• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.8
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• pp.1483-1490
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• 2009

This parer is presented multiple path-planning of unmanned autonomous forklift using modified genetic algorithm and fuzzy inference system. There are a task-level feedback method and a method that path is dynamically replaned in realtime while the autonomous vehicles are moving by means of an optimal algorithm for existing multiple path-planning. However, such methods cause malfunctions and inefficiency in the sense of time and energy, and path-planning should be dynamically replanned in realtime. To solve these problems, we propose multiple path-planning using modified genetic algorithm and fuzzy inference system and show the performance with autonomous vehicles. For experiment, we designed and built two autonomous mobile vehicles that equipped with the same driving control part used in actual autonomous forklift, and test the proposed multiple path-planning algorithm. Experimental result that actual autonomous mobile vehicle, we verified that fast optimized path-planning and efficient collision avoidance are possible.

• Proceedings of KOSOMES biannual meeting
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• 2003.11a
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• pp.7-11
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• 2003

Ship is being operated under a highly dynamic environments and many factors are related with ship's collision and those factors are interacting. So, an analysis on the ship's collision causes is very important to prepare countermeasures which will ensure the safe navigation. And the analysis confirmed that ship's collision is occurred most frequently and the cause is closely related with human factor. The main purpose of this study is to build a model of human factors in ship's collision cause using SD(System Dynamics} approach and to measure a effect which is risk control countermeasures of ship's collision. To achieve this aim, the structure analysis on the causes of ship's collision using FSM are performed, and the structure was changed by quantitative, qualitative factors and their feedback loops in casual map. This model was performed over 20 years(1993-2012) in a standard simulation model and 8 policy simulation models.

• Proceedings of KOSOMES biannual meeting
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• 2004.05b
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• pp.29-34
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• 2004

Ship is bring operated under a highly dynamic environments and many factors are related whit marine accident and those factors are interacting. An analysis on the marine accident is very important to prepare countermeasures which will ensure the safe navigation This paper aims to build a model of the rouses and improved policy for marine accident using SD(System Dynamics) approach and to measure a effect which is risk control countermeasures of marine accident The methodology of this paper is to perform the causes and improved policy for marine accident using Brainstorming method, and was to changed by quantitutive, qualitative factors and their feedback loops in casual map. This model was performed over 23 years($1997\~2020$) in a standard simulation model and 4 policy simulation models.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.2
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• pp.259-265
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• 2012

Recently, many research works are focusing on DVC (Distributed Video Coding) system for low complexity encoder. Most DVC systems need feedback channel for parity bit control to achieve the good RD performances, however, this causes the system to have high decoding latency and is considered as one of the most critical problems for real implementation. In order to overcome this problem, this paper proposes an effective distributed video decoding method using adaptive LDPCA frame-based parity bit request estimation. The proposed method applies for the pixel-domain Wyner-Ziv system and exploits the statistical characteristics between adjacent LDPCA frames to estimate adaptively the parity bit request. Through computer simulations, it is shown that the proposed method achieves about 80% of latency reduction compared to the conventional no-estimation DVC system.

• Journal of Korean Society of Rural Planning
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• v.29 no.4
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• pp.211-219
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• 2023

In this study, the importance of each design element was analyzed by surveying experts in the development of Agro-Healing Virtual Reality Therapy System. It was found that the results of experts content importance were consistent with the results of consumer preferences in previous studies, such as psychological and emotional stability as the main effect the importance of sight and hearing, a relatively short time of 30 minutes or less, a low price of 5,000 won or less, technical factors that can satisfy the five senses, and various contents. When the spatial elements of the Agro-Healing Virtual Reality Therapy System were categorized into three major categories: elements and equipment, lines and paths, and sites and spaces, 'flowers', 'playgrounds', 'paths', 'sidewalks', 'rest areas' and 'gardens' were found to be highly important. Among the components of Agro-Healing Virtual Reality Therapy System, the usability was divided into eight major categories, including searchability, attractiveness, cognition, error handling, control, consistency, convenience, and feedback, and the importance was analyzed for each component. The significance of this study is that it suggests the design direction of virtual healing farm systems and provides effective information that can be used in the development of related systems in the future.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.4
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• pp.43-61
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• 2017

The wetlands are facing environmental changes such as desiccation that occurs with the passage of time and reduced ecosystem services from wetlands in the city. In order to maintain the ecosystem services provided by wetlands in urban areas, a system thinking about the trade-off phenomenon of ecosystem services occurring as the wetlands undergo environmental changes is needed. Therefore, the purpose of this study is to develop strategies for wetland design using system thinking approach to enhance the resilience of ecosystem services degraded by the desiccation of wetlands and other disturbances. The objectives of this study include the system boundary and variables. Second, analyzing the dynamics of wetland design strategy. Third, it analyzes the trade-off phenomenon of ecosystem services in terms of the hydrology, hydric soil, and plants strategies to mitigate these effects. Fourth, wetland basic design to improve the resilience of ecosystem services. A wetland in Abuk-Mountain Neighborhood Park, Miryang-si, Gyeongsangnam-do, has been selected as a case study. Causal loop diagrams(CLDs) are used to analyze feedback in the wetland regime. In summary, hydrology, hydric soil, and plants is suggested as system boundaries to design plan. Design strategies for the wetland focused on robustness, redundancy, rapidity, and resourcefulness as a result of CLD analysis are first proposed in order to effectively maintain the wetland regime over the long term. Secondly, in a section related to hydrology, the CLD results show the trade-offs between provisioning-cultural services and regulating services. In order to control these services, a "water cycling system" has been implemented due to its strength in terms of robustness. The CLDs for hydric soil showed the trade-offs between regulating services and supporting services. An "installation of storm drainage for maintaining water levels" was selected due to the strength offered in terms of redundancy and rapidity. The CLDs for plants showed the trade-offs between provisioning - cultural services and regulating services. In order to control the strategic points, the "planting of indigenous vegetation" was suggested given the strength in terms of redundancy. In this study, a wetland design method is proposed that can improve the resilience of wetland ecosystem services by analyzing the dynamics overtime. The results of this research can theoretically be applied to help restore ecosystem services in wetlands using ecological landscape design. In addition, this study will contribute to reducing maintenance costs by improving wetland resilience.

• Management Science and Financial Engineering
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• v.8 no.1
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• pp.21-38
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• 2002

Rapid advances in information technology(IT) and telecommunication systems impact the number and quality of decision-making in organizations. Specifically, middle mangers must posses or develop the creativity necessary for survival in a constantly changing and volatile business environment. While tradition and conventional wisdom tell us that a middle managers role centers on control and monitoring, todays competitive arena has spun out a new managerial requirement developing and maintaining an innovative attitude. Problematically, most previous research has focused on the issue of changing decision authority (i. e. centralization/decentralization). Moreover, much previous research has also largely ignored environmental changes exposing new roles that middle managers have assumed. This study explores the means of identifying middle managerial roles, managerial possibilities involving the growing popularity of open systems through electronic brainstorming, and an adaptation and development of Diffusion Theory and attempt to counter criticism leveled at the theory's inability to provide an adequate explanation for diffusion of complex organizational technology. This paper develops three ideas: 1) Introducing the 'Chasing Curve' as a theoretical background. 2) Suggesting a new methodology using electronic brainstorming for analyzing the gap between Knowing (the perceived importance of middle managers' roles) and Doing (the degree of current status of middle managers' roles), which we term the 'Spiral Gap Analysis Model'. 3) Identifying a feedback system for minimizing the Knowing - Doing gap, aimed at development of IT strategic priority decision support, which we call this the 'Star Process'.

• Journal of Power Electronics
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• v.14 no.1
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• pp.183-193
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• 2014

Due to the requirements for high reliability and accuracy, safety issues for airbag ignition systems need to be studied. In this paper, a high-voltage piezoelectric converter is designed to improve these requirements in airbag ignition systems. The proposed converter includes an inverter drive circuit, a Rosen piezoelectric transformer (PZT), an output circuit and a feedback control circuit. The key components of the high-voltage piezoelectric transformer are analyzed in detail. In addition, the proposed converter system is simulated and implemented for testing. The experimental results show that when the power supply is turned on, the charging time is less than 800ms. Furthermore, the output voltage of this converter can be kept between 2.9kV and 3.1kV, under high-efficiency constant current charging mode and zero-voltage switching conditions.

• BMB Reports
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• v.49 no.11
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• pp.587-589
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• 2016

The circadian clock system enables organisms to anticipate the rhythmic environmental changes and to manifest behavior and physiology at advantageous times of the day. Transcriptional/translational feedback loop (TTFL) is the basic feature of the eukaryotic circadian clock and is based on the rhythmic association of circadian transcriptional activator and repressor. In Drosophila, repression of dCLOCK/CYCLE (dCLK/CYC) mediated transcription by PERIOD (PER) is critical for inducing circadian rhythms of gene expression. Pacemaker neurons in the brain control specific circadian behaviors upon environmental timing cues such as light and temperature cycle. We show that amino acids 657-707 of dCLK are important for the transcriptional activation and the association with PER both in vitro and in vivo. Flies expressing dCLK lacking AA657-707 in $Clk^{out}$ genetic background, homologous to the mouse Clock allele where exon 19 region is deleted, display pacemaker-neuron-dependent perturbation of the molecular clockwork. The molecular rhythms in light-cycle-sensitive pacemaker neurons such as ventral lateral neurons ($LN_vs$) were significantly disrupted, but those in temperature-cycle-sensitive pacemaker neurons such as dorsal neurons (DNs) were robust. Our results suggest that the dCLK-controlled TTFL diversify in a pacemaker-neuron-dependent manner which may contribute to specific functions such as different sensitivities to entraining cues.

• Journal of Power Electronics
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• v.14 no.2
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• pp.226-236
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• 2014

A new active LED driver with high power factor (PF) and low total harmonic distortion (THD) compatible with a rapid-start ballast is proposed. An LC input filter is attached to the ballast to increase PF and reduce THD. A boost converter is then installed to regulate the LED current, where an unstable operating region has been newly identified. The unstable region is successfully stabilized by feedback control with two zeroes. The extremely high overall system of the 10th order is completely analyzed by the newly introduced phasor transformed circuits in static and dynamic analyses. Although a small DC capacitor is utilized, the flicker percentage of the LED is drastically mitigated to 1% by the fast controller. The proposed LED driver that employs a simple controller with a start-up circuit is verified by extensive experiments whose results are in good agreement with the design.