• Steel and Composite Structures
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• v.19 no.2
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• pp.467-484
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• 2015

Seismic performances of dual steel moment-resisting frames with mixed use of rigid and semi-rigid connections were investigated to control of the base shear, story drifts and the ductility demand of the elements. To this end, nonlinear seismic responses of three groups of frames with three, eight and fifteen story were evaluated. These frames with rigid, semi-rigid and combined configuration of rigid and semi-rigid connections were analyzed under five earthquake records and their responses were compared in ultimate limit state of rigid frame. This study showed that in all frames, it could be found a state of semi-rigidity and connections configuration which behaved better than rigid frame, with consideration of the base shear and story drifts criterion. Finally, some criteria were suggested to locate the best place of the semi-rigid connections for improvement of the seismic performance of steel moment-resisting frames.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.56
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• pp.19-34
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• 2000

Impact of business process re-engineering requires the fundamental rethinking of how information systems are analyzed and designed. It is no longer sufficient to establish a monolithic system for fixed business environments. Information systems must be adaptive in nature. This demand is also applied in production domain. Enabling concept for the adaptive information system is reusability. This paper presents a new object-oriented analysis process for creating such reusable software components in production domain, especially for production planning and scheduling. Our process called MeCOMA is based on three meta-models: physical object meta-model, data object meta-model, and activity object meta-model. After the three meta-models are extended independently for a given production system, they are collaboratively integrated on the basis of integration pattern. The main advantages of MeCOMA are (1) to reduce software development time and (2) to consistently build reusable production software components.

• Journal of Drive and Control
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• v.16 no.3
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• pp.16-22
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• 2019

Due to the rise in energy consumption and natural resource prices, the demand to improve energy efficiency in the construction machine has been highlighted. Even though many researchers have contributed to the development of the technology, CO2 gas emissions of heavy machinery remains high. One of the most significant problems of the novel excavator with internal combustion engines is the emission of harmful gas. To reduce emissions in the construction machine, it is necessary to replace the internal combustion engines with the alternative one. To overcome those problems, this paper focuses on the adoption of PEMFC hybrid engine for the excavator system. An internal combustion engine is replaced by new structures with fuel cell, battery and ultra capacitor. The proposed system has been designed and modeled using Simcenter Amesim software and compared with the conventional one through simulation results.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.6
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• pp.2893-2907
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• 2019

Wireless mobile communication systems in subway tunnels have been widely researched these years, due to increased demand for the communication applications. As a result, an accurate model is essential to effectively evaluate the communication system performance. Thus, a neoteric three-dimensional (3D) geometry-based stochastic model (GBSM) is proposed for the massive multiple-input multiple-output (MIMO) fading channels in tunnel environment. Furthermore, the statistical properties of the channel such as space-time correlation, amplitude and phase probability density are analyzed and compared with those of the traditional two-dimensional (2D) model by numerical simulations. Finally, the ergodic capacity is investigated based on the proposed model. Numerical results show that the proposed model can describe the channel in tunnels more practically.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.6
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• pp.3219-3237
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• 2019

The Cloud Computing is growing rapidly in the current IT industry. Cloud computing has become a buzzword in relation to Grid & Utility computing. It provides on demand services to customers and customers will pay for what they get. Various "Cloud Service Provider" such as Microsoft Azure, Google Web Services etc. enables the users to access the cloud in cost effective manner. However, security, privacy and integrity of data is a major concern. In this paper various security challenges have been identified and the survey briefs the comprehensive overview of various security issues in cloud computing. The classification of security issues in cloud computing have been studied. In this paper we have discussed security challenges in cloud computing and also list recommended methods available for addressing them in the literature.

• International Journal of Computer Science & Network Security
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• v.21 no.4
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• pp.9-18
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• 2021

Blockchain and its infrastructure technology have expanded rapidly in the last decade and are in high demand, but there is a lack of comprehensive studies on those platforms. Blockchain is a new technology based on the distributed digital ledger system. Decentralized trust is one of the key factors behind the blockchain-based system. Transparency of such a system is better than a conventional centralized ledger system. By using a blockchain-based transaction system, any business organization can harness key benefits like data integrity, confidentiality, and anonymity without involving any third party in control of the transactions. Since the blockchain is used in numerous applications and the horizon is expanding at an unprecedented pace. So, there is a need for an introducing and reviewing of blockchain platforms. In this paper, we have reported a review on existing contemporary blockchain platforms. In particular, From the existing studies, we have identified eighty blockchain platforms and the majority of them have a lack of technical details. To provide the researchers a comprehensive introducing on blockchain platforms to perform a broad guideline for future research and investment in the blockchain domain.

• International Journal of Computer Science & Network Security
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• v.22 no.4
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• pp.329-339
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• 2022

Small cells, particularly femtocells, are regarded a promising solution for limited resources required to handle the increasing data demand. They usually boost wireless network capacity. While widespread usage of femtocells increases network gain, it also raises several challenges. Interference is one of such concerns. Interference management is also seen as a main obstacle in the adoption of two-tier networks. For example, placing femtocells in a traditional macrocell's geographic area. Interference comes in two forms: cross-tier and co-tier. There have been previous studies conducted on the topic of interference management. This study investigates the principle of categorization of interference management systems. Many methods exist in the literature to reduce or eliminate the impacts of co-tier, cross-tier, or a combination of the two forms of interference. Following are some of the ways provided to manage interference: FFR, Cognitive Femtocell and Cooperative Resource Scheduling, Beamforming Strategy, Transmission Power Control, and Clustering/Graph-Based. Approaches, which were proposed to solve the interference problem, had been presented for each category in this work.

• BMB Reports
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• v.55 no.6
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• pp.259-266
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• 2022

Recent studies have revealed that the immune system plays a critical role in various physiological processes beyond its classical pathogen control activity. Even under a sterile condition, various cells and tissues can utilize the immune system to meet a specific demand for proper physiological functions. Particularly, a strong link between immunity and metabolism has been identified. Studies have identified the reciprocal regulation between these two systems. For example, immune signals can regulate metabolism, and metabolism (cellular or systemic) can regulate immunity. In this review, we will summarize recent findings on this reciprocal regulation between immunity and metabolism, and discuss potential biological rules behind this interaction with integrative perspectives.

• Journal of Software Assessment and Valuation
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• v.17 no.1
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• pp.93-99
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• 2021

The demand for online education has rapidly increased due to the influence of COVID-19. One of the biggest challenges in engineering education is how to efficiently conduct experiments online. In this paper, for the virtual experimental system for microcontroller application that is essential for education in the field of electrical, electronic, and control engineering, we described the microcontroller functional modeling and implementation with Java language. The usefulness of the developed microcontroller module has been verified through educational field application.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.32 no.6
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• pp.49-56
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• 2003

CO2환기제어는 신축건물에서 흔히 사용되고 있지만, 기존의 건물에서는 그 적용 예가 흔하지는 않다. 아마도 개보수라는 것이 가능하다고 여겨지는 자원절감이나 이익에 대한 방대한 기록이 요구되기 때문이며 게다가 제어에 관한 개보수는 복잡하다는 인식에 기인한다. 공교롭게도, 에너지 사용 패턴에 대하 명확한 기록이 있는 기존의 건물에 가장 에너지절약적인 기회가 많다는 사실이다. 이 기고문에서는 기존 건물의 CO2개보수에 관하여 그 성능 평가에 대한 방법론을 제시하고 있으며, 현장 평가와 이 방법론을 적용한 A-등급 사무소 건물에서의 개보수를 통한 성능개선에 관하여 분석하고 있다. 대상은 첨단 DDC시스템이 있는 미국 환경청의 에너지스타 등급을 획득한 건물이다.