• The Journal of the Korea Contents Association
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• v.4 no.2
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• pp.50-60
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• 2004

Recently, most of the embedded system is required not only many functions but also real-time characteristics in purpose. In the hard real-time system, especially, strict deadline of periodic task can affect the performance of the system. In this paper, we design and implement the scheduler based on RM(Rate-Monotonic) rule. This scheduler makes feasible patterns based on EDF(Earliest deadline first) rule with extended schedulability inspection before execution, for periodic task-set that has high CPU utilization and then, execute periodic task-set depended on feasible patterns. The feasible pattern formed into EDF rule is capable of the efficiency of CPU up to 100 percentage and by the referenced execution of the feasible pattern is possible of removing the red-time scheduling overhead that is the defect of the order of dynamic assignment rule.

• Journal of the Korea Society of Computer and Information
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• v.13 no.4
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• pp.1-9
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• 2008

Most consumer electronics companies hold numerous line-ups to cope with divergent customer's needs. To cope with current situation, most products are derived from the 'base product' which is developed for brand new features with respect to the change requests. That is called derivation. After 'base code' is developed for newly introduced products, some modification will occur corresponding to the derivative product models. So, quality attributes of 'base code' affects quality and productivity of 'derived code'. But in the middle of continuous modification to 'base code', violation of architectural design decision and unauthorized or maybe unsophisticated change to source code willing to happen and thus it cause critical problem. Those code has 'aging symptom' both architectural and code level in nature. In this paper, we introduced reengineering framework which guide the procedure and tactics to find and fix 'aging symptom' for improvement on quality attribute of 'base code'.

• Smart Structures and Systems
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• v.6 no.3
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• pp.183-196
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• 2010

Monitoring and economical design of alternative energy generators such as wind turbines is becoming increasingly critical; however acquisition of the dynamic output data can be a time-consuming and costly process. In recent years, low-cost wireless sensors have emerged as an enabling technology for structural monitoring applications. In this study, wireless sensor networks are installed in three operational turbines in order to demonstrate their efficacy in this unique operational environment. The objectives of the first installation are to verify that vibrational (acceleration) data can be collected and transmitted within a turbine tower and that it is comparable to data collected using a traditional tethered system. In the second instrumentation, the wireless network includes strain gauges at the base of the structure. Also, data is collected regarding the performance of the wireless communication channels within the tower. In both turbines, collected wireless sensor data is used for off-line, output-only modal analysis of the ambiently (wind) excited turbine towers. The final installation is on a turbine with embedded braking capabilities within the nacelle to generate an "impulse-like" load at the top of the tower. This ability to apply such a load improves the modal analysis results obtained in cases where ambient excitation fails to be sufficiently broad-band or white. The improved loading allows for computation of true mode shapes, a necessary precursor to many conditional monitoring techniques.

• Journal of the Korean Society for Railway
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• v.18 no.3
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• pp.212-222
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• 2015

The characteristics of noise emission from tram systems should be investigated in order to design and construct an urban tram network that raises fewer environmental noise problems. In this paper, the characteristics of rolling noise from a tram were studied and a desired stiffness of the rail supports was proposed using a noise prediction model. The mobilities of embedded rails and resilient wheels were predicted using the Timoshenko beam model and the finite element model, respectively. The predicted mobilities were compared with the measured results. Compared with the measured values, the calculated noise level near the track showed small errors for frequencies higher than 300 Hz. Then, the source strengths of rail and wheel components were examined by varying the rail supporting stiffness and the slab supporting stiffness so that suitable stiffness values could be estimated that would reduce noise radiated from rails and wheels but that would not greatly increase the ground vibration.

• The Journal of the Acoustical Society of Korea
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• v.32 no.2
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• pp.157-166
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• 2013

This paper proposes a non-intrusive speech quality estimation method considering the effects of packet loss to perceptual quality. Packet loss is a major reason of quality degradation in a packet based speech communications network, whose effects are different according to the input speech characteristics or the performance of the embedded packet loss concealment (PLC) algorithm. For the quality estimation system that involves packet loss effects, we first observe the packet loss of G.729 codec which is one of narrowband codec in VoIP system. In order to quantify the lost packet affects, we design a classification algorithm only using speech parameters of G.729 decoder. Then, the degradation values of each class are iteratively selected that maximizes the correlation with the degradation PESQ-LQ scores, and total quality degradation is modeled by the weighted sum. From analyzing the correlation measures, we obtained correlation values of 0.8950 for the intrusive model and 0.8911 for the non-intrusive method.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.1
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• pp.81-89
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• 2012

This study propose the vibration-based damage monitoring scheme for steel girder bolt-connection member by using wireless acceleration sensor node. In order to achieve the objective, the following approaches are implemented. Firstly, wireless acceleration sensor node is described on the design of hardware components and embedded operation software. Secondly, the vibration-based damage monitoring scheme of the steel girder bolt-connection member is described. The damage monitoring scheme performed global damage occurrence alarming and damage localization estimation by the acceleration response feature analysis. The global damage alarming is applied to the correlation coefficient of power spectral density. The damage localization estimation is applied to the frequency-based damage detection technique and the mode-shape-based damage detection technique. Finally, the performance of the vibration-based damage monitoring scheme is evaluated for detecting the bolt-connection member damage on a lab-scale steel girder.

• Proceedings of the IEEK Conference
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• summer
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• pp.410-415
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• 2004

Employing knowledge of adaptive possibilities of agents in multi-agents system, we have explored new aspects of distributed modular systems for building ubiquitous heterogeneous robotic systems using intelligent building blocks (I-BLOCKS) [1] as reconfigurable modules. This paper describes early technological approaches related to technical design, experimental developments and evaluation of adaptive processing and information interaction among I-BLOCKS allowing users to easily develop modular robotic systems. The processing technology presented in this paper is embedded inside each $DUPLO^1$ brick by microprocessor as well as selected sensors and actuators in addition. Behaviors of an I-BLOCKS modular structure are defined by the internal processing functionality of each I-Block in such structure and communication capacities between I-BLOCKS. Users of the I-BLOCKS system can easily do 'programming by building' and thereby create specific functionalities of a modular robotic structure of intelligent artefacts without the need to learn and use traditional programming language. From investigating different effects of modern artificial intelligence, I-BLOCKS we have developed might possibly contain potential possibilities for developing modular robotic system with different types of morphology, functionality and behavior. To assess these potential I-BLOCKS possibilities, the paper presents a limited range of different experimental scenarios in which I-BLOCKS have been used to set-up reconfigurable modular robots. The paper also reports briefly about earlier experiments of I-BLOCKS created on users' natural inspiration by a just defined concept of modular artefacts.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.283-294
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• 2012

Recently increasing usage of smart phones so, the application field of convergence industry between IT technology using smart phone-based mobile communication networks and other industry branches is expanding. In addition, R&D technologies in other fields are applied to smart phone applications effectively in order to develop products and support daily life more convenient. However, it is very hard to control these products and there is no efficient solution for this problem when many people are sent to specific area for big events, such as Biennale, Film Festival, EXPO, and so on. In order to solve this problem, this paper describes a network-based ticket reservation system and its organization using augmented reality on smart phone and mobile communication networks. In particular, we propose a method of designing and developing prototyping system based on smart phone application design technologies, prior to developing real smart phone application.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.4
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• pp.135-141
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• 2020

Today, CPUs in general-purpose computers such as servers, desktops and laptops, as well as home appliances and embedded systems, consist mostly of multicore processors. In order to improve performance, it is required to use an out-of-order execution processor by Tomasulo algorithm as each core processor. An out-of-order execution processor with Tomasulo algorithm can execute the available instructions in any order and perform speculation in order to reduce control dependencies. Therefore, the performance of an out-of-order execution processor can be significantly improved compared to an in-order execution processor. In this paper, an out-of-order execution processor using Tomasulo algorithm and ARM instruction set is designed using VHDL record data types and simulated by GHDL. As a result, it is possible to successfully perform operations on programs written in ARM instructions.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.4 s.316
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• pp.79-88
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• 2007

Demand for the technology for access to device control network in industry and for access to building automation system via internet is on the increase. In such technology integration of a device control network with a data network such as internet and organizing wide-ranging DCS(distributed control system) is needed, and it can be realized in the framework of VDN(virtual device network)[1,2]. Specifications for device control network and data network are quite different because of the differences in application. So a router that translates the communication protocol between device control network and data network and efficiently transmits information to destination is needed for implementation of the VDN, This paper proposes the concept of NCS(networked control system) based on VDN(virtual device network) and suggests the routing algorithm that uses embedded system.[3]