• Journal of Applied Reliability
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• v.14 no.1
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• pp.29-35
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• 2014

To improve the reliability of a weapon system, we perform the activities: setting the target reliability, reliability allocation, and reliability management, etc. Before starting weapon system development, the target reliability of system is set through advanced research and is allocated to its subsystems at the beginning of development. Then we manage the reliability of system and subsystems to meet the target reliability until completion of system development. In this paper, we research representative reliability allocation methods and introduce the suitable reliability allocation method followed by its application to the underwater guided weapon system. The purpose of this research is to review the proposed reliability allocation techniques and find an appropriate method for underwater weapon systems followed by the validation of its application.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.5
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• pp.2299-2318
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• 2019

Location-aware networks are of great importance for both civil lives and military applications. Methods based on line-of-sight (LOS) measurements suffer sever performance loss in harsh environments such as indoor scenarios, where sensors can receive both LOS and non-line-of-sight (NLOS) measurements. In this paper, we propose a data association (DA) process based on the expectation maximization (EM) algorithm, which enables us to exploit multipath components (MPCs). By setting the mapping relationship between the measurements and scatters as a latent variable, coefficients of the Gaussian mixture model are estimated. Moreover, considering the misalignment of sensor position, we propose a space-alternating generalized expectation maximization (SAGE)-based algorithms to jointly update the target localization and sensor position information. A two dimensional (2-D) circularly symmetric Gaussian distribution is employed to approximate the probability density function of the sensor's position uncertainty via the minimization of the Kullback-Leibler divergence (KLD), which enables us to calculate the expectation step with low computational complexity. Moreover, a distributed implementation is derived based on the average consensus method to improve the scalability of the proposed algorithm. Simulation results demonstrate that the proposed centralized and distributed algorithms can perform close to the Monte Carlo-based method with much lower communication overhead and computational complexity.

• The Journal of Korea Robotics Society
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• v.18 no.1
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• pp.99-109
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• 2023

In this paper, the cinch bag typed fruit harvesting gripper was proposed. This gripper is focused on preventing problems that we found from the related research and setting the breakthrough as a design condition according to the harvest failures of other related studies. The cover part is designed to overcome the surrounding obstacles of target fruits such as tomato, Korean melon, and sweet pepper. The measurement of maximum load showed that the well-grasped target object, such as a spherical object with 65 mm of diameter, is unable to slip in a range of 0 kg to 10 kg. The fact that the gripper allows from 4 cm to 6 cm of positional error was shown in the measurement of positional error tolerance. And the cover part of this gripper showed that the suggested gripper can grab a target object without being obstructed by leaves and stems. Finally, it was proved that the gripper satisfied the design conditions through the measurement of contacting force, which showed it is appropriate for grasping an actual fruit without damage.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.696-706
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• 2013

This study aims to develop DEA model which can look into budget cost variance analysis tool based on standard cost using 68 hospital's input and output data. For accomplishing this purpose, by introducing new DEA model which can get an attainable target cost, we can decompose an actual cost difference into several meaningful sub variances. Also based on the 2008 general hospital data, this model can make variance analysis between actual cost and target cost. Total variance can be divided into technical inefficiency variance, price inefficiency variance, allocation inefficiency variance. This study introduces that by using target budget cost concept, traditional actual cost variance can be divided into a technical variance, price variance, budget variance. Finally, we can get result which confirms there does not exist favorable size effects on efficiency and cost management in running a general hospital.

• Journal of the Korean Society for Railway
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• v.14 no.3
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• pp.295-299
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• 2011

According to the national railway safety plan 1 billion US$ have been invested in railway industry every year. As a result, railway accident rate has been reduce to half recent 6 years. Currently, Korea has 3 kinds of national railway safety target, which are accident fatalities, train accident rate, and passenger fatality per passenger kilometer. Increase of railway passengers and train operating companies force to set up new safety target. Current safety target cannot reflect train operator's safety activities because they include suicide and trespass related accidents, which are hard to be controlled by the operators. In order to reflect to the national railway safety plan, new safety targets are proposed in this study.

• Journal of the Korea Fashion and Costume Design Association
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• v.19 no.1
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• pp.71-90
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• 2017

The purpose of this study is to identify the characteristics of currently targeted consumers of the fashion enterprises. It also aims to assess the value of consumer-related variables that are related to market segmentation. In order to identify the characteristics of targeted consumers, the contents of brand concept and target of 143 brands for women's clothing, and 79 brands for men's clothing were qualitatively analyzed. The results are as follows. First, the demographic characteristics of both male and female included the desire to appear younger, and be more youthful in sensibilities than their actual age. In terms of occupation, male had more variety and concreteness than female. Male and female were above middle class, with an emphasis on being a part of the new generation, one that is young, free, healthy, and leisurely. Second, the psychological and behavioral characteristics of both male and female consumers included the benefit sought of the following: rationality, economy, practicality, functionality, individuality, fashionability, and aesthetics. Their fashion orientations were found to be practical, rational, fashionable, expressive of individual style, and aesthetic sensibilities. Their lifestyles were characterized by elements such as rationality, smartness, urban, active, healthy, young, leisurely, and stable. In terms of the spirit, female had a tendency to be intelligent, elegant, and sensitive, while also being self-reliant, self-disciplined, and unafraid of challenging situations. The male consumers had a tendency to be rational, progressive, passionate, and embracing change, with emphasis on legitimacy, honor, success, pride, and affluence. Third, the usefulness of consumer-related variables in targeting consumers was different according to male and female. These results show that there is a need for these variables to be looked at more closely during market segmentation process. This research may be used as base material in setting up the brand concept and the target market.

• The Journal of the Acoustical Society of Korea
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• v.40 no.5
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• pp.401-407
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• 2021

The continuous active sonar technology is effective for detecting and tracking targets because of short target revisiting rate. Generalized Sinusoidal Frequency Modulation (GSFM) pulses suitable for continuous active sonar systems are known to be capable of obtaining high time-bandwidth product while maintaining the orthogonality between pulses. However, it is unknown how to calculate an appropriate length of time to correlate received GSFM pulses in the presence of a target with acceleration. In this paper, we propose a method to calculate the appropriate time length based on the correlation when matching the received signal in the continuous active sonar system using GSFM pulse. The proposed method calculates the correlation according to the acceleration of the target and calculates the signal processing length according to the correlation. It is shown that stable detection performance can be obtained when the signal processing length calculated by the proposed method through the level of the sidelobe is applied.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.1
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• pp.8-14
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• 2014

This research designed Waste Heat Recovery System(WHRS) generation system of 250kW whose working fluid is R-245fa and studied on cycle characteristics by superheater organization. It simulated two conditions; series connection and parallel connection between superheater and evaporator. In simulation of series connection of superheater and evaporator, output of 4.7% could be improved because of the increase of enthalpy by overheating of working fluid. When setting 250kW for target output, cycle flux could be reduced by 4.1%. When setting 250kW as a target output of cycle In parallel connection simulation of superheater and evaporator, cycle flux was reduced as flux of heat source fluid for superheater was increased. So, the maximum 7.9% of working fluid pump's electric power was reduced and there was no big change in cycle efficiency and net efficiency by flux ratio.

• Journal of Intelligence and Information Systems
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• v.18 no.3
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• pp.119-135
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• 2012

Among various recommendation techniques, neighborhood-based Collaborative Filtering (CF) techniques have been one of the most widely used and best performing techniques in literature and industry. This paper proposes new approaches that can enhance the neighborhood-based CF techniques by identifying a few best neighbors (the most similar users to a target user) more accurately with more information about neighbors. The proposed approaches put more weights to the users who have more items co-rated by the target user in similarity computation, which can help to better understand the preferences of neighbors and eventually improve the recommendation quality. Experiments using movie rating data empirically demonstrate simultaneous improvements in both recommendation accuracy and diversity. In addition to the typical single rating setting, the proposed approaches can be applied to the multi-criteria rating setting where users can provide more information about their preferences, resulting in further improvements in recommendation quality. We finally introduce a single metric that measures the balance between accuracy and diversity and discuss potential avenues for future work.

• Journal of the Korean Geotechnical Society
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• v.38 no.8
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• pp.67-74
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• 2022

The setting of the target area for ground stability evaluation during ground excavation is categorized into theoretical and empirical estimation methods and numerical analysis methods. Generally, the applied theoretical and empirical estimation methods include those by Peck (1969), Caspe (1966), and Clough et al. (1990). The numerical analysis method comprehensively considered the current status of the task section (maximum excavation depth section, ground condition vulnerable section, etc.). It reflected the results of performing two and three-dimensional numerical analyses on the weakest section. Therefore, this study shows an example of setting the scope of influence when excavating the vertical and tunnel sections of a 000-line double-track private investment project through the above theoretical, empirical, and numerical analysis methods.