• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37C no.11
• /
• pp.1170-1181
• /
• 2012

Wireless Sensor Networks(WSNs) are used in diverse applications. In general, sensor nodes that are easily deployed on specific areas have many resource constrains such as battery power, memory sizes, MCUs, RFs and so on. Hence, first of all, the efficient energy consumption is strongly required in WSNs. In terms of event states, event-driven deliverly model (i.e. surveillance and reconnaissance applications) has several characteristics. On the basis of such a model, clustering algorithms can be mostly used to manage sensor nodes' energy efficiently owing to the advantages of data aggregations. Since a specific node collects packets from its child nodes in a network topology and aggregates them into one packet to relay them once, amount of transmitted packets to a sink node can be reduced. However, most clustering algorithms have been designed without considering can be reduced. However, most clustering algorithms have been designed without considering characteristics of event-driven deliverly model, which results in some problems. In this paper, we propose enhanced clustering algorithms regarding with both targets' movement and energy efficiency in order for applications of surveillance and reconnaissance. These algorithms form some clusters to contend locally between nodes, which have already detected certain targets, by using a method which called CHEW (Cluster Head Election Window). Therefore, our proposed algorithms enable to reduce not only the cost of cluster maintenance, but also energy consumption. In conclusion, we analyze traces of the clusters' movements according to targets' locations, evaluate the traces' results and we compare our algorithms with others through simulations. Finally, we verify our algorithms use power energy efficiently.

• Journal of information and communication convergence engineering
• /
• v.9 no.2
• /
• pp.177-182
• /
• 2011

Considerations for user-centric environments are regarded as essential for the successful deployment of convergence services in BcN. Event driven service (EDS) is regarded as a typical convergence service converging different functions of multiple service providers to support user-centric environments. This paper first describes the deployment model and service scenario of EDS, a convergence service for user-centric environments in BcN. The user-centric environments stimulates the unified identifier management, namely unified identification (U-ID), to enable users to be provided convergence services without awareness of multiple providers. Then the designed structure and implementation results are given.

• Journal of information and communication convergence engineering
• /
• v.8 no.5
• /
• pp.502-507
• /
• 2010

Event driven service (EDS) is one of such services administrating different functions of multiple service providers according to the user situation. This paper first describes the service model of EDS, a User-centric Service for multiple service provider environments over the next generation networks. The multiple provider environments stimulates the unified identifier management, namely unified identification (U-ID), to enable users to be provided network services without awareness of multiple providers. Combining these two concepts, i.e., EDS and U-ID, the designed structure of EDS with U-ID and related procedures are given. Finally, the implementation results tested on Korea Advanced Research Network (KOREN) are described.

• Journal of KIISE:Software and Applications
• /
• v.28 no.12
• /
• pp.921-929
• /
• 2001

OCL was used in the UML Semantics document to specify the well-formedness rules of the UML metarmodel. UML was extended to apply it to system developments of several fields, for example real-time UML and web applications with UML. In particular the dependability is important in designing and building hard real-time system. Thus OCL is needed to express real-time UML formally and so it must extended. In this paper, we extend OCL to define event-driven real-time OCL to the development of Nrcl simulator.

• KIPS Transactions on Computer and Communication Systems
• /
• v.3 no.3
• /
• pp.73-80
• /
• 2014

In this paper, we propose an incremental simulation method in event-driven HDL simulation to reduce the simulation execution time. In general, the simulation is repeated with a series of design changes. Incremental simulation is an efficient simulation method that shortens the simulation execution time for the following simulation by using the result of previous simulation. We have observed the effectiveness of the proposed approach through the experimentation with multiple real designs.

• Journal of the Society of Naval Architects of Korea
• /
• v.34 no.1
• /
• pp.111-121
• /
• 1997

This paper is aimed to prose a welding information system which is usable for ship design and production processes. For this work, the welding information related to shipbuilding is analyzed systematically. Database system and object-oriented paradigm are integrated to describe the welding information model of ship structure. Event-driven programming technique and graphical user interface are used to provide the richer interactive environment and the flexibility for the application. Test program is developed to verify the consistency of the created model and to see the effectiveness of the used programming technique.

• Journal of KIISE
• /
• v.44 no.5
• /
• pp.449-459
• /
• 2017

Data Distribution Service (DDS) is a communication middleware that supports a flexible, scalable and real-time communication capability. This paper describes several techniques to improve the performance of DDS middleware. Detailed events for the internal behavior of the middleware are defined. A DDS message is disassembled into several submessages of independent, meaningful units for event-driven structuring in order to reduce the processing complexity. The proposed technique of history cache management is also described. It utilizes the fact that status access and random access to the history cache occur more frequently in the DDS. These methods have been implemented in the EchoDDS, the DDS implementation developed by our team, and it showed improved performance.

• Journal of National Security and Military Science
• /
• s.3
• /
• pp.197-242
• /
• 2005

Active catalog is a kind of digital content that enables consumers to test the functions and features of products from their PCs as if they were using it in real life, by simulating the actions and responses of the product. This new type of interactive digital content can be used extensively to make sales personnel training manuals, sales tools, user manuals and user trouble shooting documents. With active catalogs, companies will be able to compare different designs, show actions according to different functions, and evaluate user reaction to new products without having to produce a single physical prototype or mock-up. At the same time, consumers will be able to understand and 'operate' the product and make well-informed purchase decisions. In this paper, we present a visual event-driven modeling tool, PlayMo, for creating active catalogs, analyze the advantages of using PlayMo, describe the event-driven method used by PlayMo and also introduce two enhanced characteristics of the Event Flow Chart with which the events in PlayMo are structured. Interactive digital content by using the PlayMo3D makes easy, simple and effective design for e-learning, e-catalogue, e-marketing/sales, e-prototyping, customer support, etc. Through its application-ready 3D function visualization solution, engineers and designers can rapidly turn a CAD design model into a 3D interactive virtual product, and the effective function prototyping job can be also completed within a minute.

• Journal of KIISE:Computing Practices and Letters
• /
• v.15 no.2
• /
• pp.89-97
• /
• 2009

Embedded systems widely used in ubiquitous environments usually employ an event-driven programming model instead of thread-based programming model in order to create a more robust system that uses less memory. However, as the software for embedded systems becomes more complex, it becomes hard to program as a single event handler using the event-driven programming model. This paper discusses the implementation of non-preemptive real-time scheduling theory for the design of embedded systems. To this end, we present an efficient schedulability test method for a given non-preemptive task set using a sufficient condition. This paper also shows that the notion of sub-tasks in embedded systems can overcome the problem of low utilization that is a main drawback of non-preemptive scheduling.

• Journal of the Korea Society of Computer and Information
• /
• v.26 no.8
• /
• pp.1-11
• /
• 2021

This paper proposes a novel mechanism called Event-driven Uncore Frequency Scaler (eUFS) to improve the energy efficiency of the HPC systems. UFS exploits the hardware events such as LAPI (Last-level Cache Accesses Per Instructions) and CPI (Clock Cycles Per Instruction) to dynamically adjusts the uncore frequency. Hardware events are collected at a reference time period, and the target uncore frequency is determined using the collected event and the previous uncore frequency. Experiments with the NPB benchmarks demonstrate that the eUFS reduces the energy consumption by 6% on average for class C and D NPB benchmarks while it only increases the execution time by 2% on average.