• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
• /
• 2003.04a
• /
• pp.363-368
• /
• 2003

We have successfully developed a more effective algorithm to extract the lineament in the area covered by wide alluvial deposits characterized by a relatively narrow range of brightness in the Landsat TM image, while the currently used algorithm is limited to the mountainous areas. In the new algorithm, flat areas mainly consisting of alluvial deposits were selected using the Local Enhancement from the Digital Elevation Model (DEM). The aspect values were obtained by 3${\times}$3 moving windowing of Zevenbergen & Thorno's Method, and then the slopes of the study area were determined using the aspect values. After the lineament factors in the alluvial deposits were revealed by comparing the threshold values, the first rank lineament under the alluvial deposits were extracted using the Hough transform In order to extract the final lineament, the lowest points under the alluvial deposits in a given topographic section perpendicular to the first rank lineament were determined through the spline interpolation, and then the final lineament were chosen through Hough transform using the lowest points. The algorithm developed in this study enables us to observe a clearer lineament in the areas covered by much larger alluvial deposits compared with the results extracted using the conventional existing algorithm. There exists, however, some differences between the first rank lineament, obtained using the aspect and the slope, and the final lineament. This study shows that the new algorithm more effectively extracts the lineament in the area covered with wide alluvlal deposits than in the areas of converging slope, areas with narrow alluvial deposits or valleys.

• Journal of fish pathology
• /
• v.18 no.1
• /
• pp.19-28
• /
• 2005

Scuticociliatosis has badly settled one of most damaging diseases during the seedling production process of olive flounder. Paralichthys olivaceus in Korea. We isolated a new type of Scuticociliate from flounder. The parasite metamorphoses to ciliate and cyst phases with each other by environmental changes and survive for a relatively long span. The ciliate was measured average 41.8 ${\mu}m$ in length and 21.0 ${\mu}m$ in width, and cyst was 17.0 ${\mu}m$ and 13.5 ${\mu}m$, respectively. Nutritional condition was determined as a major parameter of metamorphosing between ciliate and cyst stages. The ciliate transforms to a cyst stage because of food shortage, and the cyst returns to a ciliate stage with a favorite environmental condition and shows active growth and reproduction. The ciliate multiplied at the maximal density of $2.9 {\times} 10^5 {m\ell}^{-1}$cells in vitro cultivation at $15 ^{\circ}C$temperature using MS BHI medium and bacterial food sources. The ciliate could be proliferated at a 2.5 to $30 ^ \circ}C$ temperature range, pH 6 to 9, and 1 to 55 ppt salinity. Particularly, it survived over one week at $0 ^{\circ}C$temperature showing a high resistance against unfavorable environmental conditions. And the cyst survived for 320 days in the condition of $5 ^{\circ}C$with no feeding, but its survival period was markedly shortened in higher temperature conditions. The chemotherapeutants (formalin and hydrogen peroxide) were clarified as effective chemicals against the ciliate during in vitro trials, but the effect of therapeutants differed in proportion, depending upon the density and the bathing time of chemical compounds.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.16 no.4
• /
• pp.34-43
• /
• 2012

The behaviors of the curved bridges which has been constructed in the RAMP or Interchange are very complicate and different than orthogonal bridges according to the variations of radius of curvature, skew angle and spacing of shoes. Occasionally, the camber of girder and negative reactions can be occurred due to bending and torsional moment. In this study, the effects on the negative reaction in the curved bridge were investigated on the basis of design variables such as radius of curvature, skew angle, and spacing of shoes. For this study, the twin-steel box girder curved bridge with single span which is applicable for the RAMP bridges with span length(L) of 50.0m and width of 9.0m was chosen and the structural analysis to calculate the reactions was conducted using 3-dimensional equivalent grillage system. The value of negative reaction in curved bridges depends on the plan structures of bridges, the formations of structural systems, and the boundary conditions of bearing, so, radius of curvature, skew angle, and spacing of shoes among of design variables were chosen as the parameter and the load combination according to the design standard were considered. According to the results of numerical analysis, the negative reaction in curved bridge increased with an decrease of radius of curvature, skew angle, and spacing of shoes, respectively. Also, in case of skew angle of $60^{\circ}$ the negative reaction has been always occurred without regard to ${\theta}/B$, and in case of skew angle of $75^{\circ}$ the negative reaction hasn't been occurred in ${\theta}/B$ below 0.27 with the radius of curvature of 180m and in ${\theta}/B$ below 0.32 with the radius of curvature of 250m, and in case of skew angle of $90^{\circ}$ the negative reaction hasn't been occurred in the radius of curvature over 180m and in ${\theta}/B$ below 0.38 with the radius of curvature of 130m, The results from this study indicated that occurrence of negative reaction was related to design variables such as radius of curvature, skew angle, and spacing of shoes, and the problems with the stability including negative reaction will be expected to be solved as taken into consideration of the proper combinations of design variables in design of curved bridge.

• Korean Journal of Ecology and Environment
• /
• v.42 no.2
• /
• pp.260-269
• /
• 2009

Hwabuk Dam has been under construction to reduce flood damage in Nakdong River watershed and to supply stable water for middle area of Gyeongbuk Province. Therefore, fish investigation in up and downstream of the dam was conducted from 2004 to 2008 in order to determine any negative effect on fish community due to dam construction and to use as fundamental data for conserving species diversity and maintaining stream health. According to data analysis on water quality, temperature, dissolved oxygen, pH, suspended solids, and total E-coli had seasonal variation, but they did not significantly differ in sites. However, biological and chemical oxygen demand, chlorophyll-a, nitrogen, and phosphorus representing organic matter and nutrient concentration were higher in upper site and decreased to lower site so that they differed by site. Concentration of arsenic among the heavy metals was less than 0.05 mg $L^{-1}$, which is regulated for protection of human health in water quality standard, except for 0.092 mg $L^{-1}$ in June 2005. During the study period, the total number of fish caught from the 6 sites was 10,263 representing 7 families 19 species. Among them, dominant and subdominant species were Korean chub (Zacco koreanus, 62.5%) and Chinese minnow (Rhynchocypris oxycephalus, 10.6%) which inhabit mostly in mid and upper streams, Korea. Among the 19 species, Korean endemic species were 9 species (47.4%) including Korean slender gudgeon (Squalidus gracilis majimae), Korean dark sleeper (Odontobutis platycephala), and Korean shiner (Coreoleuciscus splendidus). There was several individuals of the $1^{st}$-class endangered species, Naktong nose loach (Koreocobitis nahtongensis), caught in 2005${\sim}$2007, and no introduced species of fish was found in entire sampling period. According to result of community analysis, dominance index decreased toward lower site, but diversity and richness indices increased toward lower site. The equation of length-weight relationship on the dominant species was TW=0.000003$(TL)^{3.2603}$. The parameter b in the equation was greater than 3.0 indicating good nutritional condition in the populations. Compared to populations of Korean chub in other streams, the population in Hwabuk Dam watershed had higher mean of condition factor by size indicating better growth rate. With fish fauna and multi-metric health assessment model in each sampling attempt, index of biotic integrity (IBI) was evaluated and it resulted mostly in good (26${\sim}$35) and excellent (36${\sim}$40) condition in all sites, and the mean of IBI was the highest in site 5. The results indicate that it is very important to study not only environmental impact assessment with fish composition but also stream health assessment in order to conserve healthy aquatic ecosystem.

• Journal of Korean Society of Disaster and Security
• /
• v.12 no.2
• /
• pp.73-82
• /
• 2019

Recently, as the occurrence frequency of sudden floods due to climate change increased, the flood damage on riverside social infrastructures was extended so that there has been a threat of overflow. Therefore, a rapid prediction of potential flooding in riverside social infrastructure is necessary for administrators. However, most current flood forecasting models including hydraulic model have limitations which are the high accuracy of numerical results but longer simulation time. To alleviate such limitation, data driven models using artificial neural network have been widely used. However, there is a limitation that the existing models can not consider the time-series parameters. In this study the water surface elevation of the Hangang River bridge was predicted using the NARX model considering the time-series parameter. And the results of the ANN and RNN models are compared with the NARX model to determine the suitability of NARX model. Using the 10-year hydrological data from 2009 to 2018, 70% of the hydrological data were used for learning and 15% was used for testing and evaluation respectively. As a result of predicting the water surface elevation after 3 hours from the Hangang River bridge in 2018, the ANN, RNN and NARX models for RMSE were 0.20 m, 0.11 m, and 0.09 m, respectively, and 0.12 m, 0.06 m, and 0.05 m for MAE, and 1.56 m, 0.55 m and 0.10 m for peak errors respectively. By analyzing the error of the prediction results considering the time-series parameters, the NARX model is most suitable for predicting water surface elevation. This is because the NARX model can learn the trend of the time series data and also can derive the accurate prediction value even in the high water surface elevation prediction by using the hyperbolic tangent and Rectified Linear Unit function as an activation function. However, the NARX model has a limit to generate a vanishing gradient as the sequence length becomes longer. In the future, the accuracy of the water surface elevation prediction will be examined by using the LSTM model.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.66 no.2
• /
• pp.171-181
• /
• 2021

The purposes of this study were to determine how changes in temperature affect germination rates and growth of hulled and dehulled barley, malting barley, and naked oat plants, and to measure chlorophyll content, photosynthetic efficiency, and secondary compounds (total phenol, total flavonoid, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity) in plants grown at 13℃ or 25℃). Various types of barley seeds were collected from areas with ideal conditions for barley cultivation, hereinafter referred to as IA, and also from areas where barley cultivation is more difficult due to lower temperatures, hereinafter referred to as LTA. Seeds were tested for seed vigor. While there were significant differences in the electrical conductivity values between seeds collected from certain specific areas, no significant differences were evident between IA and LTA seeds, regardless of the type of barley seed. When plants were grown at 25℃, there were no significant differences in germination rates, plant height, root length and shoot fresh weight between plants originating from IA and LTA. However, there were differences in the measured parameters of some specific seeds. Similarly, under the low temperature condition of 13℃, no differences in the emergence rate, plant height, and shoot fresh weight were evident between plants originating from IA or LTA, regardless of the type of barley. However, there were differences between some specific seeds. One parameter that did vary significantly was the emergence date. Hulled barley and malting barley emerged 5 days after sowing, whereas naked oats emerged 7 days after sowing. There were no differences in the chlorophyll content and photosynthetic efficacy, regardless of the type of barley. There were no significant differences in total phenol, total flavonoid content, and DPPH radical scavenging activity between plants originating from IA and LTA, regardless of the type of barley. However, there were differences between some specific seeds. In particular, for malting barley the total flavonoid content differed in the order of Gangjin > Changwon > Haenam = Jeonju > Naju. The results indicate that crop growth, yield and content of secondary compounds in various types of barley may be affected by climate change.

• Journal of the Korea Society of Computer and Information
• /
• v.14 no.12
• /
• pp.157-167
• /
• 2009

Recently, the leakage of confidential information and personal information is taking place on the Internet more frequently than ever before. Most of such online security incidents are caused by attacks on vulnerabilities in web applications developed carelessly. It is impossible to detect an attack on a web application with existing firewalls and intrusion detection systems. Besides, the signature-based detection has a limited capability in detecting new threats. Therefore, many researches concerning the method to detect attacks on web applications are employing anomaly-based detection methods that use the web traffic analysis. Much research about anomaly-based detection through the normal web traffic analysis focus on three problems - the method to accurately analyze given web traffic, system performance needed for inspecting application payload of the packet required to detect attack on application layer and the maintenance and costs of lots of network security devices newly installed. The UTM(Unified Threat Management) system, a suggested solution for the problem, had a goal of resolving all of security problems at a time, but is not being widely used due to its low efficiency and high costs. Besides, the web filter that performs one of the functions of the UTM system, can not adequately detect a variety of recent sophisticated attacks on web applications. In order to resolve such problems, studies are being carried out on the web application firewall to introduce a new network security system. As such studies focus on speeding up packet processing by depending on high-priced hardware, the costs to deploy a web application firewall are rising. In addition, the current anomaly-based detection technologies that do not take into account the characteristics of the web application is causing lots of false positives and false negatives. In order to reduce false positives and false negatives, this study suggested a realtime anomaly detection method based on the analysis of the length of parameter value contained in the web client's request. In addition, it designed and suggested a WAF(Web Application Firewall) that can be applied to a low-priced system or legacy system to process application data without the help of an exclusive hardware. Furthermore, it suggested a method to resolve sluggish performance attributed to copying packets into application area for application data processing, Consequently, this study provide to deploy an effective web application firewall at a low cost at the moment when the deployment of an additional security system was considered burdened due to lots of network security systems currently used.

• Korean Journal of Poultry Science
• /
• v.33 no.3
• /
• pp.171-179
• /
• 2006

Changes in the chicken testis from hatching to adulthood were studied in Korean native chickens of 1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 21, 24, 28, 32, 44, 52 and 64 weeks (n=13 chickens per group) of age. The present study was to investigate in more detail the post-hatching development of testis in Korean native chickens. Testes of chickens were fixed by whole body perfusion using a fixative containing 2.5% glutaraldehyde in cacodylate buffer, processed and embedded in Epon-araldite. Using $1{\mu}m$ sections stained with methylene blue-azure II, qualitative and quantitative(stereological) morphological studies were performed. Sperm production was measured by routine technique. The average volume of a testis of 1 week old Korean native chickens was determined as 0.015 g and the parameter increased linearly from 1 week to 21 weeks days (28.9 g), and did not change from 21 weeks to 64 weeks. The volume density of the seminiferous tubules increased with age from 32.6% at week 1 to 92.89% at week 64. The volume density of the interstitium represents 67.4% of the testicular parenchyma at week 1. This proportion progressively diminished during development to reach a value of 7.11% at week 64. Total sperm production per testis increased significantly from 18 weeks to 28 weeks and remained unchanged. Sperm production per 1 g testis increased significantly from 18 weeks to 28 weeks, did not change significantly from 28 weeks to 52 weeks, and declined significantly at 64 weeks of age. The average diameter of the seminiferous tubules gradually increased with age from 1 week $(42.4{\mu}m)$ to 21 weeks $(412.8{\mu}m)$. The length of the seminiferous tubules was 0.34 m at 1 week, increased significantly in subsequent age groups and reached 72.2 m by weeks 64. The stage of germ cell development in seminiferous tubules was classified as 1) spermatogonia $(1\sim8\;weeks)$, 2) spermatogonia and spermatocytes $(10\sim12\;weeks)$, 3) spermatogonia, spermatocytes and round spermatids $(14\sim16\;weeks)$, and 4) speramatogonia, spermatocytes, spermatids and spermatozoa $(18\sim64\;weeks)$. These results clarified the pattern of changes in the testicular development in Korean native chickens from hatching to adulthood as 1) neonatal-prepubertal $(1\sim12\;weeks)$, 2) puberty$(14\sim18\;weeks)$, and adult$(21\sim64\;weeks)$.