• Journal of the Korean Society for Aviation and Aeronautics
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• v.22 no.3
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• pp.8-14
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• 2014

Arrival management is a tool which provides efficient flow of traffic and reduces ATC workload by determining aircraft's sequence and schedules while they are in cruise phase. As a decision support tool, arrival management should advise on air traffic control service based on the understanding of human factor of its user, air traffic controller. This paper proposed a prediction model for air traffic controller sequencing strategy by analyzing the historical trajectory data. Statistical analysis is used to find how air traffic controller decides the sequence of aircraft based on the speed difference and the airspace entering time difference of aircraft. Logistic regression was applied for the proposed model and its performance was demonstrated through the comparison of the real operational data.

• Journal of Power Electronics
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• v.7 no.3
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• pp.203-212
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• 2007

In this paper, a proposed approach to improve the power factor of three-phase rectifiers and to stabilize the output voltage against load change is presented. The elements of the given control strategy are small size, low cost, high performance, and simplicity. The proposed control strategy of switches is based on a prototype of three bi-directional switched consisting of four diodes and one IGBT. A control technique and operational procedure are also developed, both theoretically and experimentally. The experimental results clearly verify the theoretical analysis from the prototype connected to grid unity.

• Journal of Power Electronics
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• v.19 no.3
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• pp.803-814
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• 2019

This paper proposes a three-phase current balancing strategy in a power transmission system employing distributed static series compensators (DSSCs). With the proposed variable quadrature voltage injection method, the DSSC emulates either an inductive or a capacitive impedance into the transmission line, and the magnitudes of the phase currents are balanced. Hence, the phase imbalances in the power transmission system are significantly reduced. As a result, the power transfer capability of the transmission lines can be improved. The operational principle of the DSSCs, the hardware structure and the control algorithm are described in detail. Finally, the theoretical analyses and the proposed strategy are experimentally verified through a scaled down transmission system with DSSC prototypes.

• Maritime Security
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• v.1 no.1
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• pp.93-117
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• 2020

Four cargo ships were ambushed by bombs in 2019 while navigating in the Strait of Hormuz. It was not clear who attacked those ships, however, many nations including the United States argued that it was Iran due to several reasons. The United States established the maritime collective defense system named International Maritime Security Construct (IMSC) in order to protect the maritime security in the Strait of Hormuz, without disclosure against whom it is aimed. Persian, who uses the Persian language unlike other countries in the Middle East, is the major ethnic group in Iran, and most of them believe Shi'ah Islam while most of the Arabs in the Gulf countries adhere to Sunni Islam. It seems that historic and religious motives caused the bipolar system in the Middle East, however, it is plausible to analyze the system of international affairs in the Middle East via defensive or structural realism. Iran has attempted to maintain its hegemony in the region by supporting Shi'ah muslims in the neighboring countries as well as in the world by using military and economic means. In this context, Iran's maritime strategy is to maintain its maritime hegemony on the Persian Gulf via countering threats and cooperating with friendly navies by using the Islamic Republic of Iran Navy(IRIN) and the Islamic Revolutionary Guard Corps Navy(IRGCN). IRIN acts like other navies in the world: protecting national interest at sea, expending its operational areas to the outer seas, and enhancing cooperation with other navies. Meanwhile, IRGCN plays a role as an asymmetric force at sea. It is composed of small and fast asymmetric assets, which can ambush ships fast and furious. Considering the poor study for Iran's maritime strategy in Korea, analyzing the strategy is meaningful for the Republic of Korea Navy, which has operated the Cheonghae Unit for more than ten years since it has extended its operational area over the Strait of Hormuz. In order not to be drawn into the conflict in the Strait, research on the maritime strategy of Iran and other countries in the Middle East should be started.

• Journal of Korean Society for Quality Management
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• v.38 no.1
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• pp.10-19
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• 2010

The competitive strategies of the Korean manufacturing companies have changed from the "cost leadership" strategy in the early developing stage since 1960's to the "stuck in the middle" position since 1990's in the face of emerging new cost leaders as the Chinese companies. The data on the strategic contents of the Korean manufacturing companies show that their strategies are seeking the value innovation through not only quality improvement but also cost reduction altogether rather than selecting one on the trade-off relation between the both competitive dimensions. Their strategic actions seem to be seeking the operational efficiencies through all the value chain activities rather than the strategic effectiveness by selecting and focusing on the specific competitive dimension, which is considered as a typical strategic approach. Their strategy seems to be non-strategic in the general sense. But their non-strategically looking behaviors can be reasonable enough for their sandwiched competitive position between the global quality leaders and following cost leaders. This paper explains why their strategies can be right through the theoretical explanations by using the quality-price elasticity approaches for the consumer behaviors. We can call their strategic activities as the value innovation strategy.

• Asia-Pacific Journal of Business
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• v.9 no.2
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• pp.15-37
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• 2018

The purpose of this paper was to explain on the conceptualisation of the Halal Orientation strategy (HOS) based on operation strategy perspective. The four variables constitute in HOS are staffing, materials, production process and storage together with transportation. By focusing on HOS, the manufacturers reinforce improvement in quality, cost control, time and flexibility of the production Halal food industry in Malaysia which is the performance objective of market competitiveness in Malaysia context. A self-administered questionnaire was designed and used to assess the significant of HOS that lead to improve quality, cost control, reduction in time and the flexibility among Halal food manufacturers in Malaysia. From a total of 443 Halal food manufacturers were involved in this study, only 137 respondents are usable for this research. The study showed significant results for the manufacturers to focus in Halal Orientation strategy (HOS) which have positive impacts on quality, cost control, time and flexibility. This research aimed to measure the HOS among food firms in Malaysia and to determine HOS in relation with the performance objective of operational outcomes.

• Journal of Elementary Mathematics Education in Korea
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• v.13 no.1
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• pp.51-74
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• 2009

The purpose of this study is to search for various strategies that could self-regulated learning within cyber home study efficiently, to operate the cyber home study based on such strategies, to manage and support students' learning and to investigate what effects it would have on the ability of self-regulated learning and attitude. In this study, an operational strategy for cyber home study according to the compositional elements of self-regulated learning based on prior studies. Then, the study developed the learning contents of cyber home study and operated cyber home study according to the operational strategy. From the results of the analysis obtained in this study, the following conclusions can be drawn as follows. First, A learner's self-regulated learning capability is able to be improved by self-regulated leaning strategies. Cyber home study that would enable students to implement the leaning on their own through learning contents and operating strategies corresponding to them was the environment that could help their self-regulated learning. Second, in order to find out students' satisfaction for the application of cyber home study, the study compared the survey of cyber home study with the frequency and percentage by each question and the mean value of technical statistics. Cyber home study let students have positive recognition on mathematical learning, and especially as shown in the results of the interview, it was helpful to improve students' interest and confidence as well as their mathematical learning.

• Journal of Korea Society of Industrial Information Systems
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• v.27 no.1
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• pp.93-109
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• 2022

Today, digital transformation in providing service value to companies that combine service and technology is becoming a necessity. In the transition period of digital transformation, various factors such as data, artificial intelligence technology, and partnerships can become competitive factors. In particular, digital transformation, which combines information and services with customers, creates a new business model that changes the entire industry and is presented as core competitiveness that creates customer value. From these aspects, the purpose of this case study is to derive competitive advantages on digital transformation using the case of company S. First, the study analyzes the same type of industry based on the case of app service. Second, this study presents preference factors in the operational process to enhance competitiveness by expanding user participation in accommodation reservation services. In addition, the customer service value model provides through the analysis of the five competitive factors in the operational process. This study elaborates the implications of the customer service value creation model in terms of new opportunities and challenges in digital transformation as a new customer service strategy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.269-275
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• 2020

RAM of elements to support weapon systems is conducted at the initial development phase and standard is suggested to accomplish strategy requirement performance from a design spec. Operational availability is a key point of the military's ability to ensure combat readiness and to win the battle. In the weapon system development phase, operational availability is used as a development standard. The military provides ALDT, operation and standby time, which are elements of operational availability. ALDT is a key element of operational availability that must be maintained for combat readiness, as it depends on the aging of a weapon system, maintenance policies and geographical conditions. Operational Availability to be set at the development phase has many differences from the operational availability that is analyzed in the actual operational phase because ALDT is applied as a simple assumption. In the paper, we analyzed ALDT applying the decision tree method through failure data acquired from initial operation. Through this study, we have devised the optimal ALDT setting method to achieve operational availability about operation when the weapons system is unstable.

• Aerospace Engineering and Technology
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• v.6 no.1
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• pp.92-96
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• 2007

The conventional commands & telemetry system of Korean low-earth orbiting satellites has certain limitations in accommodating various missions. As the payload becomes complex, it requires very complicated operational concepts in terms of commands and telemetry. With the current design, commands and telemetry formats have to be rebuilt whenever new payloads or operation concepts are involved, and many constraints in operation shall be produced due to the lacks of its flexibility. In this paper, a new strategy for commands & telemetry development partially derived from PUS (Packet Utilization Standard) of European Space Agency, which provides enhanced features for the accommodation of payloads & operational requirements, is presented.