• Journal of the Korean Society of Safety
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• v.32 no.6
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• pp.110-115
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• 2017

Currently, the Ministry of Employment and Labor is strengthening monitor programs in regards to occupational industrial safety and health act compliance in business operations. However, industrial accidents occur persistently. Therefore, the study strives to diagnose and understand the issues in its educational stature, targeting managing supervisors in large scale shipbuilding industry whose completed the regular safety and health act sessions. This research considered a total of 3,252 employees whose completed theory-based cluster sessions for three months since February, 2016. The group is divided into two categories; 551 participants whose completed 8 hours of training and 2,701 participants whose completed 4 hours of training. Technical statistics were used to measure the knowledge of safety and health, educational environment, curriculum and educational effects on managing supervisors. A t-test was used to analyze the difference between the training hours. The result indicated that the target participants' knowledge on safety and health before the session was 50.24 points average (100 point scale), showing low standards in general. In depth analysis indicated that both 8 hours and 4 hours groups scored lowest in educational methods and communications between the lecturer and participants factors within the educational curriculum category. Meanwhile, transition in knowledge acquirement, work attitude, and work behaviors scored the highest in the analysis, showing a high satisfaction factors in educational effects. Therefore, the improvement in educational time and period can increase the efficacy of the educational programs. Also, theory-based cluster programs based on lectures suggests positive influence in knowledge acquirement and behavioral transitions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.8
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• pp.3391-3397
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• 2011

These excavators have been widely used due to their flexibility in handing various tasks via simple changes of their attachments. Since the performance of manually-operated excavators heavily depend on the operators' skill level, there is a strong need for developing automatic excavators in the industry. In order to achieve such goals, exiting approaches have studied direct modification of existing hydraulic systems in the excavator for feed back control of each link. This paper presents a miniaturized automatic excavator that can be used for the development and demonstration of advanced control algorithm for excavators under a safer environment with reduced cost. Two PCs were installed and connected to the excavator through wireless communications for its control and monitoring. Tracking control of each link using a time varying sliding mode controller was performed through experiments on the developed system to demonstrate its ability.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.7
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• pp.9-16
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• 2012

In order to extend cell coverage and to cope with shadow areas, a relay-assisted wireless communications system has been widely studied. In this paper, we propose new equalization method for single carrier (SC) frequency domain equalizer (FDE) in amplify-and-forward (AF) relaying multi-path networks to improve the performance at shadow areas. The performance of SC-FDE system in 3-slot based multi-path networks can be improved considerably with the diversity gain which we obtain by equalizing the combined signal from relays by means of the minimum mean square error (MMSE) criteria. We find the weighting coefficients of maximum ratio combining (MRC) and the tap coefficients of MMSE equalizer for SC-FDE in AF relaying multi-path networks. Simulation results show that the proposed system considerably outperforms the conventional SC-FDE system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.535-544
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• 2018

As the spread of mobile devices equipped with various sensors and high-quality wireless network communications functionsexpands, the amount of spatio-temporal data generated from mobile devices in various service fields is rapidly increasing. In conventional research into processing a large amount of real-time spatio-temporal streams, it is very difficult to apply a Hadoop-based spatial big data system, designed to be a batch processing platform, to a real-time service for spatio-temporal data streams. This paper extends the MapReduce online framework to support real-time query processing for continuous-input, spatio-temporal data streams, and proposes a load management method to distribute overloads for efficient query processing. The proposed scheme shows a dynamic load balancing method for the nodes based on the inflow rate and the load factor of the input data based on the space partition. Experiments show that it is possible to support efficient query processing by distributing the spatial data stream in the corresponding area to the shared resources when load management in a specific area is required.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2708-2714
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• 2009

Due to poor linguistic communication skills of sucklings and infants, crying mostly is only means of communication to express their body conditions and desires. We, therefore, developed an infant auscultation system which detects which part of the body has a pathological problem, by analysing infant's crying sound patterns. Specifically, in this paper, we accomplished an auscultation system for congenital heart diseases detection by performing pitch, intensity and spectrum analysis of the crying sounds between the normal infants group and the congenital heart diseases group. With this system, we can diagnose congenital heart diseases of infants with poor communication capacity, and, in the near future, can build a home care diagnosis system based on crying sound analysis technologies through additional experiments on medical data.

• Journal of Satellite, Information and Communications
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• v.10 no.2
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• pp.90-94
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• 2015

We stuidied liauid crystal alignment treatment using solution process for making thin oxide layer in liquid crystal display. It is the one of very effient and popular process in making thin oxide layer in electronical industrial fields. Particularly, this process has highly potential value in liquid crystal display industrial fields because it cause automatically induced alignment process without tranditional alignment process in liquid crystal alignment process. We made several different kinds of mol density solutions using strontium oxide solution. And those solutions were treated for solidification layers using annealing process for 2 hours. And we stuided pretilt angle properties of these alignment layers of strontium oxide for clarifying the relationship of liquid crystal molecules and thin strontium oxide layer. And we also tested the existence of strontium oxide thin layer on substrate using XPS measurement. We expected the hig gain of electro-optical properties in liquid crystal display using strontium oxide thin layer because it has high K property material than the other metal-based oxide layers. In this results, we measured 1.447 to 1.613 thresholds volts as 0.1 mol to 0.4 mol density in 0.1 mol density steps. This is significant better characteristics than conventional liquid crystal display as higher than 1.85 thresholds volts. And it make possible to making next-generation liquid crystal display which present low-power consumption and wide gray scale in liquid crystal display.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1839-1848
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• 2012

Recently, smartphone communications using Wi-Fi channel are increasing rapidly to provide diverse internet services. The WPA security protocol was used for data protection between user and wireless AP. However, WPA-PSK protocol was known to be weak to the dictionary attack. In this paper, we proposed a secure WPA-PSK protocol to resist the dictionary attack. Since the proposed method was designed to generate a strong encryption key which is combined the Diffie-Hellman key agreement scheme with secrecy property of PSK(Pre-Shared Key), we can protect the Wi-Fi channel from Man-In-The-Middle attack and Rogue AP impersonation attack.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.5162-5168
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• 2013

Hopping sequences of Time Hopped Ultra Wideband Impulse Radio (TH-UWB-IR) system are to mitigate multipath fading and to provide the multiple access chances for multi users. For the reliable communications, the same pulses are repeatedly transmitted for a bit duration based on hopping sequences. The proposed decoding scheme utilizes the intervals of inter-codes in a frame where the short interval between two pulses leads to the large interference by the multipath fading. For a single user case, the proposed method obtains 0.5dB gain over the conventional method at BER=$10^{-3}$. Decoding performance of repeated pulses can be increased using the property of the hopping sequences of multi users.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.708-715
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• 2016

Quality of experience (QoE) for multimedia services in macro-femtocell networks is one of the key issues for 5G mobile and wireless communications. A service management structure needs to guarantee the QoE for mobile users based on end-to-end negotiation to support service continuity. Resource management is necessary to maintain the QoE requirements of different multimedia applications, because service continuity may be impeded by delays. This paper proposes four types of resource management scheme to support consistent QoE for different multimedia services. For this purpose, a QoE structure is suggested, and a resource allocation scheme is proposed by utilizing a fixed amount of radio resources reserved for dedicated use to support QoE. Various multimedia services with different requirements (such as voice, image, and data) can be serviced simultaneously, because QoE can be provided under our proposed scheme. Simulation results show that our scheme provides better performance than a conventional scheme with respect to outage probability and total data throughput.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.86-92
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• 2017

As the elderly population increases, real-time personal health monitoring is gaining new ground with advances in wireless communications. Such an approach is particularly beneficial to elderly and physically challenged people, as well as those who live alone and are not be able to seek help in case of medical emergencies. The aim of this study is to implement a wearable band which monitors personal vital signs, such as the body temperature and heart rate, and assists with healthcare decisions using a fuzzy logic based decision support system. Since the vital sign data measured from sensors are imprecise and their normal variation with age is nonlinear and not crisp, a fuzzy system is employed to deal with this imprecise or uncertain information. The proposed wearable band is designed to continuously capture and transmit vital signs and healthcare decisions to suitable apps developed for smartphones. In this way, health alerts can be sent to the guardian or caregiver who is registered in the apps.