• The Korean Journal of Applied Statistics
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• v.29 no.1
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• pp.113-122
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• 2016

Longitudinal data often occur in prospective follow-up studies. Joint model for longitudinal data and failure time has been applied on several works. In this paper, we extend it to the case where longitudinal data involve informative observation time process as well as competing risks survival times. We use a likelihood approach and derive an EM algorithm to obtain maximum likelihood estimate of parameters. A suggested joint model allows us to make inferences for three components: longitudinal outcome, observation time process and competing risk failure time. In addition, we can test the association among these components. In this paper, liver cirrhosis patients' data is analyzed. The relationship between prothrombin times measured at irregular visiting times and drop outs is investigated with a joint model.

• Journal of the Korean Institute of Gas
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• v.12 no.2
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• pp.110-117
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• 2008

The risks of the chemical facilities were estimated by the KS-RBI(Ver. 3.0) program supporting the quantitative cause analysis, and reduction method for the risks of the facilities was investigated. As a result, we could find that the risks of the facilities decrease with reducing the likelihood of failure (LOF) affected by demage mechanism, inspection number and effectiveness of inspection, and with reducing the consequence of failure (COF) affected by the ratings of the detection, isolation, and mitigation systems. Furthermore, high risks of the facilities would be decreased by reduction of the LOF and the COF simultaneously. Accordingly, the applied plant would be able to achieve the decrease of inspection and labor costs because of the decrease of consequences and inspection intervals through the reduction of risks.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.2
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• pp.309-315
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• 2021

Risks and uncertainty are unavoidable problems in management of projects. Therefore, project managers should not only prevent risks, but also have to respond and manage them. Risk management has become a critical interest subject in the construction industry for both practitioners and researchers. This paper presents critical risk factors of office building projects in the construction phase in Ho Chi Minh City, Vietnam. Data was collected through a questionnaire survey based on the likelihood and consequence level of risk factors. These factors fell into five groups: (i) financial risk factors; (ii) management risk factors; (iii) schedule risk factors; (iv) construction risk factors; and (v) environment risk factors. The research results showed that critical factors affecting office building projects are natural (i.e., prolonged rain, storms, climate effects) and human-made issues (i.e., soil instability, safety behaviors, owner's design change) and the schedule-related risk factors contributed to the most significant risks for office buildings projects in the construction phase in Ho Chi Minh City. They give construction management and project management practitioners a new perspective on risks and risk management of office buildings projects in Ho Chi Minh City and are proactive in the awareness, response, and management of risk factors comprehensively.

• Architectural research
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• v.24 no.2
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• pp.21-27
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• 2022

For the past decade, South Korea had experienced catastrophic building fires, which resulted in consider-ably high number of casualties. This motivated research to develop fire-safe wall assemblies. In this study Fire Risk Analysis (FRA) is conducted as part of the project designing phase to ensure fire safety of the final product. Traditional approach was to consider fire performance at the end of the designing stage, when PASS/FAIL fire test results are required to be submitted to the Authority Having Jurisdiction (AHJ). By applying a fire risk analysis to guide the designing phase, overall fire safety of a wall assembly can be achieved more systematically as conducting FRA allows designers to clearly identify elements that are more vulnerable to fire and simply replace them with other practical options. Severity of fire risk is determined by considering the fire hazards of a wall assembly such as the exterior layer, insulation, vertical connectivity, and external ignition sources (e.g., photovoltaic panels). Frequency of fire risk is assessed based on the factors affecting fire likelihood, which are air cavity and fire-stopping applied in the design, and random design changes occurring during on-site construction. Fire risk matrix is proposed based on these fire risk factors and efforts to reduce the fire risk level associated with the wall assembly are given by systematically assessing the fire risk factors identified from fire risk analysis. Current study demonstrates how fire risk analysis can be applied to develop fire-safe walls by reducing the relevant fire risks- both severity and frequency.

• The Journal of the Korea Contents Association
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• v.8 no.10
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• pp.342-350
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• 2008

The study begins with the proposition that customers' recognition of risk and their information level for a service firm and its product influence to the selection of information channel and loyalty of customers. Experimental study found that the likelihood of personal information channel selection would be increased as customers felt higher level of risk and as they had lower level of information when they purchased service products. The study also found that customer loyalty would be influenced by the risk recognition level, but the relationship between loyalty and information level was not significant.

• Safety and Health at Work
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• v.8 no.1
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• pp.89-93
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• 2017

Background: Rates of overweight and obese Australians are high and continue to rise, putting a large proportion of the population at risk of chronic illness. Examining characteristics associated with preference for a work-based weight-loss program will enable employers to better target programs to increase enrolment and benefit employees' health and fitness for work. Methods: A cross-sectional survey was undertaken at two Australian mining sites. The survey collected information on employee demographics, health characteristics, work characteristics, stages of behavior change, and preference for workplace assistance with reaching a healthy weight. Results: A total of 897 employees participated; 73.7% were male, and 68% had a body mass index in the overweight or obese range. Employees at risk of developing obesity-related chronic illnesses (based on high body mass index) were more likely to report preference for weight management assistance than lower risk employees. This indicates that, even in the absence of workplace promotion for weight management, some at risk employees want workplace assistance. Employees who were not aware of a need to change their current nutrition or physical activity behaviors were less likely to seek assistance. This indicates that practitioners need to communicate the negative effects of excess weight and promote the benefits of a healthy lifestyle to increase the likelihood of weight management. Conclusion: Weight management programs should provide information, motivation. and trouble-shooting assistance to meet the needs of at-risk mining employees, including those who are attempting to change and maintain behaviors to achieve a healthy weight and be suitably fit for work.

• Safety and Health at Work
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• v.10 no.2
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• pp.172-179
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• 2019

Background: Workers exposed to hazards without adequate protections are at greater risk of injury and illness. Supervisor activities have also been associated with injury risk. We examined the interplay between supervisor safety support and occupational health and safety (OHS) vulnerability on workplace injury and illness. Methods: A survey was administered to 2,390 workers employed for more than 15 hrs/week in workplaces with at least five employees who had a direct supervisor. We examined the combined effects of hazard exposure with inadequate protection (OHS vulnerability) and supervisor support on workplace injury and illness, using additive interactions in log-binomial regression models. Results: OHS vulnerability and lack of supervisor support independently increased the likelihood of physical injuries at work. Crude and adjusted models showed that the risk of physical injury was at least 3.5 times higher among those experiencing both OHS vulnerability and a lack of supervisor support than individuals without OHS vulnerability and with a supportive direct supervisor. Workers who experienced vulnerability were at less risk if they had a supervisor who was supportive. Conclusion: In workplaces where workers experience one or more types of OHS vulnerability, having a supportive supervisor may play an important role in reducing the risk of injury and protecting workers.

• Journal of East Asia Management
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• v.3 no.1
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• pp.25-40
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• 2022

This study investigates the effect of labor union and its power on information opacity. Given that the information opacity ultimately leads to the stock price crash, this study examines the relationship between labor unions and future stock price crash risk. Further, by assuming a strike by labor union as the actual power of the unionization in firms, whether labor union's power subrogated by the activity (i.e., a strike) makes a significant difference in the likelihood of future stock price crash between unionized firms is also examined. The work place survey data provided by Korea Labor Institute is used to test the hypotheses. The data is for the periods of 2004 - 2012 on firms listed on Korea Stock Exchange and KOSDAQ. The results show that while labor unionization has a positive impact on future stock price crash risk, on which labor union's power has a negative impact. This means that the existence of labor union itself might facilitate firm's information to be opaque by tolerating manager opportunism, while its power mitigates the managerial opportunism, which leads to lower future stock price crash risk. This study adds to the literature on the role of labor unions as nonfinancial stakeholders and its power in accounting environment, and also on the determinants of stock price crash. It is also valuable to examine the unions' role in terms of the economic consequences of both presence and power of the labor unions.

• Journal of the Korean Institute of Gas
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• v.24 no.5
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• pp.1-9
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• 2020

In Korea, hydrogen stations are being promoted and commercialized. However, the risk assessment for the hydrogen station is not clear. In particular, it is not clear how to calculate the risk and acceptable criteria for a hydrogen station. Therefore, in this study, three hydrogen stations being installed were selected and general risks were calculated and the social risk of each hydrogen station was calculated. In general, the method of risk assessment is individual/social risk. This is an individual's death rate considering the frequency of accidents, And the likelihood of death according to the number of nearby residents. These can be used to calculate the level of risk for a hydrogen station. However, this method of calculate risks is the criteria for judging whether it is acceptable are unclear. For this reason, this study investigated the allowable standards for foreign risks and considered that they were acceptable by applying the risks of selected domestic hydrogen stations.

• Safety and Health at Work
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• v.11 no.2
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• pp.193-198
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• 2020

Background: Medical laboratory workers are frequently exposed to a wide range of chemicals. This exposure can have adverse effects on their health. Furthermore, a knowledge lack of the chemical risk increases the likelihood of exposure. The chemical risk assessment reduces the risk of exposure to hazardous chemicals and therefore, guarantees health and safety of the workers. Method: The chemical risk assessment was conducted using a modified INRS method, according to the new CLP Regulation, of 11 unit laboratories in a Moroccan medical laboratory. Observation of each workstation and analysis of safety data sheets are key tools in this study. Results: A total of 144 substances and reagents that could affect the health of the analytical technicians were identified. Among these products, 17% are concerned by the low priority risk score, with 55% concerned by the average priority risk score and 28% concerned by the high priority risk score. This study also enabled to better identify the chemical agents that have restrictive occupational exposure limit value and controls were conducted to this effect. On the basis of the results obtained, several corrective and preventive measures have been proposed and implemented. Conclusion: Risk assessment is essential to ensure the health and safety of workers and to meet regulatory requirements. It enables to identify all the risky manipulations and to adopt appropriate preventive measures. However, it is not a one-time activity but it must be continuous in order to master the changes and thus ensure the best safety of all.