• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.4
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• pp.457-466
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• 2005

In this paper, we propose a wavelet neural network(WNN) based predictive control method for path tracking of mobile robots with multi-input and multi-output. In our control method, we use a WNN as a state predictor which combines the capability of artificial neural networks in learning processes and the capability of wavelet decomposition. A WNN predictor is tuned to minimize errors between the WNN outputs and the states of mobile robot using the gradient descent rule. And control signals, linear velocity and angular velocity, are calculated to minimize the predefined cost function using errors between the reference states and the predicted states. Through a computer simulation for the tracking performance according to varied track, we demonstrate the efficiency and the feasibility of our predictive control system.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.7
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• pp.807-813
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• 2016

The Maritime Traffic Safety Audit Scheme was institutionalized in 2009 to provide for professional surveys, measurement and the evaluation of navigational hazards that might occur in coastal waters in the course of marine work. Related researches that dealt with the reform of the Maritime Traffic Safety Audit Scheme found that there were no rules or regulations for verifying whether marine work conformed to audit results and reviewing the exactitude of ship handling simulations which were a crucial part of the scheme. According to the necessity of adopting an ex post facto management system in the field of maritime traffic, this study analyzed the similar audit acts such as the Natural Environment Impact Audit Scheme and the Road Traffic Safety Audit Scheme, and proposed specific articles for revising Maritime Safety Act in order to break out from the institutional inertia of the current Maritime Traffic Safety Audit Scheme. It is expected that a newly proposed legal system for verifying the performance of audit results and the exactitude of audits will help improve maritime traffic safety by eradicating potentially hidden hazards related to marine work.

• Journal of the Korean Dietetic Association
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• v.21 no.1
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• pp.37-56
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• 2015

This study was conducted to develop job standards for clinical dietitian administering clinical nutrition therapy to diabetic patients in hospitals. Based on DACUM (Developing A Curriculum) analysis of 17 members including clinical dietitians, professors majoring in clinical nutrition and researchers, information on duties, tasks and task elements of clinical dietitians for diabetes care were derived and applied to diabetes mellitus-specific clinical nutrition care in hospitals for evaluation. The final developed job standards for clinical dietitians for diabetes care included four duties, 19 tasks and 56 task elements. The duties consisted of nutrition assessment, nutrition diagnosis, nutrition intervention, and nutrition monitoring evaluation. For application of diabetes mellitus-specific job standards in clinical nutrition care, 108 work activities were developed and classified into 90 basic and 18 recommended types. Performance rates of standardized jobs were 80.2% at nutrition assessment, 99.6% at nutrition diagnosis, 78.5% at nutrition intervention, and 32.9% at nutrition monitoring evaluation. These results can be applied as guidelines to implement jobs for diabetes mellitus-specific clinical nutrition services in clinical settings. In addition, they would be useful for education standards in educational institutions for education and training of clinical dietitian.

• Korean Journal of Materials Research
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• v.23 no.2
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• pp.128-134
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• 2013

A study on the corrosion behavior of Inconel alloys and Incoloy 800H in molten salt of LiCl-$Li_2O$ was investigated at $650^{\circ}C$ for 24-312 hours in an oxidation atmosphere. The order of the corrosion rate was Inconel 600 < Inconel 601 < Incoloy 800H < Inconel 690. Inconel 600 showed the best performance suggesting that the content of Fe, Cr and Ni are the important factor for corrosion resistance in hot molten salt oxidation conditions. The corrosion products of Inconel 600 and Inconel 601 were $Cr_2O_3$ and $NiFe_2O_4$, In case of Inconel 690, a single layer of $Cr_2O_3$ was formed in the early stage of corrosion and an outer layer of $NiFe_2O_4$ and inner layer of $Cr_2O_3$ were formed with an increase of corrosion time. In the case of Incoloy 800H, $Cr_2O_3$ and $FeCr_2O_4$ were observed. Most of the outer scale of the alloys was observed to be spalled from the results of the SEM analysis and the unspalled scale which adhered to the substrate was composed of three layers. The outer layer, the middle one, and the inner one were Fe, Cr, and Ni-rich, respectively. Inconel 600 showed localized corrosion behavior and Inconel 601, 690 and Incoloy 800H showed uniform corrosion behavior. Ni improves the corrosion resistance and too much Cr and/or Fe content deteriorates the corrosion resistance.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.291-296
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• 2011

This paper presents energy self-sufficiency simulated in municipal wastewater treatment plants (WWTPs) by adopting solar energy production systems that vary with installation conditions. Relative to the national average energy consumption in WWTPs, the employment of 100 kW photovoltaics (PVs) was simulated to achieve 2.75% of energy self-sufficiency. The simulated results suggested that the installation of PVs toward South or South west would produce the highest energy self-sufficiency in WWTPs. When super-hydrophilic coating was employed in the conventional PVs, 5% of additional solar energy production was achievable as compared to uncoated conventional PVs. When 100 kW of PVs were installed in a future test-bed site, Kihyeung Respida located in Yougin, Sourth Korea, the energy self-sufficiency by solar energy was simulated to be 1.77% (2010). The simulated energy self-sufficiency by azimuth(direction) will be useful reference for practitioners in designing the solar PV systems in the WWTPs.

• Journal of muscle and joint health
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• v.18 no.2
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• pp.169-181
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• 2011

Purpose: This paper presents the development process and the final contents of the sellf- management education program integrated with exercise training (Healthy Aging Happy Aging, HAHA program) for community residing older adults with chronic diseases. Methods: The program evaluation methodology was applied which is an interactive program development process based on needs assessment, formative evaluation, process evaluation and outcome evaluation. The program was developed and revised while the program was implementing to 22 hypertension (HT) and 32 diabetic (DM) participants. Results: The final program has two sub-programs for HT and DM participants utilizing self-efficacy resources. They share four common components; 1) health screening of exercise risks, 2) weekly 1-hour group self-management education classes, 3) biweekly 1-hour group exercise training and 4) a mid-term individual counseling. Both sub-programs were 12-weeks long but have different education and exercise contents. Participants-rated mean satisfaction scores were 3.47/4 and 3.61/4 for HT and DM program respectively. Attendance rate were 83.1% ~ 92.3% for the classes. Conclusion: The HAHA program developed by multidisciplinary team which reflected participants needs was accepted well by participants evidenced by high attendance rate and perceived satisfaction level.

• Journal of Aerospace System Engineering
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• v.14 no.spc
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• pp.31-38
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• 2020

The aircraft system safety assessment, which is emphasized in the development and certification of aircraft, is a systematic and comprehensive evaluation process to determine that all relevant failure conditions have been identified and that all significant combinations of failures cannot result in unacceptable hazards. As the aircraft systems become more complex and require integrated function and performance, proper safety objectives must be established and appropriate assessments are need to be accompanied. This paper has prepared to propose the efficient probabilistic analysis of failure data to evaluate the risk level over the entire aircraft lifecycle through the safety assessment and to review the considerations for aircraft certification and safety improvement.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.5
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• pp.239-247
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• 2013

In network based on multi-interface, there are needed channel assignment strategy that reduce interference and improve bandwidth efficiency by assigning each interface to available channels in order to utilize effectively multiple wireless interfaces on each node. MCS protocol had been proposed, which improve capacity and throughput of network by using hybrid assignment. MCS uses as the criterion to assign channel the number of node that use the same channel in contention area. but there have an problem that this information exactly does not reflect actually offered channel load. in this paper, we proposes CAMCS protocol to assign channel by that the channel busy degree to indicate the occupancy rate of channel by nodes as well as the number of nodes that use the same channel in inference area is used as criterion for estimation channel load, and conform performance improvement effect by simulation.

• Journal of the Korean Society for Railway
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• v.20 no.4
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• pp.448-457
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• 2017

In this paper, for high speed railway propulsion systems, a single phase PWM Converter using discontinuous PWM (DPWM) was investigated. The conventional PWM Converter uses a low frequency modulation index of less than 10 to reduce switching losses due to high power characteristics, which results in low control frequency bandwidth and requires an additional compensation method. To solve these problems, the DPWM method, which is commonly used in three phase PWM Inverters, was adopted to a single phase PWM Converter. The proposed method was easily implemented using offset voltage techniques. Method can improve the control performance by doubling the frequency modulation index for the same switching loss, and can also bring the same dynamic characteristics among switches. Proposed DPWM method was verified by simulation of 100 kW PWM converter.

• Journal of the Korea Concrete Institute
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• v.23 no.6
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• pp.817-826
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• 2011

Concrete using eco-cement has a problem with long-term strength development. However, currently, a long-term strength development mechanism is not confirmed, resulting in a lack of application of eco-cement in construction fields. In this study, the curing humidity influence on development in long-term strength of concrete using eco-cement and the relationship between strength and pore structure were examined. The results showed that wet cured eco-cement with a high water/cement ratio showed serious long-term strength reduction due to non-reduction of pore volume (pore size over 10 nm) in mortar caste with eco-cement. Also, the study results on improvement of long-term strength of eco-cement by partial replacement with ordinary portland cement and finely-ground fly ash showed that both of these alternatives improved long-term strength of concrete caste with eco-cement due to gradual refinement of their micro-structure.