• International Journal of Computer Science & Network Security
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• 제22권4호
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• pp.27-32
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• 2022

The fifth generation (5G) mobile communication technology is designed to meet all communication needs. Heterogeneous networks (HetNets) are a new emerging network structure. HetNets have greater potential for radio resource reuse and better service quality than homogeneous networks since they can evolve small cells into macrocells. Effective resource allocation techniques reduce inter-user interference while optimizing the utilization of limited spectrum resources in HetNets. This article discusses resource allocation in 5G HetNets. This paper explains HetNets and how they work. Typical cell types in HetNets are summarized. Also, HetNets models are explained in the third section. The fourth component addresses radio resource control and mobility management. Moreover, future study in this subject may benefit from this article's significant insights on how HetNets function.

• 한국정보처리학회논문지
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• 제2권3호
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• pp.335-342
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• 1995

본 연구는 패트리네트를 이용한 소프트웨어의 이해용이성에 기인한 효율적인 복 잡도방법을 제시한다. 일반적으로 제어의 흐름에 있어서는 순차성과 조건문 그리고 반복문에 의한 구조적인 구분이 가능하므로 본 논문에서는 그러한 구조적인 부문을 패트리네트로 표현하여 각각의 이해용이성에 기인한 복잡도를 산출하여 종합적인 총 복잡도를 산출하였다. 또한 기존의 다른 복잡도와의 상관관계를 분석함으로 새로운 복 잡도의 신뢰성도 증명하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.336-341
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• 1993

Automatic Assembly Systems(AAS) are a class of systems exhibiting concurrency, asynchronicity and distributedness, and can be modeled by Petri Nets. In this paper, we design two types of configuration of part-assembly system in the car manufacturing line, as an example of AAS. And, we make a modeling the system by utilizing Extended Petri Nets, simulation as varying machine parameters, and analysis of operation status. These enable to present the information of optimal status and various problems occurring in the system for achieving high production rate.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.57-57
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• 2000

The purpose of this paper is show that an chip mounter can be modeled by stochastic petri nets, and that the simulator to verify a fitness of the program to assemble. The chip mounter can be constructed by using the petri net class (CPetriNet) based on the object-oriented programming. By using this simulator, we can get the information about the description of motion of the chip mounter, and moreover, we can evaluate the productivity.

• 전자공학회논문지A
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• 제32A권4호
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• pp.1-14
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• 1995

A new stochastic Petri nets model, called Stochastic Petri Nets Reward Model(SPNRM) is used for modeling and evaluating the performance of telecommunication protocols. We have developed a SPNRM of the TDX-10 Internal protocol, which has a packet data exchange facility between DCEs, Especially a timer and retransmission handling model is presented for error control of the data transmission phase. The stochastic Petri nets package(SPNP), a software package for SPNRM used in this paper, has been used to generate numerical results by analytical-numerical method rather than simulation. From the steady state solution of the net, it is possible to calculate automatically the performance measure of the protocol medeled with both end-to-end and link-by-link method, which are the mean response times and the throughputs.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권6호
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• pp.1979-1995
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• 2015

Network convergence is regarded as the development tendency of the future wireless networks, for which self-organization paradigms provide a promising solution to alleviate the upgrading capital expenditures (CAPEX) and operating expenditures (OPEX). Self-optimization, as a critical functionality of self-organization, employs a decentralized paradigm to dynamically adapt the varying environmental circumstances while without relying on centralized control or human intervention. In this paper, we present comprehensive surveys of heterogeneous networks (HetNets) and investigate the enhanced self-optimization models. Self-optimization approaches such as dynamic mobile access network selection, spectrum resource allocation and power control for HetNets, etc., are surveyed and compared, with possible methodologies to achieve self-optimization summarized. We hope this survey paper can provide the insight and the roadmap for future research efforts in the self-optimization of convergence networks.

• International Journal of Computer Science & Network Security
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• 제22권4호
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• pp.139-146
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• 2022

Wireless access technologies are emerging to enable high data rates for mobile users and novel applications that encompass both human and machine-type interactions. An essential approach to meet the rising demands on network capacity and offer high coverage for wireless users on upcoming fifth generation (5G) networks is heterogeneous networks (HetNets), which are generated by combining the installation of macro cells with a large number of densely distributed small cells Deployment in 5G architecture has several issues because to the rising complexity of network topology in 5G HetNets with many distinct base station types. Aside from the numerous benefits that dense small cell deployment delivers, it also introduces key mobility management issues such as frequent handover (HO), failures, delays and pingpong HO. This article investigates 5G HetNet mobility management in terms of radio resource control. This article also discusses the key challenges for 5G mobility management.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.720-723
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• 1997

This paper presents a cooperative control method for multiple robots. This method is based on local sensors. The proposed method integrates all information obtained by local perception through a set of sensors and generates commands without logical conflicts in designing control logic. To control multiple robots effectively, a global control strategy is proposed. These methods are constructed by using AND/OR logic and transition firing sequences in Petri nets. To evaluate these methods, the object-searching task is introduced. This task is to search an object like a box by two robots and consists of two sub-tasks, i.e., a wall tracking task and a robot tracking task. Simulation results for the object-searching task and the wall tracking task are presented to show the effectiveness of the method.

• Transactions on Control, Automation and Systems Engineering
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• 제3권4호
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• pp.203-209
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• 2001

This paper develops a control method for some generic formation tasks of multiple mobile robots with inaccurate sensor information. Inaccurate sensor information means that all the robots have only local sensors that cannot accurately measure absolute distances and directions of objects. That is, all the sensors have limitation on the range, and uncertainty in the values. Therefore, more robust and reliable control logic is proposed and implemented. The logic is developed considering generic situations and increasing the number of robots participating in the formation. Petri nets are used for modeling and design of the control logic, which can visualize the control models and make it easy to check the states of each robot. Physically homogeneous mobile robots are designed and built to evaluate the developed logic. Each robot is equipped with eighteen infrared sensors and a UHF transceiver module. The experiment results are analyzed quantitatively by using the data of the relative distances and angles between the robots. And the trajectories of the robots during the formation are also evaluated. The developed control approach is demonstrated with experiments to be successful and efficient for the formation of autonomous mobile robots.

• 정보보호학회논문지
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• 제13권5호
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• pp.81-90
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• 2003

기존 웹 기반인 시스템 관리 소프트웨어 솔루션들은 시간적, 공간적 제약을 갖는다. 그리고 오류 메시지에 대한 불확실한 통보와 실시간 지원요구 및 긴급조치가 어렵다는 문제점들을 갖는다. 이러한 문제들을 해결하기 위해서 모바일 통신기기를 이용하여 원격시스템을 관리 및 모니터링하고 즉각적으로 원격지의 시스템을 제어할 수 있는 무선 원격제어 시스템을 설계 및 구현하였다. 구현된 무선 원격제어 시스템은 이러한 문제의 해결뿐만 아니라 보안의 문제도 갖고 있다. 그러므로 본 논문에서는, 무선 원격제어 시스템을 위한 보안 문제에 초점을 맞추어 진행하였으며, 설계한 보안기능은 사용자에 대한 모바일장비 사용자 인증과 대상 시스템 접근제어 기능을 갖도록 하였다. 이러한 보안 기능에 대한 안전성 검증을 위하여 각 단계에 대한 모든 가능한 상태를 표현할 수 있는 CPN(Coloured Petri Nets)을 도입하였다. 그리고 본 논문에서는 CPN 기반의 상태 불변식으로 안전성을 검증하였다. 제안한 보안 기능의 CPN 표현과 분석방법은 차후에 다른 서비스 모델의 설계와 검증에 유용한 방법이 될 수 있다.