This study first addresses the ineffectiveness of indirect regulation on industrial machines. Analysis of causes of industrial accidents associated with industrial machines further reveals the fact that technical causes need to be resolved at the manufacturing stage to reduce the frequency and strength of industrial accidents. Balanced safety certification on manufacturers and safety inspection on users of industrial machines are then suggested to effectively resolve such technical causes. The effectiveness of such safety certification and safety inspection can be justified by cost-benefit analysis. Particularly, balance in expected benefits of safety certification and safety inspection is a key issue for validity of such analysis. The accumulated benefit-costs for press brake and portable sawing machine confirm the effectiveness of such safety system.

The experimental design methodology was applied in the drop tube furnace (DTF) to predict the various combustion properties according to the operating conditions and to assess the coal plant safety. Response surface method (RSM) was introduced as a design of experiment, and the database for RSM was set with the numerical simulation of DTF. The dependent variables such as burnout ratios (BOR) of coal and $CO/CO_2$ ratios were mathematically described as a function of three independent variables (coal particle size, carrier gas flow rate, wall temperature) being modeled by the use of the central composite design (CCD), and evaluated using a second-order polynomial multiple regression model. The prediction of BOR showed a high coefficient of determination (R2) value, thus ensuring a satisfactory adjustment of the second-order polynomial multiple regression model with the simulation data. However, $CO/CO_2$ ratio had a big difference between calculated values and predicted values using conventional RSM, which might be mainly due to the dependent variable increses or decrease very steeply, and hence the second order polynomial cannot follow the rates. To relax the increasing rate of dependent variable, $CO/CO_2$ ratio was taken as common logarithms and worked again with RSM. The application of logarithms in the transformation of dependent variables showed that the accuracy was highly enhanced and predicted the simulation data well.

A Large Eddy Simulation(LES) was performed for the prediction of unsteady dispersion behavior of hydrogen fluoride (HF). The HF leakage accident occurred at the Gumi fourth industrial complex was numerically investigated using the Fire Dynamics Simulator (FDS) based on the LES. The accident area was modeled three-dimensionally and time-varying boundary conditions for wind were adopted in the simulation for considering the realistic accident conditions. The Message Passing Interface (MPI) parallel computation technique was used to reduce the computational time. As a result, it was found that the present LES simulation could predict the unsteady dispersion features of HF near the accident area effectively. The dispersion behaviors of the leaked HF was much affected by the unsteady wind direction. The LES could predict the time variation of the HF concentration reasonably and give an useful information for the risk analysis while the prediction with the time-averaging concept of HF concentration had a limitation for the amount of HF concentration at specific location point. It was identified that the LES is very useful to predict the dispersion characteristics of hazardous chemicals.

In this study, interfacial characteristics between SOFC and Ag paste as current collector was estimated in the high temperature environment. The Ag paste was used to connect the unit cell of SOFC strongly with interconnector and provide the electrical conductivity between them. To confirm electrical conductivity, Ag paste was treated in the furnace at $800^{\circ}C$ for 48 hours. The sheet resistance of Ag paste was measured to compare the resistance values before and after the heat treatment. Also, the four-point bending test was performed to measure the interfacial adhesion. The unit cell of SOFC and $SiO_2$ wafer were diced and then attached by Ag paste. The $SiO_2$ wafer had the center notch to initiate a crack from the tip of the notch. The modified stereomicroscope combined with the CCD camera and system for measuring the length was used to observe the fracture behavior. To compare the characteristics before heat treatment and after heat treatment, the specimen was exposed in the furnace at $800^{\circ}C$ for 48 hours and then the interfacial adhesion was evaluated. Finally, the interfacial adhesion energy quantitatively increases $1.78{\pm}0.07J/m^2$ to $4.9{\pm}0.87J/m^2$ between the cathode and Ag paste and also increase $2.9{\pm}0.47J/m^2$ to $5.12{\pm}1.01J/m^2$ between the anode and Ag paste through the high temperature. Therefore, it is expected that Ag paste as current collector was appropriate for improving the structural stability in the stacked SOFC system if the electrical conductivity was more increased.

Three phase heaters in 7 buildings of 2 sites were examined for precise diagnosis. The sample size was 626. Precise examinations of current and the heater wiring status revealed contact failures and arcs in equipments that had CUF larger than 10%. Contact failures and arcs may cause electrical fire. Therefore, the correlation between the CUF and the imperfections in heater equipment and its wiring was analyzed for three phase heaters. In addition, the protection devices used for detection of heater imperfections were found to be unsuitable for the purpose. Current status of the protection devices was analyzed, and suggestions for improvements were made for new standards of the protection device selection.

The feasibility of recycling wasted printed circuit board (PCB) is investigated by preparing PCB added flame retardant composites filled with either unsaturated polyester or polyurethane. In order to improve electroconductive properties, copper powder was added into the composites, which results also in improving their antistatic properties. The prepared composite samples showed a binding between the polymer fillers observed by a scanning microscope. The sample group using unsaturated polyester is elastomeric that led to appreciable elongation and elasticity. In case of polyurethane, the tensile strength increased proportionally as increase of the amount of PCB powder. The composite materials can be utilized as antistatic composite materials, since the surface resistivity result showed increase of the electroconductive properties by adding Cu. The flammability of the samples is not satisfactory according to UL-94 vertical test. However, the flame retardant properties were improved by adding PCB power. This study, therefore, showed that it is feasible to fabricate polymer composite materials and improve the material characteristics by adding PCB powder, which can replace existing additives used for the preparation of polymer composite materials and can reduce the environment contamination by recycling the wasted PCB.

Many construction equipment or supporting structure should be installed in a field without appropriate anchorage to cause a collapse of those. Anchor length, anchor diameter, hooked or non hooked will be made and tested in the study. This one will be analyzed and compared with the previous study in order to find out some difference, strength by strength, based on this study. Embedded re-bar and the resistant capacity against pulled out force of re bar have been tested and analyzed by concrete design strength and rebar diameter in the study. 21Mpa and 24MPa compressive strength which are used in construction practice have been applied as variables. Those rebars are composed of D13, D16. D22 which are mostly used at construction sites. The followings are summarized as conclusions.1) ductility is not increased as rebar diameter becomes larger under the condition of non-hooked anchorage.2) those are two times of displacement difference between small diameter of rebar and large one with hooked anchorage of rebar while being 1/10 times difference with non-hooked condition but, only 10% difference of maximum load are shown, not conspicuously between hooked and non-hooked condition.3) displacement related to ductility can be three(3) times decreased if only concrete compressive strength and rebar diameter become larger with heavy support weight.

In the study, a new non-open cut tunnel steel pipe method using slot hole has been developed. As is overcomes shortcomings of conventional methods, it is applied to the field. The main concept of the new method is the steel pipe pumping system with slot holes which, by means of formation slot holes between each steel pipe, applied to the magnitude of the relaxed earth pressure caused by excavation to the ground to prevent ground displacement. The stability of the support members and effect of displacement control of the new method were verified through several ways as numerical analysis and site test. The new method was applied to the construction of a 11.5m wide, 7.4m high and 50m long section that passes side subway and large buildings in inner city. By applying the new method, tunnel construction was successfully completed in 6 months. It decreases the construction period to 30% compared to that of conventional methods, and ground was almost negligible.

The aim of the paper is to introduce the statistical definition of the specified compressive strength of the concrete to be used for safety evaluation of the existing structure in domestic practice and to present the practical method to obtain the specified strength by utilizing the non-destructive test data as well as the limited number of core test data. The statistical definition of the specified compressive strength of concrete in the design codes is reviewed and the consistent formulations to statistically estimate the specified strength for assessment are described. In order to prevent estimating an unrealistically small value of the specified strength due to limited number of data, it is proposed that the information from the non-destructive test data is combined to that of the minimum core test data. The the sample mean, standard deviation and total number of concrete test are obtained from combined test data. The proposed procedures are applied to an example test data composed of the artificial numerical values and the actual evaluation data collected from the bridge assessment reports. The calculation results show that the proposed statistical estimation procedures yield reasonable values of the specified strength for assessment by applying the non-destructive test data in addition to the limited number of core test data.

This study is to explore floor impact sound and sound insulation of reinforced concrete structure with void-deck slab system which combines polystyrene void foam and T-shaped steel deck plate. A void-deck slab system can effectively reduce the amount of concrete used and hence the mass of a reinforced concrete slab. Also void slab system has dynamically favorable for bending. Three-bay 2-story building was constructed as a mock up test specimen using void-deck slab system and floor impact sound was measured to valuate sound insulation performance. Light weight floor impact and heavy weight floor impact were investigated. Light weight floor impact pressure levels were 32dB, 28dB, and 29db at representative locations which are $1^{st}$ level in the floor impact sound insulation performance grading system. The heavy-weight floor impact pressure levels were 44dB, 45dB, and 43dB at representative locations which are $2^{nd}$ level in the floor impact sound insulation performance grading system. Therefore void-deck slab system can be used in public housing apartment building in terms of not only effectively reduced construction materials but also floor impact sound insulation.

Safety, resilience and comfort of pedestrian were assessed by the British Pendulum Test and SB/GB factor test at 8 kinds of sidewalk pavement. Sidewalk paving materials were normal concrete, porous concrete, concrete block, soil concrete, asphalt, rubber chip/resin mixture, wood chip/resin mixture and floor tile. In addition, a survey was conducted to investigate the perception of pedestrians on the sidewalk paving material. As a result, while the skid resistance value was measured in the most 60BPN above, the floor tile showed a low value of about 30BPN. The ratios of SB factor to GB factor of the elastic pavements(rubber/resin mixture and wood chip/resin mixture) appeared to be relatively large when compared with those of the conventional sidewalks. The survey showed that respondents perceived as more safe and comfortable elastic pavements compared to conventional pavements. Approximately 50% of respondents answered that hardened soil pavement was the most environmentally friendly.

According to the report of the WHO, workers have been exposed to much job strain such as job load, responsibility, role, interpersonal conflict etc. In Korea, studies on job strain started to become active from 1990s and now hundreds of studies are actively under going or publishing so that the studies are contributing to development and improvement of job strain. Representative measurement models of job strain are Job Strain Model of Karasek, Job Stress Model of NOISH, Korea Occupational Stress Scale, JSQ(Job Stress Questionnaire), K-OSI(Korea Version of Occupational Stress Inventory) etc. (Lee Kwan-Suk, 2012 ; KOSHA, 2003). Among them, Job Strain Model of Karasek had been loved by many researchers of job strain before Korea Occupational Stress Scale was developed. Job Strain Model of Karasek had been fitted to Korean style and then, used to analyze job strain of Korean people so that this Scale highly contributed to seeking relationship with cardiovascular disease, musculoskeletal disease caused by job, smoking, drug, alcohol poisoning, and pulse(Lee Kwan-Suk, 2012). But as this Model was studied and developed based on foreign culture and life pattern, a model fit to Korea was developed to measure job strain for Korean people, which is Korea Occupational Stress Scale now most frequently used in measuring job strain. Accordingly, after this study made questionnaire survey about same population using the two methods used most frequently in measuring job strain, the study investigated what features appeared, what correlations appear between two models, and comparatively analyzed characteristics each independent and dependent variable. Based on this, the study aimed to exactly express job strain of Korean people. The subjects of the study were a population of 233, and Karasek's Questionnaire and KOSS's Questionnaire were surveyed at the same time. The results were analyzed by statistical program to obtain significant difference between two models. Four particular groups were divided with Job Strain Model of Karasek and the four particular groups were measured with Korea Occupational Stress Scale. And job strain come from combination of two models was measured, with which new comparative analysis method was suggested.

This research proposed a design direction for the ambulance interior storage space based on the placement and access to the equipment to facilitate an emergency medical practice taking into account the safety and efficiency by the emergency medical technician ergonomic factors. Therefore, through a field survey for the current derivation of the storage space problem 'placement', 'enable', 'management' like these three items resulting clarity, accessibility, simplicity and functionality of the four functional elements by targeting ambulances in operation in this country. First, there is a need to improve standardized of cabinet sizes fit to loaded meet emergency equipment standards. Currently, the equipment designed to use a simple storage cabinet has had problems in the usability. Second, it must be located in the continuous exposure in progress to the user's traffic line. Third, the problem was the insufficient function of the cabinet to ensure the safety of patients by paramedics from the emergency rescue equipment and due to the leaning of the ambulance driving. Besides, it was pointed out that in addition to the proposed alternatives, including the agenda, states that safety belt replacement equipment, emergency personnel and patients with the handle of a guardian for the efficient use storage space within the 119 ambulance. However, in the present study suggest that there is a state proceeds mainly limited usability in the field, having been installed.

Most incidents and accidents involved human during operating NPPs have a tendency to be structured by complicated and various organizational, individual, and environmental factors. The salient feature of the human error in NPP was extremely low frequency, extremely high complicated and extremely serious damage of human life and property. Our research team defined as 'rare human errors'. To prevent the rare human errors, the most researchers and analysts insist invariably that the root causes be made clear. The making them clear, however, is difficult because their root causes are very various and uncertain. However, These tools have limits that they do not adapt all operating situations and circumstances such as design base events. The purpose of this study is to improve the rare human error hazards consider the situational contex. Through this challenging try based on evidences to the human errors could be useful to prevent rare and critical events can occur in the future.

This study analyzes the influence factors on elderly pedestrian accident. Elderly people are easy to be badly injured by car accidents compared to younger people. Therefore, various plans and measures are required to protect elderly pedestrian from accidents. However, pedestrian accidents studies only focused on microscopic factors such as attribute of driver, pedestrian, road design. In order to prevent pedestrian accident and reduce the severity of the accident, not only microscopic factors but macroscopic variables such as urban planning and facility should be considered. In this regard, this study develops an ordered probit model introduced the characteristics of urban facility which were not considered in the previous studies. The result shows that there is higher level of accident severity in such areas as large commercial area, well-developed area with transportation infrastructure service and non-pedestrian safety zone. Thus, various and appropriate countermeasures should be prepared in order that pedestrian accident can be prevented in the areas mentioned above. In addition to the aforementioned variables, it is revealed that other variables including vehicle speed, gender and age of pedestrian, weather condition, type of vehicle, etc. partly affect the severity of pedestrian accident.

This study deals with the roundabout accidents. The goal of this study is to develop the sideswipe accident models at roundabout. In the pursuing the above, this study gives particular attentions to collecting the data of geometric structure and accidents of 54 roundabouts in Korea and developing the Poisson and negative binomial regression models. The main results are as follows. First, sideswipe accident is analyzed to be the highest frequency that is 39.5% of total accident data. Second, Poisson models which is statistically significant is developed. Finally, traffic volume per approach($X_1$), number of circulatory roadway($X_3$), operation of parking lot($X_4$) and width of circulatory roadway($X_6$) are adopted as the common variables. This study might be expected to give some implications to the accident research on the roundabout.

In this study, we carried out the emissions analysis of CO and $non-CO_2$ for the age-classes of various pine trees(Pinus koraiensis, Pinus densiflora, Pinus rigida Mill., Pinus thunbergii Parl.) to estimate of emission factors of the crown layer and surface layer in the forest fire. We used the thermal characteristic analyzer cone heater and NDIR analyzer in order to measure amount of emission. As a result, the major emissions of Pinus koraiensis were $CO_2$ and $CH_4$ and that of Pinus thunbergii Parl. was only CO. The major emissions of the most of pine trees were NO and $N_2O$. The $CO_2$ emission of Pinus thunbergii Parl. was the highest about as $7.26{\times}10^{-2}{\sim}1.63{\times}10^{-1}g$ and next came Pinus densiflora, Pinus koraiensis, Pinus rigida Mill.. And the CO emission of Pinus thunbergii Parl. was about $5.14{\times}10^{-3}{\sim}6.58{\times}10^{-3}g$ and followed by Pinus densiflora, Pinus koraiensis, Pinus rigida Mill.. The emissions of $CH_4$, NO, and $N_2O$ showed small differences between species and the emission of $CH_4$ was $8.37{\times}10^{-5}{\sim}2.55{\times}10^{-4}g$, and NO was $6.65{\times}10^{-5}{\sim}2.0{\times}10^{-4}g$ and $N_2O$ was $1.42{\times}10^{-4}{\sim}2.09{\times}10^{-3}g$ in all species. Particularly, the emission of Pinus thunbergii Parl. was the highest in all pine trees except $CH_4$.

The primary purpose of the general duty clause is to offer an extra measure of protection to employees in the workplace. Most standards implemented under OSHA are targeted at a specific hazard. The general duty clause, however allows inspectors to cite employers for exposing its employees to a recognized hazard that has not been specifically addressed in the regulations. Congress intended the general duty clause to be a limited means of advancing the purposes of the OSHAct. But OSHA has not always regarded the general duty clause as the limited means for protecting the safety and health of employees that Congress intented. OSHA attempted to expand the scope of the general duty clause, at times improperly, to make it a more flexible enforcement tool. OSHA's interpretation of each of the restrictions on the scope of the clause has changed over the years. In recent years the general duty clause has been utilized as a sometimes controversial mechanism for enforcement of safety guidelines that have not yet been specifically addressed by statute or regulation. The most notable example of this was application of the general duty clause to ergonomic hazards.

This study has analyzed city plans and disaster prevention plans from the perspective of resilience and established a direction of the development of city safety standards. The analysis made use of the 5 functions of resilience (5Rs) and foreign cases. As a result of the analysis, the direction of the development of city safety standards was drawn from 4 perspectives at large. First, this study proposed a method of the systematization of the safety standards involved in components within city plans. Second, it suggested a method to strengthening urban resilience abilities in terms of the association between disaster prevention and city plans. Third, it found out components requiring safety standards considering foreign and other standards, and proposed a direction of complementary measures for safety standards. Lastly, it came up with a direction of the development of city safety standards, the necessity of which are required though existing plan criteria did not contain them. This study is significant in that it has defined the ultimate goal of safety a city should pursue as resilience and proposed a direction of the development of related standards.

Fire fighter are exposed to the situations which are hard to predict due to continuous and accidental changes which hinder their fire fighting activity. As these threats of safety accident act as fear factors, they are doing insecure fire fighting activities. Therefore, as unclear and abnormal risks of working environment such as the riskiness of expansion of disaster, instability, obstacles of activities, abnormality, urgency, etc. increase, safety accidents are caused. This study analyzes the actual condition of safety and health and awareness of fire fighter who are exposed safety accidents during their fire fighting activities and utilize such result as the basis data to secure safety of fire fighter, keep efficient safety control and prevent accidents. The results of analysis are as follows. As rescue works among all fire-fighting works shows the highest emotional stabilization and the highest post-traumatic stress disorder is shown in fire sergeant level positions, and fire fighters whose working period is 10-15 years, reinforcing safety training to long-term workers is necessary. As the result of survey regarding safety awareness, the highest awareness level was shown in fire sergeant level positions, and fire fighters whose working period is over 20 years, and when it comes to operation of fire fighting equipments, fire-fighting workers and workers having 1-4 years of working period showed high safety awareness. The more serious injury in a fire fighter experienced as the first injury after working as a fire-fighter, the more cause-and-effect relationship was shown between personal physical condition and work, and it is shown as obstacles of fire fighting activities and affects to post-traumatic stress disorder. Moreover, as after-work off duty activities also affect to official disaster, systematic improvement of working environment is required. Occupational medical work compatibility evaluation considering the distinct characteristics of works to secure fire-fighter' health care together with fire-fighting capability is shown to be necessary.

This study aims to quantitatively evaluate failure pressure of wall-thinned elbow under combined load along with internal pressure, by conducting real-scale burst test and finite element analysis together. For quantitative evaluation, failure pressure data was extracted from the real-scale burst test first, and then finite element analysis was carried out to compare with the test result. For the test, the wall-thinning defect of the extrados or intrados inside the center of 90-degree elbow was considered and the loading modes to open or close the specimen maintaining a certain load or displacement were applied. Internal pressure was applied until failure occurred. As a result, when the bending load was applied under the load control condition, the intrados of the defect was more affected by failure pressure than the extrados, and the opening mode was more vulnerable to failure pressure than the closing mode. When the bending load was applied under the displacement control, it was hardly affected by failure pressure though it was slightly different from the defect position. The result of the finite element analysis showed a similar aspect with the test. Moreover, when major factors such as material properties and pipeline thickness were calibrated to accurate values, the analytical results was more similar to the test results.