• Journal of KIISE:Computing Practices and Letters
• /
• v.5 no.4
• /
• pp.457-466
• /
• 1999

원자력 발전소 계측 제어 시스템, 의료 관련 시스템, 항공 관련 시스템 등 실생활과 밀접한 시스템에 소프트웨어의 사용이 점차 증가하고 있다. 이러한 시스템에서 소프트웨어의 오류는 예기치 않는 사고를 유발하여 인명, 재산상의 심각한 타격을 줄 수 있다. 그러므로 고신뢰도 소프트웨어의 개발 시에는 반드시 시스템의 안전성을 보장해 주어야 한다. 역방향 안전성 분석 방법은 시스템의 안전성을 분석하는 한가지 방법으로서 시스템의 위험 상태를 정의하고 그 위험의 원인들을 추적, 분석함으로써 안전성에 대한 효율적인 분석을 수행할 수 있는 장점을 갖는다. 이 논문에서는 소프트웨어 개발 초기 단계에서 안전성을 분석할 수 있는 방법으로 Colored Petri Nets(CPN)에 기반을 둔 역방향 안전성 분석 방법을 제시한다. 또한 CPN 역방향 안전성 분석 도구인 SAC(Safety Analyzer for CPN)의 설계 및 구현에 대해 언급한다. SAC은 기존의 상용 CPN 모델링 도구인 Design/CPN과 연계하여 사용될 수 있으므로 CPN으로 모델링된 시스템의 안전성을 분석할 수 있다는 장점이 있다. 이 논문에서는 예제로 자동 교통 제어 시스템의 일부를 CPN으로 모델링하고 SAC을 이용한 분석 과정을 기술한다.Abstract In safety-critical systems such as nuclear power plants, medical machines, and avionic systems which are closely related with our livings, the usage of software in the controlling part is growing rapidly. Since software errors in safety-critical systems may cause serious accidents leading to financial or human damages, system safety should be ensured during and after development of a system. A backward safety analysis technique defines system hazards and tries to trace their causes by analyzing system states backward. In this paper, we provide a backward safety analysis technique based on Colored Petri Nets(CPN), which is applicable to the early software development phase. Also Safety Analyzer for CPN(SAC), the supporting tool, is designed and implemented. Since SAC is compatible with Design/CPN, a commercial tool for supporting CPN, it can be applicable to analyze safety in practical problems. As an example, we model a part of the traffic light control system using CPN and analyze safety properties of the model using the SAC tool.

• Economic and Environmental Geology
• /
• v.48 no.6
• /
• pp.537-543
• /
• 2015

In Korea, the use of world geodetic system(WGS) has been mandated in year 2010. Accordingly, the national geographic information institute(NGIS) provides the digital maps according to the WGS. Nevertheless, most of the digital geological maps are still based on the Tokyo Datum(TD). Therefore, users should conduct 2D/3D geological spatial analysis after converting the coordinates of digital geological maps to WGS. The conversion process is often tedious and troublesome for certain users. Therefore, in this study, the method to transform coordinate from TD to WGS using ArcToolbox is introduced for users not familiar with the process. For a better appreciation, the Chungju and Hwanggang-ri digital sheets of 1:50,000 scale was chosen as an example. Here, Chungju and Hwanggang-ri sheets were defined based on the TD-central origin and TD-east origin, respectively. The two sheets were merged after the transformation of TD-east origin of Hwanggang-ri to the TD-central origin, and eventually transformed to WGS-central origin. The merged map was found to match exactly with the digital map(Daeso 367041). The problem of coordinate determination in previous digital geological maps was solved effectively. The proposed method is believed to be helpful to 2D/3D geological spatial analysis of various geological thematic maps.

• Analytical Science and Technology
• /
• v.27 no.5
• /
• pp.261-268
• /
• 2014

In advanced countries, a variety of consumer exposure assessment models including CONSEXPO, are developed to manage risks of consumer products containing hazardous materials. The models are used to assess the risks of exposure to hazardous chemicals in consumer products, which serves as a foundation for regulation standards. In this study, exposure assessment models applicable for various scenarios were reviewed and a proper model was applied for the selected products and risk assessment was conducted at each stage to establish a risk assessment procedure for different types of products. Based on the exposure scenario, exposure factor was selected and according to the algorithm produced based on CONSEXPO exposure model, some level of phthalates were detected from some types of PVC flooring. However, a correlation between phthalate content and migration rate showed r-square 0.0065, little correlation, which is inadequate for estimating standard value. For this reason, it seems valid that the current standard be in place. Additionally, any new standard was not suggested as VOCs were not found harmful to human health, allowing the existing standard to be continuously applied. No migration rate was found for heavy metals and risk assessment was not performed accordingly. In this aspect, it is presumed that hazards to health through dermal exposure would be very little.

• Analytical Science and Technology
• /
• v.29 no.6
• /
• pp.283-292
• /
• 2016

Conventional fingerprint powders used during crime scene investigations pose potential health hazards. Thus, multiple natural replacement powders, including squid ink powder, indigo and rice powder were used to develop (visualize) latent fingerprints on non-porous surfaces (e.g., glass, plastic and tile). Fingerprints developed using the natural powders were compared using the Automatic Fingerprint Identification System (AFIS) with those developed with traditional black powder. The peak areas of ridges were also compared using densitometric image analyses. Collectively, objective and quantitative evaluation methods were developed. The effectiveness of natural powders varied depending on the surface but, in general, squid ink powder performed well on most surfaces. Indigo powder performed well on tile surfaces, while rice powder performed well on glass surfaces. Plastic was the most difficult surface from which to develop fingerprints. Image analysis using Field Emission Scanning Electron Microscopy (SEM) demonstrated the importance of the size and shape of natural powder particles to properly adhere to the ridges. Although densitometric image analyses did not correlate the number of minutiae and ridge peak areas, an unbiased, objective evaluation method would be possible using image analyses with a reference image. Additional experimentation will yield safe and cost-effective natural powders with which adequate fingerprint development can be performed.

• The Journal of Engineering Geology
• /
• v.26 no.2
• /
• pp.207-221
• /
• 2016

As greater numbers of fill dams and reservoirs become old, the risks of damage or embankment collapse increases. However, few studies have considered the deterioration and hazard classification of the internal core layers of fill dams. This study reports the results of geotechnical investigations of 13 earth-cored fill dams in Korea, based on no-water borehole drilling, Standard Penetration Test, and 2D and 3D electrical resistivity surveys along with in situ and laboratory testing. High-capacity no-water boring minimized core layer disturbance while providing continuous core sample recovery. The results allow the classification of potential hazards related to the existing core layers based on both visual inspection of the recovered samples and the results of engineering surveys and tests. Four types of potential hazard are classified: locally fluidized core with a high water content, rapid water inflow to a borehole, cores with granular materials, and relatively low stiffness of core. Among these, the locally fluidized core is the most critical hazard that requires remedial action because it is related to the potential internal flow path and internal erosion. The other three hazard types are of medium importance and require careful monitoring and regular inspection. Of note, there was no correlation between age and core deterioration. The results are expected to aid the safe management and potential upgrading of aging cored fill dams.

• The Journal of Engineering Geology
• /
• v.17 no.3
• /
• pp.471-481
• /
• 2007

The Landslide in natural slope is occurred mostly by a heavy rain of the summer. This landslide is influenced in soil property of the surface than the rock mass. Soils in natural slope are created by weathering phenomena of the bedrock. These soils differed to the geological conditions such as sedimentary rock, metamorphic rock and volcanic rock. Therefore, estimation of landslide in natural slope is the most important analysis of the bedrock distributions and soil characteristics. This study analyzed the soil property to the natural slopes of Busan area where is distributed to volcanic rock, granite and sedimentary rock. Soil sample conducted various soil tests for estimate the soil physical property and soil engineering characteristics, and analysis of the correlation of geological conditions. In the experiment result, soils were mainly classified by a clayey sand. It is also established that $1.07{\sim}1.99kg/cm^3$ for wet density, $28.2{\sim}39.6^{\circ}$ for angle of shearing resistance, and $8.10{\times}10^{-5}{\sim}8.38{\times}10^{-2}cm/sec$ for coefficient of permeability. From the physical parameter, the soils are estimated to the permeable ground with good shear strength, and soil properties are showed a differential tendency for each geological condition.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.28 no.2
• /
• pp.75-80
• /
• 2008

To investigate the sulfate utilization efficiency that has been examined in rape (Brassica napus L.) cultivars (cv. Akela and Colosse). During 72h of treatment, in two cultivars, ${SO_4}^{2-}$ uptake was significantly higher in complete S condition (2.0 mM ${SO_4}^{2-}$) than that of the S-deficient condition (2.0 mM ${SO_4}^{2-}$). In young leaves, ATP sulfurylase activity increased after S-deficient treatment. However, in old leaves, ATP sulfurylase activity was not significantly changed in Akela. Glutathione concentration in young leaves significantly increased in all cultivars examined under S-deficient condition. The rate of increase in glutathigne concentration caused by S-deficiency treatment was higher in Akela. However, in old leaves, the glutathione concentration in Akela significantly decreased. The results suggest that ${SO_4}^{2-}$ uptake and ATP sulfurylase in rape plants were species specific, and that ${SO_4}^{2-}$ uptake was highly related to its assimilation into S containing compound such as glutathione.

• Journal of Food Hygiene and Safety
• /
• v.25 no.2
• /
• pp.180-184
• /
• 2010

This study surveyed the change of housewives' purchase behaviors by food safety incidents; the outbreak of 2008 Melamine incident in Korea as for example. 565 housewives in Gunsan were interviewed in March 2009. 52.3% of respondents were regarded as unsatisfactory for food safety management in Korea. Despite the result of scientific assessment for melamine, 74.6% of respondents were yet regarded as health-threatening substance. By the point of before, during and after Melamine-related food safety incident, we were surveyed the level of purchase for melamine-related food items as five scales, the results were $2.47{\pm}0.97$, $1.80{\pm}0.92$ and $1.62{\pm}0.92$, respectively (p < 0.001). After the incident happened, the purchase level was even more reduced. This study also found that there were significance difference (p < 0.05) among the respondents' knowledge for melamine toxicity and food safety management in Korea concerning housewives' purchase behaviors, i.e. the more accurately for melamine toxicity and higher satisfactory of consciousness of food safety, there were less change of purchase behaviors. In conclusion, the consciousness of food safety and accurate knowledge of hazards were significantly affected for the change of housewives' purchase behaviors by food safety incidents. Therefore, it can be suggested that the need for more scientific risk communication strategies with consumer.

• Journal of Food Hygiene and Safety
• /
• v.28 no.4
• /
• pp.312-318
• /
• 2013

This study validated microbiological hazards of ginseng farms at the cultivation stage and suggested recommendations to develop a good agricultural practices (GAP) model. A total of 96 samples were collected from cultivation environments (soil, irrigation water, and atmosphere), plants (ginseng and its leaf), personnel hygiene (glove, cloth, and hand) of 3 ginseng farms (A, B, and C) and were tested to analyze sanitary indicator bacteria (aerobic plate count, coliforms and Escherichia coli), major foodborne pathogens (E. coli O157:H7, Listeria monocytogenes, Salmonella spp., Staphylococcus aureus, and Bacillus cereus), and fungi. Total bacteria, coliform, and fungi in the 3 ginseng farms were detected at the level of 1.3~6.0, 0.1~5.0, and 0.4~4.9 v/g (or mL, hand, and $100cm^2$), respectively. Only irrigation water collected from one ginseng farm was confirmed to be E. coli positive. In case of pathogenic bacteria, B. cereus was detected at levels of 0.1~5.0 log CFU/g (or mL, hand, and $100cm^2$) in all samples, but other pathogen bacterias were not detected in any samples from all farms. Although E. coli were detected in irrigation water, the level of microbial for the three farms was lower than the regulation limit. According to the results, the ginsengs produced from the 3 farms were comparatively safe with respect to microbiological hazard. However, cross-contamination of bacteria from environments and workers to ginseng has been considered as potential risks. Therefore, to minimize microbial contamination in ginseng, GAP model should be applied for ensuring the safety of ginsengs.

• Korean Journal of Food Science and Technology
• /
• v.35 no.5
• /
• pp.998-1002
• /
• 2003

Agricultural foodstuffs, usually consumed without sterilization, are frequently contaminated with foodborne pathogen B. cereus. Ethanol and sodium chloride were used to inhibit this pathogen for its effective control. Though five minutes of exposure to 20% ethanol did not inhibit the growth of B. cereus, inhibition was detected to 30% ethanol solution. As exposed longer, B. cereus was more effectively inhibited than E. coli and S. typhimurium. B. cereus, E. coli and S. typhimurium were not inhibited when exposed in a 10% sodium chloride solution for five minutes. However, these bacteria were inhibited with a combination of 10% sodium chloride and 20% ethanol solution for five minutes. Much synergistic growth inhibition on B. cereus was found at the treatment. Its viable count was reduced from $10^8cfu/ml$ to $10^2cfu/ml$ after five minutes and showed no count after ten minutes. This trend was also confirmed for the wild types of B. cereus. This method may be applied for the effective pre-treatment of many agricultural foodstuffs, especially uncooked foodstuffs, without the hazards that accompany special sanitizers and the nutritional loss from harsh sterilization.