• Journal of the Korean Society for Marine Environment & Energy
• /
• v.10 no.4
• /
• pp.201-210
• /
• 2007

Pollution by chemical substances such as POPs, EDCs and PBTs in the ecosystem has become more complex and varied, increasing the possibility of irreversible damage to human health or the ecosystem. It is necessary to have a exposure assessment in a multi-media environment for various chemical substances is required for efficient management. This study applied MUSEM(Multi-media Simplebox-systems Environmental Model), a multimedia environmental model that can simultaneously evaluate the possibility of exposure of hundreds of chemical substances in order to efficiently manage chemical substances that can have negative impact on human health or ecological environment through environmental contamination. MUSEM executed the modeling for Japan by setting all 47 prefectures of japan as the regional area for 62 chemical substances and the rest of the territory of japan, excluding regional area, as the continental area and made the estimation of concentration among environment media in each administrative area and made the sensitivity analysis on Tokyo area. The results of simulation for chemical distribution showed that most of the target chemicals located in water region. The result of sensitivity analysis for octanol-water partition rate showed that the concentration change of soil in urban/industrial area and sediment in freshwater was high. In the case of sensitivity analysis for degradation rate showed that the concentration change of freshwater, soil in urban/industrial area, and sediment in freshwater was high.

• Computers and Concrete
• /
• v.25 no.6
• /
• pp.497-507
• /
• 2020

This paper presents a numerical method for evaluating fire performance of prestressed concrete (PC) T shaped bridge girders under combined effect of structural loading and hydrocarbon fire exposure conditions. A numerical model, developed using the computer program ANSYS, is employed to investigate fire response of PC T shaped bridge girders by taking into consideration structural inherent parameters, namely; arrangement of prestressing strands with in the girder section, thickness of concrete cover over prestressing strands, effective degree of prestress and content of prestressing strands. Then, a sequential thermo-mechanical analysis is performed to predict cross sectional temperature followed by mechanical response of T shaped bridge girders. The validity of the numerical model is established by comparing temperatures, deflections and failure time generated from fire tests. Through numerical studies, it is shown that thickness of concrete cover and arrangement of prestressing strands in girder section have significant influence on the fire resistance of PC T shaped bridge girders. Increase in effective degree of prestress in strands with triangular shaped layout and content in prestressing strands can slow down the progression of deflections in PC T shaped bridge girder towards the final stages of fire exposure, to thereby preventing sudden collapse of the girder. Rate of deflection based failure criterion governs failure in PC T shaped bridge girders under most hydrocarbon fire exposure conditions. Structural inherent parameters incorporated into sectional configuration can significantly enhance fire resistance of PC bridge girders; thus mitigating fire induced collapse of these bridge girders.

• Journal of Biomedical Engineering Research
• /
• v.41 no.4
• /
• pp.147-153
• /
• 2020

This study was to evaluate the usability of self-developed phantom for evaluating automatic exposure control (AEC) using three-dimensions (3D) printer. 3D printer of fused deposition modeling (FDM) type was utilized to make the self-developed AEC phantom and image acquisitions were conducted by two different type of scanners. The self-developed AEC phantom consisted of four different size of portions. As a result, two types of phantom (pyramid and pentagon shape) were created according to the combination of the layers. For evaluating the radiation dose with the two types of phantom, the values of tube current, computed tomography dose index volume (CTDIvol), and dose length product (DLP) were compared. As a result, it was confirmed that the values of tube current were properly reflected according to the thickness, and the CTDIvol and DLP were not significantly changed regardless of AEC functions of different scanners. In conclusion, the self-developed phantom by using 3D printer could assess whether the AEC function works well. So, we confirmed the possibility that a self-made phantom could replace the commercially expensive AEC performance evaluation phantom.

• The Research Journal of the Costume Culture
• /
• v.25 no.1
• /
• pp.32-47
• /
• 2017

As the popularity of Korean drama and celebrities in China, Korean fashion is becoming increasingly popular in the Chinese market. Although the effect of Korean drama on Chinse consumers' attitudes toward Korean products are known, little research has been conducted to understand the mechanisms underlying the impact of Korean drama on the development of consumer attitudes. Thus, this study examines how Chinese consumers' exposure to Korean dramas has influenced their attitudes towards Korean fashion products. Applying the similarity-attraction theory, the study explores the roles Chinese consumers' perceived similarities in appearance and values with Korean characters in TV dramas plays in the process of attitude development. Data was collected via an online survey and the responses of 317 Chinese consumers in their twenties were used for data analysis. The results of structural equation modeling show that exposure to Korean dramas has a direct impact on Chinese consumers' perceived appearance similarity, perceived value similarity, image of Korean people, and attitudes toward Korean fashion products-results that support the theory of mere exposure. In addition, the analysis demonstrates that perceived appearance similarity positively influences the image of Koreans among Chinese people, which, in turn, influences attitudes toward Korean fashion products, supporting the similarity-attraction theory. However, the effect of perceived value similarity on attitude toward Korean fashion products was not significant. The study concludes by describing its practical implications for the Korean fashion industry and presenting ideas for future research.

• International Journal of Concrete Structures and Materials
• /
• v.11 no.2
• /
• pp.199-213
• /
• 2017

Chloride penetration is among the main causes of corrosion initiation in reinforced concrete (RC) structures producing premature degradations. Weather and exposure conditions directly affect chloride ingress mechanisms and therefore the operational service life and safety of RC structures. Consequently, comprehensive chloride ingress models are useful tools to estimate corrosion initiation risks and minimize maintenance costs for RC structures placed under chloride-contaminated environments. This paper first presents a coupled thermo-hydro-chemical model for predicting chloride penetration into concrete that accounts for realistic weather conditions. This complete numerical model takes into account multiple factors affecting chloride ingress such as diffusion, convection, chloride binding, ionic interaction, and concrete aging. Since the complete model could be computationally expensive for long-term assessment, this study also proposes model simplifications in order to reduce the computational cost. Long-term chloride assessments of complete and reduced models are compared for three locations in France (Brest, Strasbourg and Nice) characterized by different weather and exposure conditions (tidal zone, de-icing salts and salt spray). The comparative study indicates that the reduced model is computationally efficient and accurate for long-term chloride ingress modeling in comparison to the complete one. Given that long-term assessment requires larger climate databases, this research also studies how climate models may affect chloride ingress assessment. The results indicate that the selection of climate models as well as the considered training periods introduce significant errors for mid- and long- term chloride ingress assessment.

• Environmental Analysis Health and Toxicology
• /
• v.27
• /
• pp.8.1-8.10
• /
• 2012

Objectives: The goal was to model and quantify the atmospheric concentrations of volatile organic compounds (VOCs) as the result of the Hebei Spirit oil spill, and to predict whether the exposure levels were abnormally high or not. Methods: We developed a model for calculating the airborne concentration of VOCs that are produced in an oil spill accident. The model was applied to a practical situation, namely the Hebei Spirit oil spill. The accuracy of the model was verified by comparing the results with previous observation data. The concentrations were compared with the currently used air quality standards. Results: Evaporation was found to be 10- to 1,000-fold higher than the emissions produced from a surrounding industrial complex. The modeled concentrations for benzene failed to meet current labor environmental standards, and the concentration of benzene, toluene, orthometa- para-xylene were higher than the values specified by air quality standards and guideline values on the ocean. The concentrations of total VOCs were much higher than indoor environmental criteria for the entire Taean area for a few days. Conclusions: The extent of airborne exposure was clearly not the same as that for normal conditions.

• Asia pacific journal of information systems
• /
• v.18 no.4
• /
• pp.1-26
• /
• 2008

Rapid progress of information technology and widespread use of the personal computers have brought various conveniences in our life. But this also provoked a series of problems such as hacking, malicious programs, illegal exposure of personal information etc. Information security threats are becoming more and more serious due to enhanced connectivity of information systems. Nevertheless, users are not much aware of the severity of the problems. Using appropriate password is supposed to bring out security effects such as preventing misuses and banning illegal users. The purpose of this research is to empirically analyze a research model which includes a series of factors influencing the effectiveness of passwords. The research model incorporates the concept of risk based on information systems risk analysis framework as the core element affecting the selection of passwords by users. The perceived risk is a main factor that influences user's attitude on password security, security awareness, and intention of security behavior. To validate the research model this study relied on questionnaire survey targeted on evening class MBA students. The data was analyzed by AMOS 7.0 which is one of popular tools based on covariance-based structural equation modeling. According to the results of this study, while threat is not related to the risk, information assets and vulnerability are related to the user's awareness of risk. The relationships between the risk, users security awareness, password selection and security effectiveness are all significant. Password exposure may lead to intrusion by hackers, data exposure and destruction. The insignificant relationship between security threat and perceived risk can be explained by user's indetermination of risk exposed due to weak passwords. In other words, information systems users do not consider password exposure as a severe security threat as well as indirect loss caused by inappropriate password. Another plausible explanation is that severity of threat perceived by users may be influenced by individual difference of risk propensity. This study confirms that security vulnerability is positively related to security risk which in turn increases risk of information loss. As the security risk increases so does user's security awareness. Security policies also have positive impact on security awareness. Higher security awareness leads to selection of safer passwords. If users are aware of responsibility of security problems and how to respond to password exposure and to solve security problems of computers, users choose better passwords. All these antecedents influence the effectiveness of passwords. Several implications can be derived from this study. First, this study empirically investigated the effect of user's security awareness on security effectiveness from a point of view based on good password selection practice. Second, information security risk analysis framework is used as a core element of the research model in this study. Risk analysis framework has been used very widely in practice, but very few studies incorporated the framework in the research model and empirically investigated. Third, the research model proposed in this study also focuses on impact of security awareness of information systems users on effectiveness of password from cognitive aspect of information systems users.

• Journal of KIISE:Computer Systems and Theory
• /
• v.28 no.10
• /
• pp.491-498
• /
• 2001

We present a method of modeling lights from photographs taken with conventional imaging equipment. It does not use both any geometrical information and special apparatus to calculate surface reflection properties. To represent surface reflection properties of the scene, we use BRDFs which are calculated by radiance values of surface elements and light sources. And the BRDF data of each surface is further transformed to the spherical harmonic domain for efficient storage. Thus it allows to reconstruct the photo-realistic scene under different light sources, to manipulate diversely the arbitrary light source and to control exposure time of camera sensor. Moreover we test our algorithm with real image instead of synthetic image.

• Journal of Food Hygiene and Safety
• /
• v.15 no.3
• /
• pp.267-270
• /
• 2000

This study was designed to predict the risk of a hazard chemical, vinyl chloride, by applying dose-response assessment that are one of the major process in practicing risk assessment. After extrapolating from the high dose exposure of vinyl chloride based upon animal carcinogenic data to the low dose exposed to human using several mathematical models, we calculated the cancer potency factors as well as virtually safe dose and the resulted values were compared. This process will provide the new insight to assess the risk of a chemical accurately imposed to human in the future.

• Safety and Health at Work
• /
• v.6 no.4
• /
• pp.279-288
• /
• 2015

Background: In this study, the measurement of job stress of electric overhead traveling crane operators and quantification of the effects of operator and workplace characteristics on job stress were assessed. Methods: Job stress was measured on five subscales: employee empowerment, role overload, role ambiguity, rule violation, and job hazard. The characteristics of the operators that were studied were age, experience, body weight, and body height. The workplace characteristics considered were hours of exposure, cabin type, cabin feature, and crane height. The proposed methodology included administration of a questionnaire survey to 76 electric overhead traveling crane operators followed by analysis using analysis of variance and a classification and regression tree. Results: The key findings were: (1) the five subscales can be used to measure job stress; (2) employee empowerment was the most significant factor followed by the role overload; (3) workplace characteristics contributed more towards job stress than operator's characteristics; and (4) of the workplace characteristics, crane height was the major contributor. Conclusion: The issues related to crane height and cabin feature can be fixed by providing engineering or foolproof solutions than relying on interventions related to the demographic factors.