Joohwan Kim

Mr. Joohwan Kim

Korea Maritime Transportation Safety Authority
orcid

Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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28 May 2021 in Sustainability
Verified
Journal Article
Open access
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JKJoohwan Kim
Joohwan Kim
HKHwayoung Kim
Hwayoung Kim
Safety is a key performance indicator for the sustainable management of a coastal ferry service business. An efficiency strategy that balances safety and transport performance should be considered. The purpose of this study is to evaluate the relative transport efficiency of coastal ferry operators through undesirable safety-related output. Coastal ferry operators create added value through logistics activities such as cargo and passenger transport. Accordingly, this study designed a three-stage network-slacks-based measure (SBM) model that delineated production through ferry transport services such as service generation, service execution, and transport value creation. Detention records and marine accidents caused by human errors or technical faults were considered undesirable safety-related outputs. Moreover, the relative transport efficiency of 23 Korean firms that have continuously managed a coastal ferry transport business from 2015 to 2018 was analyzed. The results showed that the differentiation of transport efficiency of firms improved when applying the three-stage network SBM model compared to applying the SBM model that did not consider the internal production stage. This fact suggests that it is more desirable to apply the three-stage network SBM model proposed in this study when a more stringent comparison of transport performance is needed in terms of service quality.

Verified
Journal Article
Open access
PDF file
JKJoohwan Kim
Joohwan Kim
Gunwoo LeeGunwoo Lee
Gunwoo Lee
HKHwayoung Kim
Hwayoung Kim
In the maritime transportation services industry, marine accidents may lead to fatalities, injuries, and property losses. Coastal ferry operators experience marine accidents and must pay attention to safety to guarantee the sustainability of their business. This study is aimed at analyzing the operational efficiency of coastal ferry operators in Korea from a safety perspective. We designed two slack-based measure of efficiency (SBM) models. One is a normal SBM, which includes only the total passenger volume as the desirable output. The other is a safety-constrained SBM, which includes marine accident records as an undesirable output with the desirable output of passenger transportation performance. We selected 44 coastal ferry operators in Korea that have been continuously operating for five years (2013–2017) as decision-making units (DMUs) and compared their operational efficiency scores. The results showed that the impact of marine accidents on business is greater in DMUs with lower transportation sales than in those with higher sales. This suggests that, while it is important for the government to strengthen safety regulations, a combination of policies that also help small ferry operators to stay in business in the long term is necessary to reduce marine accidents effectively while improving efficiency.

21 May 2024
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Conference Paper
Open access
STSamin Shahriar Tokey
Samin Shahriar Tokey
ZCZesheng Chen
Zesheng Chen
CMColin Mettler
Colin Mettler
DTDexuan Tang
Dexuan Tang
BBBen Boudaoud
Ben Boudaoud
MCMark Claypool
Mark Claypool
In first-person shooter (FPS) games, the peeker’s advantage is the edge the moving peeker gets when battling a stationary defender at a corner due to network latency. However, confirmation of (the size of) this advantage based on network latency and the distance from the corner has not been studied. This paper assesses the peeker’s advantage via two user studies both using an open-source FPS game extended to support two-player networking and a custom map. Users play as both peeker and defender with 3 different corner distances and 3 different network latencies. Analysis of hits, wins, and time-to-damage shows that the advantage for the peeker is impacted more by the defender’s latency than the peeker’s latency and is lowest when the peeker is nearest the corner. The user study with a tournament setting had quicker and more competitive matches resulting in more combat encounters and closer games than did the traditional user study.


1 May 2026 in Proceedings of the ACM on Computer Graphics and Interactive Techniques
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Journal Article
Open access
STSamin Shahriar Tokey
Samin Shahriar Tokey
BBBen Boudaoud
Ben Boudaoud
JKJoohwan Kim
Joohwan Kim
JSJosef Spjut
Josef Spjut
PXPeter Xenopoulos
Peter Xenopoulos
MCMark Claypool
Mark Claypool
Frametime spikes and graphical fidelity both matter for the feel of first-person shooter (FPS) games, yet their combined effects are not well understood. This paper examines how graphics settings and frametime spikes during aiming interact with player performance and experience. We developed a custom FPS game with configurable textures, lighting, and visual effects, and induced frametime spikes of 0 ms, 225 ms, or 675 ms during play. Twenty-one participants completed all combinations of graphics and spikes while providing performance data and subjective ratings for visual quality and smoothness. Results show that graphics quality primarily affects perceived visual quality , while frametime spikes primarily reduce perceived smoothness . Performance (i.e., score and accuracy) declines with larger spikes but remains largely unchanged across graphics settings. These findings suggest that spike magnitude, rather than graphics quality, is the dominant factor shaping smoothness and performance, while players still notice higher-quality graphics.

1 January 2023 in Journal of Marine Science and Technology
Verified
Journal Article
Open access
PDF file
JKJoohwan Kim
Joohwan Kim
SYSanglok Yoo
Sanglok Yoo
In this study, a comprehensive index for evaluating the degree of coastal traffic safety by simultaneously considering marine accident frequency, severity, and traffic volume was considered. To do so, the concept of Equivalent Property Damage Only (EPDO), which is widely used in the road transportation industry, was benchmarked to assess both frequency and severity of accidents. In addition, the total sailing distance of ships was chosen as a variable to explain traffic volume. Finally, a composite performance indicator called "M-EPDO per nautical mile" was built up, enabling the safety performance score for each type of ships in three criteria: on-board personnel safety, ship safety, and navigational safety, to be calculated. When the index was applied to 12 administratively-divided zones in Korea waters, the most vulnerable zone for safety and the type of ship with the lowest level of each criterion could be identified based on the index scores. Consequently, it is expected that this index will be an effective decision-making tool for selecting key targets to promote coastal traffic safety performance.