• Journal of Advanced Navigation Technology
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• v.28 no.1
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• pp.116-122
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• 2024

In this paper, course structure and course width were studied among the main performances of the system to derive the required performance of the modulation index, output power, and phase change specifications of the instrument landing system (ILS) localizer power amplifier. To satisfy the course structure's deviation standard (± 5 uA), the difference in depth of modulation (DDM) deviation standard of the carrier with sideband (CSB) amplifier was standardized to ± 1 uA(0.001 DDM). CSB 30 W power amplifier was designed, and through the modulation compensation circuit, sum in depth of modulation (SDM) is 40% ± 0.1% and DDM is ± 0.0005 DDM in the operating output range(45 dBm ~ 35 dBm). In addition, the course width and displacement sensitivity specifications were analyzed through simulation, and the ± 0.1° change applied during comissioning inspection, which is the most stringent standard, was applied. The output variation of the suppressed with sideband only ( SBO) amplifier was ± 2 mW or less, The phase was standardized to within ± 3 ° and the characteristics were satisfied. By applying a compensation circuit according to output power and temperature, stable modulation index, output, and phase characteristics were obtained.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.1
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• pp.1-9
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• 2024

Multivariate Quadratic (MQ)-based digital signature schemes have advantages such as ease of implementation and small signature sizes, making them promising candidates for post-quantum cryptography. To enhance the efficiency of such MQ-based digital signature schemes, utilizing sparse matrices have been proposed, including HiMQ, which has been standardized by Korean Telecommunications Technology Association standard. However, HiMQ shares a similar key structure with Rainbow, which is a representative MQ-based digital signature scheme and was broken by the MinRank attack proposed in 2022. While HiMQ was standardized by a TTA and recommended parameters were provided, these parameters were based on cryptanalysis as of 2020, without considering recent attacks. In this paper, we examine attacks applicable to MQ-based digital signatures, specifically targeting HiMQ, and perform a security analysis. The most effective attack against HiMQ is the combined attack, an improved version of the MinRank attack proposed in 2022, and none of the three recommended parameters satisfy the desired security strength. Furthermore, HiMQ-128 and HiMQ-160 do not meet the minimum security strength requirement of 128-bit security level.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.443-450
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• 2017

Nowadays, Power Line Communication (PLC) is gaining high attention from industry and electric supply companies for the services like demand response, demand side management and Advanced Metering Infrastructure (AMI). The reliable services to consumers using PLC can be provided by utilizing an efficient PLC channel for which sophisticated channel modeling is very important. This paper presents characterization of a Low Voltage (LV) access network for Narrowband Power Line Communications (NB-PLC) using transmission line (TL) theory and a Simulink model. The TL theory analysis not only includes the constant parameters but frequency selectivity is also introduced in these parameters such as resistance, conductance and impedances. However, the proposed Simulink channel model offers an analysis and characterization of capacitive coupler, network impedance and channel transfer function for NB-PLC. Analysis of analytical and simulated results shows a close agreement of the channel transfer function. In the absence of a standardized NBPLC channel model, this research work can prove significant in improving the efficiency and accuracy of NB-PLC communication transceivers for Smart Grid communications.

• Journal of Distribution Science
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• v.14 no.1
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• pp.17-28
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• 2016

Purpose - Given the increasing interest in the Eurasian Initiative, government-wide studies for the construction of the Silk Road Express are currently being conducted. However, the Korean Government has no experience in operating international freight railroads and has not encountered problems in train service plans, international conventions, and customs clearance, which will arise when TKR is connected to TSR, TCR, and TMGR. Research design, data and methodology - Given these conditions, the cases of direct services in international freight railroads between China and Europe are investigated to identify the possible problems in the connection between TKR and continental railroads. This study also identifies the plans for activating Eurasian railroad logistics. Results - For the service of international freight trains, Korea needs to join international conventions, such as OJSD, as a regular member. Furthermore, any relevant international conference after the conclusion of such an agreement is needed for the agreement on train service schedules, fees, and procedures for passing border stations. Conclusions - Customs clearance and relevant documents must be standardized to address the differences in clearance systems between nations.

• Journal of Korean Society for Quality Management
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• v.46 no.3
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• pp.707-716
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• 2018

Purpose: This study aims to analyze the management performance and production efficiency of strawberry farmers who introduced smart farming, one of the primary symbols of the fourth industrial revolution in the agricultural sector. Methods: We conducted an empirical survey of strawberry farms using smart farming and analyzed production efficiency using DEA method. Results: First, difficulties for strawberry farmers introducing smart farming included time and money spent on parts replacement and additional costs due to compatibility problems with existing facilities after the adoption. Second, strawberry farmers using smart farming increased their total income by producing higher yield and improving quality thanks to the competent growth management. Third, the analysis of production efficiencies before and after smart farming found improvement in technical efficiency, pure technical efficiency, and scale efficiency. But, the gaps in technical and scale efficiencies among the farms widened. Conclusion: Based on the results above, following policy suggestions are offered. First, an environment control technology suitable for strawberry farming needs to be developed. Second, the smart farming technology needs to be standardized by the government. Third, new smart farm models need to be developed to accommodate to the facilities and environment in Korea through collecting big data including high-quality data on the environment, growth, and yield. Fourth, continuing education needs to be provided to narrow the gap in smart farming technology among strawberry farmers.

• Special Issue of the Society of Naval Architects of Korea
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• 2009.09a
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• pp.123-129
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• 2009

Ship painting procedures can be divided into two categories; Out-shell plate painting of the hull and the interior painting of each double gull blocks. It is really hard to apply standardized and automated operations to the latter because the double hull blocks contains a variety of complicated supportive materials and pipes to strengthen the ship structure. In addition their poor working conditions cause painting workers to avoid working in them, resulting in the waste of paints and additional pollution issues. So this research, successfully focused on overcoming the difficulties in working in the complicated blocks and the tough working conditions introduces the main details of automatic equipment systems and their transfer algorism which show how the equipment paints the inner sides of a longitudinal stiffener and moves to another automatically.

• IE interfaces
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• v.18 no.4
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• pp.361-369
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• 2005

Postal address information is basis for customer contact channel as well as for the postal logistics such as sorting and dispatching, and the management system has been prepared. It should manage not only address itself but also information of delivery districts and sequences. It is necessary to consider geographic information system (GIS) to be included for intuitive and efficient manipulation. In order to construct a integrative system that could manage and utilize the standardized postal address information, we analyze various user requirements, define required GIS information, and present some results of data and process modeling. In addition, we explain several main functions with screen-shots of the implemented system. The GIS-enabled system, which is constructed after this study, is planned to be used to build and manage a database of nationwide postal addresses. It would make it possible to present other postal information systems with the address information and to provide various customer services.

• Journal of Energy Engineering
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• v.20 no.2
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• pp.154-162
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• 2011

PMT(Preventive Maintenance Template) is a standardized maintenance program that describes maintenance items & period as operation condition to increase component reliability at the component level. The existing maintenance programs are focused on time based maintenance to inspect and repair component depend on fixed period. But recently, we have developed advanced maintenance program(named PMT) to increase reliability and optimize maintenance program of the plant significant component. This paper presents how to develop the PMT for nuclear power plant's static exciter.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.2
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• pp.291-298
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• 2012

While attempting to develop low salt, low fat and high fibre chicken nuggets, the effect of partial (40%) common salt substitution and incorporation of chickpea hull flour (CHF) at three different levels viz., 5, 7.5 and 10% (Treatments) in pre-standardized low fat chicken nuggets (Control) were observed. Common salt replacement with salt substitute blend led to a significant decrease in pH, emulsion stability, moisture, ash, hardness, cohesiveness, gumminess and chewiness values while incorporation of CHF in low salt, low fat products resulted in decreased emulsion stability, cooking yield, moisture, protein, ash, color values, however dietary fibre and textural properties were increased (p<0.01). Lipid profile revealed a decrease in total cholesterol and glycolipid contents with the incorporation of CHF (p<0.01). All the sensory attributes except appearance and flavor, remained unaffected with salt replacement, while addition of CHF resulted in lower sensory scores (p<0.01). Among low salt, low fat chicken nuggets with CHF, incorporation CHF at 5% level was found optimum having sensory ratings close to very good. Thus most acceptable low salt, low fat and high fibre chicken nuggets could be developed by a salt replacement blend and addition of 5% CHF.

• Journal of Korean Society of Rural Planning
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• v.10 no.4 s.25
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• pp.1-7
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• 2004

In Korea, rural community has been becomming unstable by declining of agriculture. In order to solve this problem, there were some trials to activate rural communities by maintaining rural amenities. But, it is difficult to use rural amenities as a development factor to promote rural communities because there are few researches about quantifying rural amenities. In this study, a method fer quantifying rural amenities is suggested using database normalization technique. Previous thirty seven surveying items of rural amenity resources are formally reduced to five common surveying items, seven resources, and eleven surveying tables. Finally, big picture of rural amenity resource map with surveying data for rural development is suggested.