• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.108-109
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• 2022

In this study analyzed experimental data on noise interference caused by engine operating apply surface wave communication in the engine room. For the experiment, 7 areas of the engine room on 256 ton tug boat and measured noise during engine on off using signal analyzer for effect surface wave communication. In order to construct and actual communication network based on the analysis of the noise and confirm the characteristics of surface wave communication in the area made metal bulkheads the actual communication network installed communication equipment between three metal bulkheads and conducted a comparative experiment with wireless communication. The difference was confirmed. As a result, in the case of surface wave communication, there was no significant difference in the transmission and reception rates before and after engine operation in an environment with three bulkheads, but in the case of Wi-Fi using wireless, the performance deteriorated significantly during operation. was confirmed. As a result of analyzing the experimental data, it was confirmed that noise caused by engine operation affects wireless communication but does not affect surface wave communication. Therefore, even in the area with a lot of electromagnetic wave noise in the ship, when the surface wave communication system is configured using the ship's metal structure, it is possible to replace the wireless communication and furthermore, it is possible to apply the surface wave communication in the enclosed space and the engine room in the ship.

• Journal of Korea Port Economic Association
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• v.40 no.2
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• pp.191-204
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• 2024

In this study, AHP-based production management job training was developed for MPE companies in the aviation logistics industry. The AHP model was designed with upper and lower classes. Purchase management competency, material management competency, process management competency, and SCM competency were selected as factors of the upper class of production management job training. Lower class evaluation factors were selected for each upper class. As a result of AHP analysis, the relative importance of the upper class evaluation factors was found in the order of SCM competency (0.322), process management competency (0.314), material management competency (0.201), and purchase management competency (0.163). Among the upper classes, it was analyzed that the importance of SCM competency and process management competency was high. The final priority of evaluation factors for the development of the production management curriculum of MPE companies in the aviation logistics industry was analyzed as follows. First, supply chain performance management, which is the lower layer of SCM competency, was analyzed as the top priority factor, and the priorities of evaluation factors were derived such as facility preservation management, which is the lower layer of SCM competency, supply chain production operation, which is the lower layer of SCM competency, process quality management, which is the lower layer of SCM competency, supply chain transportation management, and supply chain supply plan, which are the lower layers of SCM competency

• Journal of Korea Port Economic Association
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• v.39 no.4
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• pp.191-203
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• 2023

This paper analyzed the overall status of the domestic freight transportation business, established SWOT analysis and strategy through existing literature research and designed an AHP model to derive priorities for each strategy. The SWOT analysis analyzed the management model of the consignment borrowers belonging to a transportation company that did not handle the supplies with the lowest satisfaction with the consignment system. The AHP model was designed by establishing a SWOT strategy through SWOT analysis. As a result of the analysis of the upper class, priorities were derived in the order of WO strategy, SO strategy, ST strategy, and WT strategy. As a result of comprehensive priorities for the development strategy of the domestic freight transportation business, WO strategy's "Improvement of cooperative relations between transportation companies and consignment owners through fair consignment contracts" was first, SO strategy's "Public promotion of the necessity of consignment systems based on high economic feasibility and reliability" was second, and ST strategy's "Proposal of policies to strengthen financial performance through the introduction of freight transport platforms" was fourth, followed by WT strategy's "Improvement of satisfaction with transport services through the introduction of freight transport platforms" and SO strategy's "Expansion of safe freight systems" in sixth, respectively.

• Journal of Korea Port Economic Association
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• v.40 no.2
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• pp.119-136
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• 2024

This study examined the impact of internal and external motivation (enjoyment, challenge, sense of accomplishment, recognition, reward) and psychological ownership of members of a land transportation company on organizational effectiveness (job satisfaction, organizational commitment), and internal and external motivation and organizational commitment. We aim to analyze the moderating effect of psychological ownership in the relationship between effectiveness. To this end, a survey was conducted targeting employees working at land transportation companies, and the results of the analysis are summarized as follows. First, among the intrinsic motivation factors of land transportation companies, challenge and sense of accomplishment had a significant impact on job satisfaction of organizational effectiveness, and enjoyment was confirmed to have an impact at a significant level. And only the sense of accomplishment had a significant effect on organizational commitment, while enjoyment and challenge had no effect. Second, recognition, an extrinsic motivator, had a significant effect on both job satisfaction and organizational commitment of organizational effectiveness, and compensation had an effect on job satisfaction but had no effect on organizational commitment. Third, psychological ownership had a significant effect on both job satisfaction and organizational commitment. Fourth, psychological ownership was found to have no moderating effect in the relationship between intrinsic motivation and organizational effectiveness, enjoyment in the relationship between challenge, job satisfaction, and organizational commitment, and to have a moderating effect in the relationship with a sense of accomplishment. Fifth, psychological ownership had a moderating effect in the relationship between extrinsic motivation and organizational effectiveness, recognition, compensation, and job satisfaction, but was found to have no moderating effect in the relationship with organizational commitment. Therefore, there is a need to improve management performance by inducing organizational commitment through job satisfaction and subsequently leading to psychological ownership.

• Journal of Navigation and Port Research
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• v.48 no.4
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• pp.249-260
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• 2024

This paper aimed to summarize research on technologies that could efficiently reduce wave-making resistance of container ships. Tto develop wave resistance reduction technology that could be applied to container ships and use it in real ship design, hull-form optimal design was performed by applying optimization algorithms, hull-form change algorithms, ship performance prediction algorithms, automation algorithms, and iterative optimal design techniques. A computer program was also developed. To properly set design variables known to be important elements in hull-form optimal design and to efficiently set lower and upper limits of design variables, a sensitivity analysis algorithm was developed and applied to hull-form optimal design. To predict the reliability and applicability of the developed computer program for real ships, hull-form optimal design was performed for a KRISO Container Ship (KCS), a container ship with various studies conducted worldwide. Hull-form optimal design was performed at Fn=0.26, the design speed of the KCS ship. Numerical analysis was performed on the hull-form of the target ship, the KCS ship, and the hull-form of the ship derived as a result of the hull-form optimal design to determine wave resistance, wave system, and wave height. The optimal ship's wave resistance was found to be reduced by 80.60% compared to the target ship. The displacement and wetted surface area were also found to be reduced by 1.54% and 1.21%, respectively.

• Journal of Navigation and Port Research
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• v.48 no.4
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• pp.321-326
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• 2024

The purpose of this study is to investigate whether Big 4 accounting firms contribute to the reduction of earnings management when auditing shipping companies. Generally, it is understood that companies audited by the Big 4 accounting firms engage in minimal earnings management and maintain high audit quality. However, these factors may vary depending on industry and firm size. As a result, this study empirically analyzes the impact of audits conducted by large accounting firms on earnings management within the shipping industry. The Big 4 accounting firms, namely PwC, KPMG, Deloitte, and EY, are the focus of this research. Discretionary accruals are employed as a proxy for earnings management, with the modified J ones model and the performance matched model used to measure discretionary accruals. The analysis, which covers shipping companies listed on KOSP I from 2001 to 2023, reveals that audits conducted by the Big 4 accounting firms do not significantly influence earnings management in the shipping industry. Unlike the general case, it is evident that audits by the Big 4 accounting firms do not play a role in reducing earnings management in shipping companies. This paper is significant as it examines the role of auditors within the shipping industry and presents findings that deviate from commonly known information. Shipping companies should take into consideration that the audit quality of the Big 4 accounting firms may not always be guaranteed when selecting an auditor. Furthermore, supervisory authorities such as the Financial Supervisory Service should engage in oversight based on an accurate understanding of the audit quality offered by the Big 4 accounting firms.

• Journal of Korea Port Economic Association
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• v.37 no.4
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• pp.127-144
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• 2021

The purpose of this study is to derive service factors based on the "Rail Statistical Yearbook" data of railroad service providers from 1990 to 2019, and to analyze the effect of the service factors on the operating profit ratio(OPR), a representative management performance variable of railroad transport service providers. In particular, it has academic significance in terms of empirical research to evaluate whether the management innovation of the KoRail has changed in line with the purpose of establishing the corporation by dividing the research period into the first period (1990-2003) and the latter (2004-2019). The contents of this study investigated previous studies on the quality of railway passenger transportation service and analyzed the contents of government presentation data related to the management performance evaluation of the KoRail. As an empirical analysis model, a research model was constructed using OPR as a dependent variable and service factor variables of infrastructure, economy, safety, connectivity, and business diversity as explanatory variables based on the operation and management activity information during the analysis period 30 years. On the results of research analysis, OPR is that the infrastructure factor is improved by structural reform or efficiency improvement. And economic factors are the fact that operating profit ratio improves by reducing costs. The safety factor did not reveal the significant explanatory power of the regression coefficient, but the sign of influence was the same as the prediction. Connectivity factor reveals a influence on differences between first period and latter, but OPR impact direction is changed from negative in before to positive in late. This is an evironment in which connectivity is actually realized in later period. On diversity factor, there is no effect of investment share in subsidiaries and government subsidies on OPR.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.7
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• pp.53-60
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• 2009

Motion estimation for H.264/AVC video CODEC is very complex and requires a huge amount of computational efforts because it uses multiple reference frames and variable block sizes. We propose the architecture of high-performance integer-pixel motion estimation circuit based on fast algorithms for multiple reference frame selection, block matching, block mode decision and motion vector estimation. We also propose the architecture of high-performance interpolation circuit for sub-pixel motion estimation. We described the RTL circuit in Verilog HDL and synthesized the gate-level circuit using 130nm standard cell library. The integer-pixel motion estimation circuit consists of 77,600 logic gates and four $32\times8\times32$-bit dual-port SRAM's. It has tile maximum operating frequency of 161MHz and can process up to 51 D1 (720$\times$480) color in go frames per second. The fractional motion estimation circuit consists of 22,478 logic gates. It has the maximum operating frequency of 200MHz and can process up to 69 1080HD (1,920$\times$1,088) color image frames per second.

• Journal of Korea Technology Innovation Society
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• v.22 no.3
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• pp.362-381
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• 2019

The purpose of this study is to examine how two factors among various affecting factors of technological innovation, i.e. sectoral system of innovation and R&D support service, were actually applied in the case of NUC Electronics. This company has achieved high level of innovation performance through change of injection port and improvement of extracting rate. This was possible because each component of sectoral system of innovation system was matched with the innovation activity. The improvement of the performance in NUC Electronics was attributable to its own innovation efforts and R&D support service of government research institute. In the process of technological innovation, the company could receive high-level services in areas such as product design and virtual experiments that companies can not solve themselves. It can be said that the role of government and public institutions to support the shortage of SMEs was important. In terms of each component of sectoral system of innovation, we found that there were many opportunities of new technology; sustainability was low; imitation was easy; appropriability was low but it has dualily; accumulation of technology was relatively high, availability of external knowledge was high. At the same time, both of the company and the network played an important role, and market conditions were very favorable. In terms of R&D support services, it is a direct effect that a great deal of time and cost savings have been achieved through virtual experiments on the material and shape of the screw. As an indirect effect, the core competence of the company has been greatly strengthened by utilizing the momentum of technology development through external support, hence the company could establish the structure of virtuous circle of innovation.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.36 no.2
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• pp.37-49
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• 2024

To date, numerous empirical formulas have been proposed through hydraulic model experiments to predict the wave breaker index, including wave height and depth of wave breaking, due to the inherent complexity of generation mechanisms. Unfortunately, research on the characteristics of wave breaking and the prediction of the wave breaker index for gravel beaches has been limited. This study aims to forecast the wave breaker index for gravel beaches using representative linear-based machine learning techniques known for their high predictive performance in regression or classification problems across various research fields. Initially, the applicability of existing empirical formulas for wave breaker indices to gravel seabeds was assessed. Various linear-based machine learning algorithms were then employed to build prediction models, aiming to overcome the limitations of existing empirical formulas in predicting wave breaker indices for gravel seabeds. Among the developed machine learning models, a new calculation formula for easily computable wave breaker indices based on the model was proposed, demonstrating high predictive performance for wave height and depth of wave breaking on gravel beaches. The study validated the predictive capabilities of the proposed wave breaker indices through hydraulic model experiments and compared them with existing empirical formulas. Despite its simplicity as a polynomial, the newly proposed empirical formula for wave breaking indices in this study exhibited exceptional predictive performance for gravel beaches.