Objective: The purpose of this study is to contribute to the reduction of human error of captain and OOW for prevention of ship collision accident by investigating and statistically analyzing the factors of human error of the captain and OOW. Background: Ship collision accidents tend to increase every year, and the cause of ship collision in recent 7 years is 98% due to human error. However, there are few studies on the cause of navigation officer's human error in the ship collision accident. Method: This study collected and analyzed data of ship collision accident 109 cases, 218 ships and 218 captain and OOW from passenger ships and merchant ships over 500 tons from 2010 to 2016. Through cross tabulation analysis, causes of human errors in OOW were identified in ship collision situations. Results: As a result of analyzing the cause of collision caused by the OOW on 134 vessels, the main cause of give-way vessels were the neglect of lookout and watch-keeping (63.8%). The stand-on vessel did not carry out appropriate cooperation activities (64.6%). In the case of the captain, the most frequent cause of collision was the neglect of lookout and watch-keeping (46.4%). The first mate (45.2%) did not take appropriate cooperative action. In the case of the second and third mate, the cause of collision was the neglect of lookout and watch-keeping. The lookout neglect factor was the common cause in the give-way vessel and the stand-on vessel (51.5%). Conclusion: When encountering another vessel during the voyage, it is necessary to navigate thoroughly with naked eyes and radar, looking for the other vessel, and the maneuver to avoid collision should be active operation at a sufficient time. In this study, 109 cases of ship collision were caused by human error of captain and OOW. It is suggested that the captain and the second mate should pay special attention to the voyage because there are a relatively large number of cases in which the lookout was neglected. Application: The results of this study can be used to present guidelines for preventative measures for the captain and navigation officers in shipping industry including navigation safety and education/training.

Objective: This study aims to apply the concept of aging metaphor to personal service robots to deliver new experiences to users. Background: Personal service robots such as Softbank's Pepper and MIT Media Lab's Jibo have begun entering our lives. These service robots have the important function of interacting with human beings. Method: The robot aging metaphor is to transform the shape, color, motion, voice, and texture, which are visual, auditory, and tactile components, by applying the concept of aging to the robot interface. The robot applied with the concept of aging metaphor forms a close relationship with human beings and provides emotional value to them. We summarize herein the concept of robot aging metaphor and propose an application method using the system and feature of the natural aging process in the real world through the prototype. Results: Robot aging metaphor structure and applied researches of robot aging metaphor are suggested in designing robot interfaces. Conclusion: The results of the design framework of robot aging metaphor will help users to experience emotional value interacting with robots. The framework which is suggested should be applied to social robots in appropriate contexts. Application: Types of aging process which provides optimizing user experience for users should be validated through an experiment.

Objective: The aim of this study is to identify the problems of the current Korean Standards (KS) of student chairs and to propose a new KS based on the Korean student anthropometric data. Background: Korean students are dissatisfied with their chairs while they are studying for a long time. This is due to the problems with the size system and the dimensions of the chairs following the KS standards, which have been subject to Japanese standards and ISO standards for the long times without any verification. Therefore, it is required to propose new chair specifications considering the recent anthropometric data of Korean students. Method: This study aimed at presenting improvements only for seat height, seat depth and seat width of student chairs in KS G 2010 for student desks and chairs,. The anthropometric data of 8,011 pupils aged 7~18 years was used in this study. The ergonomic design principles for the chair dimensions were applied. To compare the current KS with the newly suggested KS proposal, the concept of accommodation ratio is proposed. Results: The current KS standards of student chairs could not accommodate a large number of students. To increase the accommodation ratio, the current seven size system was changed into the nine size system in the new proposal. Also the ergonomic principles have been applied to establish new dimensions of student chairs. As a result, the accommodation ratios of seat height, seat depth and seat width increased to 90.5%, 91.8% and 65.2% respectively. Conclusion: New standards for the student chairs based on the Korean anthropometric data were suggested. This new proposal showed great improvement in accommodation ratio of student chairs. Application: The result of this study can be applied to the establishment of new KS standards of student chairs.

Objective: The purpose of this study is to present basic data and guideline for prevention of disasters by analyzing the influential factors related to the causes of the disaster by industrial accidents. Background: Although there are many studies on the analysis of industrial accident factors, most studies controlled the descriptive statistical data such as the ratio and the number of cases, and there are not many studies on the exact cause analysis based on the inferential statistical analysis. Similarly, there are some studies such as traffic accident data analysis and accident analysis of the workers in the manufacturing industry. However, the cause analysis through the inferential analysis is rare. Therefore, in this study, the analysis is carried out to extract and analyze various factors for not specific industries but general and wide scope ones. Method: This study analyzed the most recent data of the Industrial Accident Cause Investigation Report issued by the Korea Occupational Safety and Health Agency (KOSHA). First, the cross-analysis between factors was executed by the descriptive data such as the status of each industry type by cause factors, industry type by accident pattern, cause factors by tasks, etc. Next, based on the result of the cross-analysis, we analyzed the significance on each factor and the relation between the factors. Results: The significant differences were showed among the factors, the industry type, business size, accident pattern, cause factors, task and part of body. Based on this, detailed suggestion points were derived from analysis of each factors. Conclusion: We analyzed the implications of various factors affecting the numbers and interpreted its meaning. In particular, we performed the process of selecting and analyzing relevant factors that could affect the entire industry, without limiting the scope to specific industries. Through this, we could derive much meaning on various disaster factors. Application: The results of this study can be used as basic data for suggesting ergonomics guidelines from various perspectives such as industry, disaster type, and cause of occurrence as well as facility investment and policy to reduce ergonomic industrial accidents.

Objective The aim of this study is to investigate whether visual aids can enhance decision outcomes for multi-attribute choice making problems with practical datasets. Background: Information visualization techniques have been used to develop visual aids to help consumers process the given information, thus improving decision outcomes by increasing decision quality. However, due to the fact that decision quality is difficult to measure, several studies used context-free data to minimize the impact of participants' preference structures to reduce subjective factors. To better understand whether these visual aids are effective in a more practical setting, we need to conduct studies using data with context. Method: The experiment was conducted as a between-subject study with two interfaces, SimulSort for the interactive visualization interface and Typical Sorting for the non-visual traditional interface. Each participant had three decision making trials and the decision-making quality was measured by selecting the nondominated option that is considered as the best choice. A total of 127 participants participated through an online experiment platform. Results: Using the SimulSort interface, the odds of selecting a nondominated option, compared to not selecting it, increased and has a significant effect. Both the interface and type of selected option had significant main effects on the time spent. A posthoc analysis revealed that the type of selected option had significant effect for the participants who used SimulSort by spending more time to make a decision, however, this effect was not present for the participants who used Typical Sorting. The participants were generally confident on their decisions while using both interfaces. Conclusion: The results revealed that SimulSort could enhance the probability of making a better decision than compared to Typical Sorting. The study also shows an effective way to conduct a controlled study that has an objective measure for decision making using data with context. Application: The results of the experiment can help implement visual aids to help consumers make better decisions in everyday life.

Objective: This study examines body pressure and subjective comfort for four different mattresses (latex, memory foam, soft multi-hardness polyurethane and hard multi-hardness polyurethane mattress) in three different sleeping postures (back lying, left side lying and right side lying sleeping posture). Background: Mattress is very significant for satisfactory sleeping and well-being life. Many people are suffering from the sleep disorder these days. Not enough studies have been performed for the mattress especially for recently developed cutting-edge mattresses. Method: Thirty five participants evaluated the mattresses in the different sleeping postures. Mean body pressures and peak body pressures were measured and analyzed for the study and subjective comfort of the mattresses was also assessed by the participants. Results: Mean body pressure of each mattress was significantly different. Memory foam mattress and hard multi-hardness polyurethane mattress showed significantly lowest and highest mean body pressure in the back lying posture. In the other sleeping postures, similar results were also observed. Peak body pressure of memory foam mattress was significantly lower than other mattresses. The participants assessed hard multi-hardness polyurethane mattress was less comfort comparing to the other mattresses. Conclusion: Memory foam mattress produced lower mean body pressure and higher comfort regardless sleeping posture. The relationship between softness and quality of mattress would be explored in the future study. Hardness of mattress would be related to the mean body posture and subjective comfort. Application: The hardness of a mattress could be adjusted to improve the quality of mattresses. The results of the study can be applied to develop new mattresses as well.

Objective: To develop a BARAW (By Avoiding Repetitive motions, Awkward postures and Weights) tool which can be applied to assess and improve the musculoskeletal discomfort and pain associated with nursing service workers. Background: Most of existing MSDs assessment tools were developed to investigate the repetitive works commonly found in manufacturing industry. A new approach is needed to assess such non-repetitive works as those done by nurses. Method: As the first step of developing BARAW tools, we investigated the existing assessment tools and guidelines for nurses. And then, BARAW tools were developed based on the results of the expert interview. Based on FGI (Focus group interview) and literature review, a questionnaire was developed to investigate the causes of the musculoskeletal discomfort and pain. Reliability of the questionnaire was tested. Results: The procedure of using the BARAW tool is as follows; 1) finding the cause of discomfort and pain 2) finding possible interventions, 3) implementation of the interventions, 4) evaluation of BARAW's effectiveness, 5) feedback. Very high reliabilities were obtained from the test. Conclusion: It was shown that BARAW tool developed in this research is a readily applicable to the works of nurses. Application: BARAW tool could be extended to other non-repetitive works.