• Journal of the Korea Safety Management & Science
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• v.14 no.4
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• pp.153-168
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• 2012

It has been recognized as an important issue to design optimally a firm's logistics network for minimizing logistics cost and maximizing customer service. It is, however, not easy to get an optimal solution by analyzing trade-off of cost factors, dynamic and interdependent characteristics in the logistics network decision making. Although there has been some developments in a system which helps decision making for logistics analysis, it is true that there is no system for enterprise-wise's on-site support and methodical logistics decision. Specially, E-biz process along with information technology has been made dramatic advance in a various industries, there has been much need for practical education closely resembles on-site work. The software developed by this study materializes efficient algorithm suggested by recent studies in key topics of logistics such as location and allocation problem, traveling salesman problem, and vehicle routing problem and transportation and distribution problem. It also supports executing a variety of experimental design and analysis in a way of the most user friendly based on Java. In the near future, we expect that it can be extended to integrated supply chain solution by adding decision making in production in addition to a decision in logistics.

• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.405-430
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• 2021

Production planning is a key part of production management of manufacturing enterprises. Since computerization began, modern production planning has been developed starting with Material Requirement Planning (MRP), and today Enterprise Resource Planning (ERP), Advanced Planning and Scheduling (APS), Supply Chain Management (SCM) has been spreading and advanced. However, in the shipbuilding field, rather than applying these general-purpose production planning methodologies, in most cases, each shipyard has developed its own production planning system. This is because the applications of general-purpose production planning methods are limited due to the order-taking industry such as shipbuilding with highly complicated construction process consisting of millions of parts per ship. This study introduces the design and development of the production planning system reflecting the production environment of heavy shipyards in Korea. Since Korean shipyards such as Hyundai, Daewoo and Samsung build more than 10 ships per year (50-70 ships in the case of large shipyards), a planning system for the mixed production with complex construction processes is required. This study draws requirements using PI/BPR (process innovation and business process reengineering) methodology to develop a production planning system for shipyards that simultaneously build several ships. Then, CBD software development methodology was applied for the design and implementation of planning system with drawn requirements. It is expected that the systematic development procedure as well as the requirements and functional elements for the development of the shipyard production planning system introduced in this study will be able to present important guidelines in the related research field of shipbuilding management.

• Journal of Wind Energy
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• v.15 no.1
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• pp.91-102
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• 2024

Rapid progress is being made in foundational technology research and engineering for the construction of floating offshore wind farms. There is active development of technology for detachable mooring systems, which have strengths in addressing maintenance issues that arise in floating offshore wind farms and enhance their economic viability. Conventional detachable mooring systems use Kenter links inserted into the middle of mooring chains, which require excessive time for retrieval by Anchor Handling Tug Supply (AHTS) vessels during detachment operations. Moreover, these operations pose risks of link damage and accidents. Therefore, there is a demand for the development of a new concept of detachable mooring systems. The proposed detachable mooring system in this study simultaneously integrates a fairlead chain stoppers (FCS) and submersible mooring pulleys (SMP), which enables all operations to be conducted on the AHTS vessel without underwater tasks. This study detailed the design and safety evaluation of the SMP, a core component of the detachable mooring system, based on the minimum breaking load (MBL) of selected mooring lines according to the capacity of the floating platform. It referenced international codes (AISC Specification for Structural Steel Buildings D5, Pin-Connected Members) for design verification and performed finite element analysis to evaluate the strength of major components in installation and operation scenarios. Additionally, procedures and techniques for evaluating the structural strength of components under uncertain boundary conditions were proposed.

• Journal of Korea Water Resources Association
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• v.41 no.1
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• pp.35-47
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• 2008

The low flow analysis is an important part in water resources engineering. Also, the results of low flow frequency analysis can be used for design of reservoir storage, water supply planning and design, waste-load allocation, and maintenance of quantity and quality of water for irrigation and wild life conservation. Especially, for identification of the uncertainty in frequency analysis, the Bayesian approach is applied and compared with conventional methodologies in at-site low flow frequency analysis. In the first manuscript, the theoretical background for the Bayesian MCMC (Bayesian Markov Chain Monte Carlo) method and Metropolis-Hasting algorithm are studied. Two types of the prior distribution, a non-data- based and a data-based prior distributions are developed and compared to perform the Bayesian MCMC method. It can be suggested that the results of a data-based prior distribution is more effective than those of a non-data-based prior distribution. The acceptance rate of the algorithm is computed to assess the effectiveness of the developed algorithm. In the second manuscript, the Bayesian MCMC method using a data-based prior distribution and MLE(Maximum Likelihood Estimation) using a quadratic approximation are performed for the at-site low flow frequency analysis.

• Korean Journal of Construction Engineering and Management
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• v.23 no.6
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• pp.30-42
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• 2022

OSC is a type of supply chain and value chain that spans the entire process of construction production (planning, design, construction, maintenance, etc.). It is a method of producing the final object by manufacturing it in a factory, transporting it to the site, installing and construction. This research as is the construction cost was compared for each case A, which applied the PC method, and case B, which applied the RC method. In the case of applying the PC method (excluding the PC design cost), compared to the case where only the RC method was applied, the frame construction cost per unit quantity (m³) increased by about 70% (50% based on the total RC construction type). Of the total frame construction cost of PC method application, PC accounted for 90.2%, 'PC manufacturing cost' 54.8%, 'PC assembly cost' 28.5%, and 'transportation cost' accounted for 6.89%. Also a decision-making framework that can consider both costs and benefits was established. In the case of benefits, the construction period, defect repair, disaster occurrence, energy efficiency, noise/dust/waste, and greenhouse gas emission indicators reflecting OSC technical advantages were presented. It can contribute to providing a basis for helping decision-making on the introduction of PC apartment houses using OSC.

• KIPS Transactions on Software and Data Engineering
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• v.9 no.12
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• pp.387-402
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• 2020

Conventional automotive development has mainly focused on ensuring correctness and safety and security has been relatively neglected. However, as the number of automotive hacking cases has increased due to the increased Internet connectivity of automobiles, international organizations such as the United Nations Economic Commission for Europe(UNECE) are preparing cybersecurity regulations to ensure security for automotive development. As with other IT products, automotive cybersecurity regulation also emphasize the concept of "Security by Design", which considers security from the beginning of development. In particular, since automotive development has a long lifecycle and complex supply chain, it is very difficult to change the architecture after development, and thus Security by Design is much more important than existing IT products. The problem, however, is that no specific methodology for Security by Design has been proposed on automotive development process. This paper, therefore, proposes a specific methodology for Security by Design on Automotive development. Through this methodology, automotive manufacturers can simultaneously consider aspects of functional safety, and security in automotive development process, and will also be able to respond to the upcoming certification of UNECE automotive cybersecurity regulations.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.3
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• pp.170-179
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• 2016

In this paper we have tackled the outstanding inventory planning problems over new product launching period in a more holistic manner by addressing first the definition of efficient business rules to effectively control and reduce the inventory risks followed by the rigorous explanations on the implementation guide on suggested inventory planning rules. It is not unusual for many companies in the consumer electronics market to make a great effort to reduce the time to launch a new product because the ability to bring out higher performing products in such a short time period greatly increases the probability for them to remain competitive in the high tech market. Among so many newly developed products, those products with new features and technologies appeal to many potential customers while products which fail to win customers by design and prices rapidly disappear in the market. To adapt to this business environment, those companies have been trying to find the answer to minimize the inventory of old products so they can move to next generation products quickly with less obsolete material. In the experimental implementation of our rule-based inventory planning, Company 'S' reduced the inventory cost for the outgoing products as low as 49% of its peak level of its preceding product version in just 5 month after the adoption of rule-based inventory planning process and system. This paper concluded the subject with a suggestion that the best performance of rule-based inventory planning is guaranteed not from one-time campaign of process improvement along with system development but the decision maker's continuing support and attention even without seeing any upcoming business crisis.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.7
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• pp.731-738
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• 2007

Recently UHF RFID system has drawn a great deal of attention because of its potential to revolutionize supply chain management. In this article, RFID reader-to-reader interference is analyzed in terms of interrogation range. For evaluating RFID interference quantitatively, the new figure-of-merit, IRRR, is defined. In order to show the usefulness of IRRR, calculated IRRR is verified by measurement using two RFID readers and a tag in multiple-reader environment. IRRR can be referred to an important design parameter to analyze more complex interfering problems in actual RFID system deployments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.12
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• pp.1079-1085
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• 2013

Due to the limited power supply resources, it is essential that the minimization of algorithmic operation and the reduction of the hardware logical-resources in the design of the satellite transponder. It is also required that the transponder process the signals of various bandwidth efficiently, that is suitble for the SDR-based implementation. This paper proposes a variable rate down sampler which can provide variable bandwidth and data rate for carrier, ranging and sub-band command signals respectively. The proposed down sampler can provide multiple $2^M$ decimated outputs from a single half band filter with recursive arithmetic architecture, which can minimize the hardware resources as well as the arithmetic operations. The algorithm for hardware implementation as well as the analysis for the passband flatness and aliasing is presented and varified by the FPGA implementation.

• Journal of Distribution Science
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• v.15 no.1
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• pp.123-130
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• 2017

Purpose - This research aims to examine the effect of e-business adoption on firm's growth and profitability in the distribution industry. The value added from the distribution industry acts as the cost of other industries. As the distribution industry develops, its stage becomes shorter and the distribution margin becomes smaller. Therefore, e-business is expected to have a different effect on the distribution industry than other industries. Research design, data and methodology - The previous research generally used e-business adoption as an independent variable and firm's performance as a dependent variable. This study elaborated the model using a dynamic panel model that includes the performance variable of the previous year as an independent variable. By employing system GMM (Generalized Method of Moments), the endogeneity problem in the dynamic panel model can be solved. For the analysis, I extracted the distribution companies as the raw data in the National Statistical Office's Business Activity Survey over the period 2006 to 2012. Results - The growth rate of firms adopting e-business was 0.299%p higher than that of the non-adopter. However, only ERP (Enterprise Resource Planning), KMS (Knowledge Management System) and SCM (Supply Chain Management) contributed positively to the growth rate. In the case of profitability, it was 0.04%p higher than the distribution companies that did not adopt e-business. ERP and LMS (Learning Management System) improve profitability, while SCM reduces profitability. Consequently, while ERP improves both growth and profitability, SCM improves growth but reduces profitability. In addition, KMS improves firm's growth only, and LMS does only profitability, showing that each e-business has a differentiated effect. Conclusions - Since the distribution industry has different characteristics from manufacturing and other service industries, the introduction of e-business may not guarantee the growth and profitability of distribution companies. Careful introduction considering the characteristics of the distribution industry is required. In particular, it is necessary to select an e-business meeting the characteristics and needs of a distribution company, and thereafter, it is required for the company's own efforts to internalize it within the system.