• The Journal of Engineering Research
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• v.2 no.1
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• pp.73-82
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• 1997

In this paper, we examine design trends in the development of distributed real-time system. Many real-time systems developed over the last ten years share common characteristics including use of communications, imprecise computations, the object-oriented paradigm, multiprocessor node hardware, dynamic time-driven scheduling and the inclusion of fault tolerance mechanisms. By examining the major design decisions made in previous systems, the best attributes of these systems can be coalesced together to form the "ideal" real-time system. This paper examines such a system and the advantages and disadvantages of the design decisions involved.

• Journal of KIISE:Databases
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• v.27 no.2
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• pp.227-237
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• 2000

A Web database System is a large-scaled multimedia application system that has multimedia processing facilities and cooperates with relational/Object-Oriented DBMS. Conventional hypertext modeling methods and DB gateway have limitations for Web database because of their restricted versatile presentation abilities and inefficient concurrency control caused by bottleneck in cooperation processing. Thus, we suggest a Dynamic Navigation Model & Virtual Graph Structure. The Dynamic Navigation Model supports implicit query processing and dynamic creation of navigation spaces, and introduce node-link creation rule considering navigation styles. We propose a mapping methodology between the suggested hypertext model and the relational data model, and suggest a dynamic allocation scheduling technique for query processing server based on weighted value. We show that the proposed technique enhances the retrieval performance of Web database systems in processing complex queries concurrently.

• ETRI Journal
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• v.36 no.1
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• pp.80-88
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• 2014

Recently, the idea of the smart grid has been gaining significant attention and has become a hot research topic. The purpose of this paper is to present a novel smart grid management scheme that uses game theory principles. In our proposed scheme, power appliances in the smart grid adaptively form groups according to the non-cooperative hedonic game model. By exploiting multi-appliance diversity, appliances in each group are dynamically scheduled in a cooperative manner. For efficient smart grid management, the proposed coopetition game approach is dynamic and flexible to adaptively respond to current system conditions. The main feature is to maximize the overall system performance while satisfying the requirements of individual appliances. Simulation results indicate that our proposed scheme achieves higher energy efficiency and better system performance than other existing schemes.

• Proceedings of the KSPS conference
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• 2007.05a
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• pp.327-329
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• 2007

This paper presents a FSN-based LVCSR system and it's application to the speech TV program guide. Unlike the most popular statistical language model-based system, we used FSN grammar based on the graph theory-based FSN optimization algorithm and knowledge-based advanced word boundary modeling. For the memory and latency efficiency, we implemented the dynamic pruning scheduling based on the histogram of active words and their likelihood distribution. We achieved a 10.7% word accuracy improvement with 57.3% speedup.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.7
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• pp.589-596
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• 2001

In this paper, a new design methodology for the optimal control of nonlinear systems described by the TS(Takagi-Sugeno) fuzzy model is proposed. First, a new theorem concerning the optimal stabilizing control of a general nonlinear dynamic system is proposed. Next, based on the proposed theorem and the inverse optimal approach, an optimal controller synthesis procedure for a TS fuzzy system is given, Also, it is shown that the optimal controller can be found by solving a linear matrix inequality problem. Finally, the proposed method is applied to the attitude control of a rigid spacecraft to demonstrate its validity.

• Journal of KIISE:Information Networking
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• v.33 no.2
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• pp.113-130
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• 2006

Recently with the explosive growth of Internet applications, the attacks of hackers on network are increasing rapidly and becoming more seriously. Thus information security is emerging as a critical factor in designing a network system and much attention is paid to Network Intrusion Detection System (NIDS), which detects hackers' attacks on network and handles them properly However, the performance of current intrusion detection system cannot catch the increasing rate of the Internet speed because most of the NIDSs are implemented by software. In this paper, we propose a new high performance network intrusion using Network Processor. To achieve fast packet processing and dynamic adaptation of intrusion patterns that are continuously added, a new high performance network intrusion detection system using Intel's network processor, IXP1200, is proposed. Unlike traditional intrusion detection engines, which have been implemented by either software or hardware so far, we design an optimized architecture and algorithms, exploiting the features of network processor. In addition, for more efficient detection engine scheduling, we proposed task allocation methods on multi-processing processors. Through implementation and performance evaluation, we show the proprieties of the proposed approach.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.1
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• pp.78-85
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• 2008

Most researches for power management have focused on increasing the utilization of system performance by scaling operating frequency or operating voltage. If operating frequency is changed frequently, it reduces the real system performance. To reduce power consumption, alternative approaches use the limited number of operating frequencies or set the smoothing frequencies during execution to increase the system performance, but they are not suitable for real time applications. To reduce power consumption and increase system performance for real time applications, this paper proposes a new power-aware schedule method by allocating operating frequencies and by setting smoothing frequencies. The algorithm predicts so that frequencies with continuous interval are mapped into discrete operating frequencies. The frequency smoothing reduces overheads of systems caused by changing operating frequencies frequently as well as power consumption caused by the frequency mismatch at a wide frequency interval. The simulation results show that the proposed algorithm reduces the power consumption up to 40% at maximum and 15% on average compared to the CC RT-DVS.

• Journal of the Korean Operations Research and Management Science Society
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• v.23 no.2
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• pp.187-200
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• 1998

This paper presents an original approach for solving short-term power scheduling in extended power system with two fuels in a unit and a limited fuel using Lagrangian relaxations. The underlying model incorporates the full set of costs and constraints including setup, production, ramping, and operational status, and takes the form of a mixed integer nonlinear control problem. Moreover, the mathematical model developed includes two fuels in a unit and a limited fuel, regulation reserve requirements of prespecified group of units. Lagrangian relaxation is used to disaggregate the model by generator into separate subproblems which are then solved with a nested dynamic program including empirical knowledges. The strength of the methodology lies partially in its ability to construct good feasible solutions from information provided by the dual. Thus, the need for branch-and-bound is eliminated. In addition, the inclusion of two fuels in a unit and a limited fuel provides new insight into the limitations of current techniques. Computational experience with the proposed algorithm indicates that Problems containing up to 23 units including 8 unit used two fuels and 24 time periods can be readily solved in reasonable times. Duality gaps of less than 4％ were achieved.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.711-713
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• 1996

This paper proposes a unit commitment scheduling method based on Genetic Algorithm(GA). Due to a variety of constraints to be satisfied, the search space of the UC problem is highly nonconvex, so the UC problem cannot be solved efficiently only using the standard GA To efficiently deal with the constraints of the problem and greatly reduce the search space of the GA, the minimum up and down time constraints are embedded in the binary strings that are coded to represent the on-off states of the generating units. The violations of other constraints arc handled by integrating penalty factors. To show the effectiveness of the GA based unit commitment scheduling, test results for system of 5 units are compared with results obtained using Lagrangian Relaxation and Dynamic Programming.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.8
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• pp.343-348
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• 2013

We proposes a power-aware fixed-priority real-time scheduling algorithm for multimedia service, called static voltage scaling algorithm with multi-granularity resource reservation (STATIC-MULTIRSV). The multi-granularity resource reservation was introduced to deliver higher system utilization and better temporal isolation than the traditional approaches in [2]. Based on this, our STATIC-MULTIRSV is designed to reduce the power consumptions while guaranteeing that all I-frames of each video stream meet their deadlines. We implemented the proposed algorithm on top of ChronOS Real-time Linux [6]. We experimentally compared STATIC-MULTIRSV with other existing methods which showed that STATIC-MULTIRSV reduce power consumption by maximum 15% compared to its experimental counterparts.