• Journal of Power Electronics
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• 제6권1호
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• pp.18-28
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• 2006

The Electric Power Subsystem (EPS) is one of the most critical systems on any satellite because nearly every subsystem requires power. This makes the choice of power systems the most important task facing satellite designers. The main purpose of the Satellite EPS is to provide continuous, regulated and conditioned power to all the satellite subsystems. It has to withstand radiation, thermal cycling and vacuums in hostile space environments, as well as subsystem degradation over time. The EPS power characteristics are determined by both the parameters of the system itself and by the satellite orbit. After satellite separation from the launch vehicle (LV) to its orbit, in almost all situations, the satellite subsystems (attitude determination and control, communication and onboard computer and data handling (OBC&DH)), take their needed power from a storage battery (SB) and solar arrays (SA) besides the consumed power in the EPS management device. At this point (separation point, detumbling mode), the satellite's angular motion is high and the orientation of the solar arrays, with respect to the Sun, will change in a non-uniform way, so the amount of power generated by the solar arrays will be affected. The objective of this research is to select satellite EPS component types, to estimate solar array illumination parameters and to determine the efficiency of solar arrays during both detumbling and normal operation modes.

• Structural Engineering and Mechanics
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• 제23권5호
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• pp.455-468
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• 2006

Smart structural systems are defined as ones that demonstrate the ability to modify their characteristics and/or properties in order to respond favorably to unexpected severe loading conditions. The performance of such a task requires a set of additional components to be integrated within such systems. These components belong to three major categories, sensors, processors and actuators. It is wellknown that all structural systems entail some level of uncertainty, because of their extremely complex nature, lack of complete information, simplifications and modeling. Similarly, sensors, processors and actuators are expected to reflect a similar uncertain behavior. As it is imperative to be able to evaluate the impact of such components on the behavior of the system, it is as important to ensure, or at least evaluate, the reliability of such components. In this paper, a system model for reliability assessment of smart structural systems is outlined. The presented model is considered a necessary first step in the development of a reliability assessment algorithm for smart structural systems. The system model outlines the basic components of the system, in addition to, performance functions and inter-relations among individual components. A fault tree model is developed in order to aggregate the individual underlying component reliabilities into an overall system reliability measure. Identification of appropriate limit states for all underlying components are beyond the scope of this paper. However, it is the objective of this paper to set up the necessary framework for identifying such limit states. A sample model for a three-story single bay smart rigid frame, is developed in order to demonstrate the proposed framework.

• 한국게임학회 논문지
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• 제4권3호
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• pp.21-28
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• 2004

게임개발 프로젝트의 설계는 프로세스 구성과 게임 소프트웨어의 프로그램 산출물과 태스크의 관리는 개발자간에 연계하여 구성해야 한다. 기존 개임개발 프로젝트 설계는 프로젝트 활동의 정의 및 변경을 지원하고, 형상관리 도구는 버전제어, 작업공간 관리, 빌드 관리 등을 지원한다. 본 논문의 설계도구는 UML을 사용하여 게임 컴포넌트 기반 개발 프로세스 모델을 설계하고, 프로세스의 진행 상태 기록, 변경 요청에 따른 처리, 태스크별 작업 진행 보고서 작성, 산출물 등록과 변경, 버전 기록, 산출물 또는 서식 검색 등의 기능을 연구하였다. 또한 시스템 설계를 사용함으로써 게임 공학 활동에 참여하는 개발자들이 분산 개발 환경에서 게임 소프트웨어 개발에 필요한 정보와 산출물 관리를 생산성 있게 할 수 있다. 이 시스템 구성에 따라 정보를 공유하면서 설계의 체계화 및 표준화를 수행 할 수 있다.

• International Journal of Automotive Technology
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• 제8권5호
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• pp.575-581
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• 2007

As current and future automobile emission regulations become more stringent, the research on flow distribution for an exhaust manifold and close-coupled catalyst(CCC) has become an interesting and remarkable subjects. The design of a CCC and exhaust manifold is a formidable task due to the complexity of the flow distribution caused by the pulsating flows from piston motion and engine combustion. Transient flow at the exhaust manifold can be analyzed with various computational fluid dynamics(CFD) tools. However, the results of such simulations must be verified with appropriate experimental data from real engine operating condition. In this study, an experimental approach was performed to investigate the flow distribution of exhaust gases for conventional cast types and stainless steel bending types of a four-cylinder engine. The pressure distribution of each exhaust sub-component was measured using a simulated dynamic flow bench and five-hole pitot probe. Moreover, using the results of the pitot tube measurement at the exit of the CCC, the flow distribution for two types of manifolds(cast type and bending type) was compared in terms of flow uniformity. Based on these experimental techniques, this study can be highly applicable to the design and optimization of exhaust for the better use of catalytic converters to meet the PZEV emission regulation.

• Structural Engineering and Mechanics
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• 제37권1호
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• pp.17-37
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• 2011

This paper presents a new Internet-based computational framework for the realistic simulation of multi-scale response of structural systems. Two levels of parallel processing are involved in this frame work: multiple local distributed computing environments connected by the Internet to form a cluster-to-cluster distributed computing environment. To utilize such a computing environment for a realistic simulation, the simulation task of a structural system has been separated into a simulation of a simplified global model in association with several detailed component models using various scales. These related multi-scale simulation tasks are distributed amongst clusters and connected to form a multi-level hierarchy. The Internet is used to coordinate geographically distributed simulation tasks. This paper also presents the development of a software framework that can support the multi-level hierarchical simulation approach, in a cluster-to-cluster distributed computing environment. The architectural design of the program also allows the integration of several multi-scale models to be clients and servers under a single platform. Such integration can combine geographically distributed computing resources to produce realistic simulations of structural systems.

• Journal of Semiconductor Engineering
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• 제2권3호
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• pp.136-141
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• 2021

This paper analyzes the tree expansion for multiple-input multiple-output (MIMO) detection in the viewpoint of hardware implementation. The tree expansion is to calculate path metrics of child nodes performed in every visit to a node while traversing the detection tree. Accordingly, the tree-expansion unit (TEU), which is responsible for such a task, has been an essential component in a MIMO detector. Despite the paramount importance, the analyses on the TEUs in the literature are not thorough enough. Accordingly, we further investigate the hardware complexity of the TEUs to suggest a guideline for selection. In this paper, we focus on a pair of major ways to implement the TEU: 1) a full parallel realization; 2) a transformation of the formulae followed by common subexpression elimination (CSE). For a logical comparison, the numbers of multipliers and adders are first enumerated. To evaluate them in a more practical manner, the TEUs are implemented in a 65-nm CMOS process, and their propagation delays, gate counts, and power consumptions were measured explicitly. Considering the target specification of a MIMO system and the implementation results comprehensively, one can choose which architecture to adopt in realizing a detector.

• Safety and Health at Work
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• 제10권2호
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• pp.151-165
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• 2019

Background: Despite improvements in safety performance, the number and severity of mining-related injuries remain high and unacceptable, indicating that further reduction can be achieved. This study examines occupational accident statistics of the Ghanaian mining industry and identifies priority areas, warranting intervention measures and further investigations. Methods: A total of 202 fatal and nonfatal injury reports over a 10-year period were obtained from five mines and the Inspectorate Division of the Minerals Commission of Ghana, and they were analyzed. Results: Results of the analyses show that the involvement of mining equipment, the task being performed, the injury type, and the mechanism of injury remain as priorities. For instance, mining equipment was associated with 85% of all injuries and 90% of all fatalities, with mobile equipment, component/part, and hand tools being the leading equipment types. In addition, mechanics/repairmen, truck operators, and laborers were the most affected ones, and the most dangerous activities included maintenance, operating mobile equipment, and clean up/clearing. Conclusion: Results of this analysis will enable authorities of mines to develop targeted interventions to improve their safety performance. To improve the safety of the mines, further research and prevention efforts are recommended.

• The Journal of Asian Finance, Economics and Business
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• 제9권5호
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• pp.213-224
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• 2022

In recent years, gamification has been a hot issue due to its positive impact on organizational success. The proper application of game elements in an organizational context is required for gamification implementations. Gamification remains an area of active research for its behavior molding potential. Employee engagement is a critical component in assessing employee behavior and is considered crucial for organizational success. Research questionnaires were completed online between March 2021 and February 2022. Our targeted sample encompassed low and mid-level personnel of Asian and Middle eastern employees working in Hungary. The questionnaire was introduced using google forms. Our sample size consisted of 203 respondents (N = 203). Research results indicated gamification's significance in increasing employees' intrinsic motivation and therefore boosting organizational engagement levels. Gamification improved employees' task performance and the overall quality of work. Organizational culture had a mediating role between gamification and employees' behavior. Organizational culture and employee behavior are in close correlation. Research findings also proved engagements' mediating effect on employees' behavior. The results of the research showed that gamification in human resources has risen in popularity, especially in terms of its impact on employee behavior and performance. The study's findings demonstrated that gamification has a positive impact on organizational performance and collaboration.

• 로봇학회논문지
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• 제19권1호
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• pp.130-138
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• 2024

High-precision 3D Object Detection is a crucial component within autonomous driving systems, with far-reaching implications for subsequent tasks like multi-object tracking and path planning. In this paper, we propose a novel approach designed to enhance the performance of 3D Object Detection, especially in heading angle estimation by employing a moving object segmentation technique. Our method starts with extracting point-wise moving labels via a process of moving object segmentation. Subsequently, these labels are integrated into the LiDAR Pointcloud data and integrated data is used as inputs for 3D Object Detection. We conducted an extensive evaluation of our approach using the KITTI-road dataset and achieved notably superior performance, particularly in terms of AOS, a pivotal metric for assessing the precision of 3D Object Detection. Our findings not only underscore the positive impact of our proposed method on the advancement of detection performance in lidar-based 3D Object Detection methods, but also suggest substantial potential in augmenting the overall perception task capabilities of autonomous driving systems.

• International Journal of Computer Science & Network Security
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• 제24권5호
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• pp.103-110
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• 2024

In the quickly developing world, the idea of the conventional advancement needs to advance[1]. When applied to the advanced work environment, the conventional strategies give as much damage as they do great. Tragically, an absence of versatility in the customary techniques has prompted an inflexible work structure that is truly not viable with the present business. The Agile technique is, subsequently, a more adequate practice, in view of creating programming at a faster speed, while as yet looking after proficiency. The coordinated programming improvement strategies are concentrated in this paper. As per study results, Agile software development group needs solid client association; great light-footed task the executives' measures; item proprietor expands business esteem conveyed by group and need and draw in partners; great deft designing procedures or practices; and great advancements and advancement apparatuses[2]. This examination has suggestions for positive social change since associations that comprehend the basic components might have the option to improve project the executives' systems and money saving advantages prompting higher effectiveness, productivity, and efficiency hence profiting the board, representatives, and client. This survey paper incorporates various methodologies of Agile and their analysis.