• Journal of Korea Port Economic Association
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• v.40 no.2
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• pp.175-189
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• 2024

Following the introduction of containerized sea transportation, the size of container ships has progressively increased. While the primary objective of this enlargement is to achieve economies of scale, it significantly affects the operational environment of ports where these ships dock, raising concerns about the validity of efficiency gains from ultra large container vessels from a port operational perspective. This study evaluates the efficiency of various ship sizes from January to December 2022, utilizing internal data from the container terminals A and B located in the Busan New Port. The analysis encompasses ships affiliated with The Alliance at Container Terminal A and those associated with 2M at Container Terminal B. Key input variables considered for the study include ship size (TEU), total berth time, and loading/unloading time, with cargo handling performance serving as the only output variable. The findings indicate that larger ship sizes exhibit higher efficiency compared to smaller container ships.

• Geophysics and Geophysical Exploration
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• v.27 no.3
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• pp.171-180
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• 2024

The processing of seismic data involves analyzing earthquake wave data to understand the internal structure and characteristics of the Earth, which requires high computational power. Recently, machine learning (ML) techniques have been introduced to address these challenges and have been utilized in various tasks such as noise reduction and velocity model construction. However, most studies have focused on specific seismic data processing tasks, limiting the full utilization of similar features and structures inherent in the datasets. In this study, we compared the efficacy of using receiver-wise time-series data ("receiver array") and synchronized receiver signals ("time array") from shotgathers for pretraining a Bidirectional Encoder Representations from Transformers (BERT) model. To this end, shotgather data generated from a synthetic model containing faults was used to perform noise reduction, velocity prediction, and fault detection tasks. In the task of random noise reduction, both the receiver and time arrays showed good performance. However, for tasks requiring the identification of spatial distributions, such as velocity estimation and fault detection, the results from the time array were superior.

• Journal of the Korea Society of Computer and Information
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• v.29 no.9
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• pp.25-37
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• 2024

This study proposes a novel automation system that integrates Optical Character Recognition (OCR) and Retrieval-Augmented Generation (RAG) technologies to enhance the efficiency of the ESG (Environmental, Social, and Governance) document review process. The proposed system improves text recognition accuracy by applying an ensemble model-based image preprocessing algorithm and hybrid information extraction models in the OCR process. Additionally, the RAG pipeline optimizes information retrieval and answer generation reliability through the implementation of layout analysis algorithms, re-ranking algorithms, and ensemble retrievers. The system's performance was evaluated using certificate images from online portals and corporate internal regulations obtained from various sources, such as the company's websites. The results demonstrated an accuracy of 93.8% for certification reviews and 92.2% for company regulations reviews, indicating that the proposed system effectively supports human evaluators in the ESG assessment process.

• Design & Manufacturing
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• v.18 no.3
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• pp.15-21
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• 2024

This study investigates the causes of wrinkle defects in PA12-insulated busbars used in electric vehicles and proposes an improvement method to address these issues. Busbars, essential components for efficient current transmission in electric vehicle battery modules, require complex three-dimensional bending to optimize internal layouts. For this study, oxygen-free copper busbars with a 0.8 mm PA12 insulation coating were subjected to three types of bending tests: flat bending, edge bending, and torsional bending. Experimental results showed that wrinkle defects only occurred during edge bending, while flat and torsional bending modes exhibited no significant issues. Cross-sectional analysis revealed that the PA12 insulation layer's thickness was uneven, with thinner sections on flat areas and thicker accumulation at the comers. This uneven distribution led to poor adhesion between the insulation and copper layers, resulting in the formation of wrinkles, particularly in areas with air gaps ranging from 75 to 250 ㎛. To further analyze the issue, finite element analysis (FEA) of the bending process was performed under adhesive and non-adhesive conditions. The results confirmed that wrinkles formed when the adhesion between the copper and PA12 coating was insufficient. Improved adhesion conditions, achieved through a heat treatment process at 120℃ for 2 hours, significantly reduced the occurrence of wrinkles during edge bending. This study demonstrates that optimizing the adhesion between the insulation coating and the copper busbar, through controlled heat treatment, can prevent wrinkle defects. The findings provide a pathway for enhancing the durability and performance of insulated busbars in electric vehicle applications.

• Radiation Oncology Journal
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• v.17 no.4
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• pp.281-286
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• 1999

Purpose : Brain metastases are the most frequent metastatic neurologic complication of systemic cancer. Even if the prognosis of brain metastases is grave, with available treatments, most patients experience effective palliation of neurologic symptoms and meaningful extension of life. We evaluated the clinical features and prognostic factors of the patients who were diagnosed as solid tumors with brain metastasis and received radiotherapy for brain metastases. Materials and Methods: Between January 1987 and January 1998, 71 patients with brain metastases from solid malignancy were included. We reviewed neurologic symptoms and signs of patients and evaluated improvememt of neurologic symptoms and signs. Survival durations after brain metastasis were ana lysed according to several factors such as age, performance status, primary malignancies, the pre-sence of brain metastasis at initial diagnosis of primary tumor, multiplicity of brain metastass, the presence of metastases other than brain, and treatment method. Results: Frequent symptoms associated with brain metastasis were headache (47.9$\%$), motor weakness (40.8$\%$), nausea and vomiting (19.7$\%$) and mental change (19.7%). Palliation of these symptoms was accomplished in 64.9$\%$ of cases. The overall median survival time was 16 weeks and 1- and 2-year survival rates were 15.0$\%$ and 5.1$\%$ respectively. Patients without extracranial metastases (n=27) had longer median survival than patients with extracranial metastases (33 weeks vs 10 weeks, p=0.0018). In patients with single brain metastasis (n=37), the median survival time was longer in patients treated with surgery plus radiotherapy than in patients treated with radiotherapy alone (40 weeks vs 16 weeks, p=0.0438). Conclusion: Patients who has brain metastases only constitute a prognostically favorable group and they may be benefited from radiotherapy and surgery if indicated.

• Radiation Oncology Journal
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• v.20 no.2
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• pp.123-129
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• 2002

Purpose : The purpose of this study 띤as to determine the potential role of three-dimensional conformal radiotherapy (3D-CRT) in the treatment of primary unresectable hepatocellular carcinoma. The preliminary results on the efficacy and the toxicity of 3D-CRT are reported. Materials and Methods : Seventeen patients were enrolled in this study, which was conducted prospectively from January 1995 to June 1997. The exclusion criteria included the presence of extrahepatic metastasis, liver cirrhosis of Child-Pugh classification C, tumors occupying more than two thirds of the entire liver, and a performance status of more than 3 on the ECOG scale. Two patients were treated with radiotherapy only while the remaining 15 were treated with combined transcatheter arterial chemoembolization. Radiotherapy was given to the field including the tumor plus a 1.5 cm margin using a 3D-CRT technique. The radiation dose ranged from $36\~60\;Gy$ (median; 59.4 Gy). Tumor response was based on a radiological examination such as the CT scan, MR imaging, and hepatic artery angiography at $4\~8$ weeks following the completion of treatment. The acute and subacute toxicities were monitored. Results : An objective response was observed in 11 out of 17 patients, giving a response rate of $64.7\%$. The actuarial survival rate at 2 years was $21.2\%$ from the start of radiotherapy (median survival; 19 months). Six patients developed a distant metastasis consisting of a lung metastasis in 5 patients and bone metastasis in one. The complications related to 30-CRT were gastro-duodenitis $(\geq\;grade\;2)$ in 2 patients. There were no treatment related deaths and radiation induced hepatitis. Conclusion : The preliminary results show that 3D-CRT is a reliable and effective treatment modality for primary unresectable hepatocellular carcinoma compared to other conventional modalities. Further studies to evaluate the definitive role of the 3D-CRT technique in the treatment of primary unresectable hepatocellular carcinoma are needed.

• Journal of Hospice and Palliative Care
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• v.22 no.4
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• pp.198-206
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• 2019

Purpose: The Act on Hospice and Palliative Care and Decisions on Life-sustaining Treatment for Patients at the End of Life was enacted in 2016 and has taken effect since 2018 February. The content of this act was based on Physician Orders for Life-Sustaining Treatment (POLST) in the United States and we modified it for terminal cancer patients registering hospice. The object of this study is to investigate preference and implementation rate for modified Korean POLST (MMK-POLST) items in hospice ward. Methods: From February 1, 2017 to April 30, 2019, medical records regarding MMK-POLST were retrospectively analyzed for all patients hospitalized in the hospice ward of Gyeongsang National University Hospital. Results: Of the eligible 387 total cohorts, 295 patients filled out MK-POLST. MK-POLST has been completed in 133 cases (44.1%) by the patient themselves, 84 cases (28.5%) by the spouse, and 75 cases (25.4%) by their children, respectively. While only 13 (4.4%) out of 295 MK-POLST completed patients refused the parenteral nutrition and 5 patients (1.7%) for palliative sedation, the absolute majority of 288 (97.6%) patients did not want cardiopulmonary resuscitation (CPR) and ventilators and 226 people (76.9%) for pressor medications. Kappa values for the matched strength of MK-POLST implementation were poor for all items except CPR, ventilators and palliative sedation. Conclusion: Hospice patients refused to conduct cardiopulmonary resuscitation, ventilators and pressor agents. In contrast, antibiotics, parenteral nutrition and palliative sedation were favored in the majority of patients.

• Radiation Oncology Journal
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• v.16 no.1
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• pp.7-16
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• 1998

Purpose : To evaluate survival rate and prognostic factors affecting survival of patients with esophageal cancer treated with concurrent chemoradiation. Materials and Methods : Eligibility included biopsy proven invasive carcinoma of the cervical or thoracic esophagus, confined to esophagus and mediastinum with or without regional lymph node and supraclavicular lymph node, and ECOG Performance status $H_0-H_2$. Patients received radiation therapy with 5940cGy over 7 weeks and chemotherapy, consisted of 5-FU(1000 $mg/m^2/day$ in continuous infusion for 5 days, days 1 to 5 and days 29 to 33) and mitomycin C($8mg/m^2$ intravenous bolus at day 1). After concurrent chemoradiation, maintenance chemotherapy was followed with 5-FU(1000 $mg/m^2/day$ in continuous infusion for 5 days at 9th, 13th, and 17th weeks) and cisplatin($80mg/m^2$ intravenous bolus at the first day of each cycle). Results : From November 1989 to November 1995, 44 patients were entered in this study. After treatment, complete response rate and partial response rate were $59\%$ and $41\%$. Overall 1, 2, and 5-year survivals were $59\%$, $38\%$, and $9.6\%$(median 17 months), Prognostic factors affecting survival were response to treatment and T-stage. Among 26 complete responders, there were 6 local recurrences, 3 distant recurrences, 1 local and distant recurrence, and 2 unknown site recurrences Acute and chronic complication rates with grade 3 or more were $20\%$ and $13.0\%$ and there was no treatment-related mortality. Conclusion : Concurrent chemoradiation, compared with historical control groups that treated with radiation alone, improved median survival and did not significantly increase treatment-related complications. Complete responders had longer survival duration than partial responders. Predominant failure pattern was local failure. So, efforts to improve local control should be proposed.

• Journal of Korea Port Economic Association
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• v.40 no.1
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• pp.151-163
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• 2024

This study sought to confirm the impact of analytical methods and behavioral economic theory factors on decision-making when making chartering decisions in the dry bulk shipping market. This study on chartering decision-making model was began to verify why shipping companies do not make rational decision-making and behavior based on analytical methods such as freight prediction and process of alternative selection in the same market situation. To understand the chartering decision-making model, it is necessary to study the impact of behavioral economic theory such as heuristics, loss aversion, and herding behavior on chartering decision-making. Through AHP analysis, the importance of the method factors relied upon in chartering decision-making. The dependence of the top factors in chartering decision-making was in the following order: market factors, heuristics, internal factors, herding behavior, and loss aversion. Market factors, heuristics, and internal factors. As for detailed factors, spot freight index and empirical intuition were confirmed as the most important factors relied on when making decisions. It was confirmed that empirical intuition is more important than internal analysis, which is an analytical method. This study can be said to be meaningful in that it academically researched and proved the bounded rationality of humans, which cannot be fully rational, and sometimes relies on experience or psychological tendencies, by applying it to the chartering decision-making model in the dry bulk shipping market. It also suggests that in the dry bulk shipping market, which is uncertain and has a high risk of loss due to decision-making, the experience and insight of decision makers have a very important impact on the performance and business profits of the operation part of shipping companies. Even though chartering are a decision-making field that requires judgment and intuition based on heuristics, decision-makers need to be aware of this decision-making model in order to reduce repeated mistakes of deciding contrary to market situation. It also suggests that there is a need to internally research analytical methods and procedures that can complement heuristics such as empirical intuition.

• Information Systems Review
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• v.15 no.3
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• pp.39-69
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• 2013

Business value of information technology has been the biggest interest of all such as practitioners and scholars for decades. Information technology is considered as the driving force or success factor of firm agility. The general assumption is that organizations making considerable efforts in IT investment are more agile than the organizations that are not. However, IT that should help the strategies of the firm that can hinder business or impede agility of the firm occasionally. In other words, it is still unknown if IT helps the agility of the firm or bothers it. Therefore, we note that contrary aspects of IT such as promotion and hindrance of firm agility have been observed frequently and theorize the relationships between them. In other words, we propose a rationale that firms should need to develop superior firm-wide IT capability to manage IT resources successfully in order to realize agility. Thus, this paper theorizes two IT capabilities, including technical IT capability and managerial IT capability as key factors impacting firm agility and firm performance. Further, we operationalize firm agility into two sub-types, including operational adjustment agility and market capitalizing agility. The data from 171 firms was analyzed using PLS approach. The results showed that technical IT capability has positive impact on firm agility and managerial IT capability had positive moderating effects between technical IT capability and firm agility. In addition, it was identified that top management championship positively moderates between agility and firm performance. Finally, it was indicated that firm agility was a very important causal variable of firm performance. Our study provides more exquisite and practical empirical evidences in the relationship between IT capability and firm agility by proposing applicable solution although IT has some contradicting effects on firm agility. Our findings suggest many useful implications to agility related researches in relatively primitive stage and working level officers in organizations.