minutes. By the exposure of sulfur dioxide to 1.25 ppm for 120 minutes, to 2.5 ppm for 30 minutes, its growth was inhibited, but the fruit body was died by the exposure of the gas to 2.5 ppm for 180 minutes and to 5.0 ppm for 60 minutes. Sulfur dioxide inhibited conspicuously the development of basidia and basidiospores of the mushroom and 20 to 25 percent of basidiospores formed were abnormal. Ethylene production by mushroom exposed to sulfur dioxide was not recognized.

• Journal of KIISE:Databases
• /
• v.28 no.3
• /
• pp.315-323
• /
• 2001

The concept of vertical partitioning has been discussed so far in an objective of improving the performance of query execution and system throughput. It can be applied to the areas where the match between data and queries affects performance, which includes partitioning of individual files in centralized environments, data distribution in distributed databases, dividing data among different levels of memory hierarchies, and so on. In general, a vertical partitioning algorithm should support n-ary partitioning as well as a globally optimal solution for the generation of all meaningful fragments. Most previous methods, however, have some limitations to support both of them efficiently. Because the vertical partitioning problem basically includes the fuzziness property, the proper management is required for the fuzziness problem. In this paper we propose an efficient vertical $\alpha$-partitioning algorithm which is based on the fuzzy theory. The method can not only generate all meaningful fragments but also support n-ary partitioning without any complex mathematical computations.

• Korean Journal of Microbiology
• /
• v.49 no.2
• /
• pp.191-194
• /
• 2013

The fresh fruit bodies of Pleurotus eryngii var. ferulae was irradiated with ultraviolet (UV)-B (280-320 nm) in order to increase vitamin $D_2$ contents, which was assayed using HPLC (Waters 1525, USA). The vitamin $D_2$ contents were $3.5{\mu}g/g$ after 3 min UV-B irradiation ($21.6KJ/m^2$) and $6.02{\mu}g/g$ after 5 min UV-B irradiation ($36KJ/m^2$), respectively, which showed the significant increase considering the vitamin $D_2$ content ($0.01{\mu}g/g$) before UV-B irradiation. This increasing effect was confirmed also for other edible mushrooms; Pleurotus eryngii, from $0.09{\mu}g/g$ to $2.75{\mu}g/g$ (3 min) and $5.21{\mu}g/g$ (5 min); Lentinus edodes, from $0.021{\mu}g/g$ to $3.02{\mu}g/g$ (3 min) and $3.78{\mu}g/g$ (5 min); Pleurotus ostreatus, from $0.19{\mu}g/g$ to $9.63{\mu}g/g$ (3 min) and $11.6{\mu}g/g$ (5 min). Although the original content of vitamin $D_2$ was the highest in P. ostreatus, the extent of increase by UV irradiation was remarkably high in P. eryngii var. ferulae.

• Proceedings of the Korean Information Science Society Conference
• /
• 2004.04b
• /
• pp.823-825
• /
• 2004

본 연구에서는 필기체 한글의 글자단위의 분할을 위해 배경 세선화(Background thinning)라는 방법을 제안한다. 배경 세선화 방법은 글자와 글자 사이에 존재하는 배경의 정보를 세선화 처리하여 필기체 한글에서 많이 발생할 수 있는 중첩(Overlap)글자와 연결(Touched)글자를 서로 분할하는데 효과적인 성능을 보였다. 배경 세선화를 이용하여 글자를 분할하는 방법은 인식과정의 판단을 필요하지 않은 외적분할 방법으로 빠른 속도의 분할 성능을 보였다. 이 방법은 특히, 중첩된 글자의 분할에 탁월한 성능을 보였을 뿐만 아니라, 연결된 글자에 대해서도 좋은 성능을 보였다.