• Korean Journal of Occupational Health Nursing
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• v.29 no.2
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• pp.133-139
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• 2020

Purpose: This study aimed to identify the influence of consecutive night-shift work and working time on insomnia among hospital nurses. Methods: A descriptive correlational research designutilizing secondary data analysis was adopted. Data on consecutive night-shift work, working time, and insomnia were collected from 64 hospital nurses using a Fitbit activity tracker and questionnaires, and analyzed using hierarchical logistic regression. Results: Consecutive night-shift work for more than three days had a significant influence on insomnia among hospital nurses. Weekly working hours also accounted significantly for the variance in insomnia, exceeding the influence of consecutive night-shift work. Conclusion: Development and implementation of proper schedules to control consecutive night-shift work and working time is important to alleviate insomnia among hospital nurses.

• Journal of Electrical Engineering and information Science
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• v.2 no.6
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• pp.74-81
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• 1997

Xcent-Net is a new system network designed to support a clustered SMP called SPAX(Scalable Parallel Architecture based on Xbar) that is being developed by ETRI. It is a duplicated hierarchical crossbar network to provide the connections among 16 clusters of 128 nodes. Xcent-Net is designed as a packet switched, virtual cut-through routed, point-to-point network. Variable length packets contain up to 64 bytes of data. The packets are transmitted via full duplexed, 32-bit wide channels using source synchronous transmission technique. Its plesiochronous clocking scheme eliminates the global clock distribution problem. Two level priority-based round-robin scheme is adopted to resolve the traffic congestion. Clear-to-send mechanism is used as a packet level flow control scheme. Most of functions are built in Xcent router, which is implemented as an ASIC. This paper describes the architecture and the functional features of Xcent-Net and discusses its implementation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.12 no.5
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• pp.505-518
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• 1987

In this paper, the 2-level and 3-level types of PWM technique have been analyzed, and a multiprocessor has been designed as controller for these two types of PWM inverters. Designed multiprocessor employing a hierarchical structure of a SUPERVISORY PROCESSOR which interconnects three LOCAL PROCESSOR through a common memory technique has showed as elaborate digital control characteristic. Using this multiprocessor configuration the system could gain a great degree of freedom in change of software. Also software was simpler than a single processor configuration.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.05a
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• pp.77-81
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• 2001

In this paper, a RAID system is modeled and simulated by using the DEVS formalism. The RA[D system interacts with a host system by using the high-speed Fibre channel protocol and stores input data in an array of IDE disks. The DEVS formalism specifies discrete event systems in a hierarchical, modular manner. The RAID system model is composed of three units: primary-PCI unit, secondary-PCI unit and CPU unit. The primary-PCI unit interfaces with the host system and caches I/O data. The secondary-PCI unit includes disks. The CPU unit controls overall system. The control algorithm of CPU and PCI transactions are analyzed and modeled. From an analysis of simulation events, we can conclude that the proposed model satisfies given requirements.

• Journal of Communications and Networks
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• v.6 no.2
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• pp.156-162
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• 2004

In recent years, mobile ad-hoc networks have received a great deal of attention in both academia and industry to provide anytime-anywhere networking services. As wireless networks are rapidly deployed, the security of wireless environment will be mandatory. In this paper, we describe a group key management architecture and key agreement protocols for secure communication in mobile ad-hoc wireless networks (MANETs) overseen by unmanned aerial vehicles (UAVs). We use implicitly certified public keys method, which alleviates the certificate overhead and improves computational efficiency. The architecture uses a two-layered key management approach where the group of nodes is divided into: 1) Cell groups consisting of ground nodes and 2) control groups consisting of cell group managers. The chief benefit of this approach is that the effects of a membership change are restricted to the single cell group.

• Journal of the Korean Home Economics Association
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• v.41 no.7
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• pp.91-106
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• 2003

Multiple features of infant day-care are explored, including age of entry, quantity, quality and stability of day-care. And relative contribution of day-care and family factors on maternal behaviors are examined. Data were gathered from 299 mothers who have infants aged under 36 months using self-report questionnaires. Results show that more than 40% infants enter day-care before 6 months of their life and about 85% of infants have far more than 30 hours of care a week. Half of the infants experience different day-care arrangements more than once. Compared to the other types of day-care, frequency of day-care arrangement change and quality of care are highest in private child-care centers. A series of Hierarchical regression results reveal that quality of day care is negatively related to mothers' control behavior whereas positively related to mothers' responsive behavior. But in general, family and child characteristics play a greater role in mothers' parenting behaviors than infant day-care characteristics.

• IE interfaces
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• v.6 no.2
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• pp.53-65
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• 1993

This paper deals with the development of a software module for production planning and scheduling activities of an existing Flexible Machining and Assembly System (FMAS). The Production Planning Module uses the hierarchical and sequential scheme based on "divide and conquer" philosophy. In this module, routes are determined based on the production order, orders are screened, tools are allocated, and order adjustments are executed according to the allocated tools. The Scheduling Module allocates the resources, determines the task priority and the start and completion times of tasks. Re-scheduling can be done to handle unforeseen situations such as lumpy demands and machine breakdowns. Since all modules are integrated with a central database and they interface independently, it is easy to append new modules or update the existing modules. The result of this study is used for operating the real FMAS consisting of a machining cell with 2 domestic NC machines and a part feeding robot, an assembly cell with a conveyor and 3 robots, an inspection cell, an AGV, an AS/RS, and a central control computer.

• 한국정보통신설비학회:학술대회논문집
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• 2008.08a
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• pp.229-232
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• 2008

급격한 이동통신 기술의 발전에 힘입어 음영지역 해소 및 고속 데이터 처리를 위해 댁내 기지국에 대한 개발 및 연구가 진행 중이다. 댁내 기지국은 크게 음영지역 해소를 위한 Open 방식의 기지국과 고속 데이터 처리를 위해 특정 가입자만 사용할 수 있는 Close 방식이 있다. 상기 방식들은 망의 특성에 맞게 이를 제공하는 망 사업자에 의해 선택 된다. 댁내 기지국을 관리하기 위해서는 많은 시간과 인력자원이 소요되므로 자동으로 설정 및 최적화시키는 기능이 요구 시 되고 있으며, 이를 3GPP에서 SON (Self Organizing Optimizing Networks) 이라 일컫고 연구진행 중이다. 본 논문은 댁내 기지국 관리를 위해 셀의 기본 인자인 PCI(Physical Layer Identity) 할당 방안과 댁내 기지국간 간섭을 최소화 시키기 위한 Adaptive Coverage 방안을 제시한다. 또한 계층적 셀 구성(Hierarchical Cell Structure)에 따른 이동성 제공 방안을 제시한다.

• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.538-541
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• 2004

아바타는 최근 각광 받고 있는 기술로서 다양한 분야에서 많은 활용 및 발전이 기대된다. 그러나 현재 아바타 행위 표현 및 제어에는 체계적이고 표준적인 접근 방식이 결여되어 있어 아바타 행위 표현의 어려움이 있는 실정이다 본 논문에서는 다양한 도메인 환경에서 아바타의 제어를 보다 용이하게 하기위해서 아바타 행위 표현의 계층적인 접근 방식을 제안하였다. 이를 위해 작업레벨 스크립트를 정의하여 특정 도메인에서 필요한 작업을 수행하기위한 행위들을 표현하고 추상적인 표현방식의 상위레벨 모션 및 물리적 표현형식의 기본 모션 스크립트를 정의하였다. 이와 같은 접근 방식을 통하여 사용자 측면에서 보다 쉽게 아바타의 행위를 제어할 수 있으며, 계층적인 표현 및 제어방식으로 아바타 모션의 사용자의 제어 용이성, 스크립트의 확장성 및 재사용성을 높였다.

• Journal of the Korea Society for Simulation
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• v.10 no.3
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• pp.59-70
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• 2001

Typical low-level image processing tasks require thousands of operations per pixel for each input image. Traditional general-purpose computers are not capable of performing such tasks in real time. Yet important features of traditional computers are not exploited by low-level image processing tasks. Since storage requirements are limited to a small number of low-precision integer values per pixel, large hierarchical memory systems are not necessary. The mismatch between the demands of low-level image processing tasks and the characteristics of conventional computers motivates investigation of alternative architectures. The structure of the tasks suggests employing an array of processing elements, one per pixel, sharing instructions issued by a single controller. In this paper we implemented various image processing filtering using the format converter. Also, we realized from conventional gray image process to color image process. This design method is based on realized the large processor-per-pixel array by integrated circuit technology This format converter design has control path implementation efficiently, and can be utilize the high technology without complicated controller hardware.