• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.10
• /
• pp.82-94
• /
• 2015

In this paper, we propose hardware prefetch mechanism with an efficient cache replacement policy by giving priority to the trigger block in which a spatial region and producing a spatial region by using the displacement field. It could be taken into account the sequence of the program since a history is based on the trigger block of history record, and it could be quickly prefetching the instructions or data address by adding a stored value to the trigger address and displacement field since a history is stored as a displacement value. Also, we proposed a method of replacing at random by the cache replacement policy from the low priority block when the cache area is full after giving priority to the trigger block. We analyzed using the memory simulator program gem5 and PARSEC benchmark to assess the performance of the hardware prefetcher. As a result, compared to the existing hardware prefecture to generate the spatial region using a bit vector, L1 data cache miss rate was reduced about 44.5% on average and an average of 26.1% of L1 instruction misses occur. In addition, IPC (Instruction Per Cycle) showed an improvement of about 23.7% on average.

• Journal of the Korea Society of Computer and Information
• /
• v.18 no.12
• /
• pp.55-64
• /
• 2013

In this paper, the HILS (Hardware In-the-Loop Simulation) system to analyze and to verify the performance of the targeting pod is addressed. The main functions of the targeting pod is acquiring and tracking targets to guide a LGB (Laser Guided Bomb) to the targets. For the analysis of targeting pod, the real time simulate images generation of IR and daylight cameras, sever control technology, and the analysis of laser transfer characteristics are necessary. For the real time image generation and the laser transfer characteristics analysis, off-the-shelf SDK(Software Development Kit) OKTAL-SE is used. For the servo controller, well-proven mechanism in the previous program is applied to increase servo control accuracy. To analyze the performance of a targeting pod in a realistic environment, 1553B, ARINK818 interface and etc. which are actually implemented in real combat aircrafts are applied in the system. By using the developed HILS system, the performance of currently operating targeting pods in real combat aircrafts can be analyzed and predicted. Additionally, the relationship between overall system performance and each module performance can be analyzed, the currently developed HILS system is expected to be a very useful tool to generate system development requirements of targeting pods and to reduce any possible future development risks.

• KIPS Transactions on Computer and Communication Systems
• /
• v.12 no.1
• /
• pp.9-16
• /
• 2023

Robots are expected to expand their scope of application to the military field and take on important missions such as surveillance and enemy detection in the coming future warfare. Swarm robots can perform tasks that are difficult or time-consuming for a single robot to be performed more efficiently due to the advantage of having multiple robots. Swarm robots require mutual recognition and collaboration. So they send and receive vast amounts of data, making it increasingly difficult to verify SW. Hardware-in-the-loop simulation used to increase the reliability of mission verification enables SW verification of complex swarm robots, but the amount of verification data exchanged between the HILS device and the simulator increases exponentially according to the number of systems to be verified. So communication overload may occur. In this paper, we propose a digital twin-based communication optimization technique to solve the communication overload problem that occurs in mission verification of swarm robots. Under the proposed Digital Twin based Multi HILS Framework, Network DT can efficiently allocate network resources to each robot according to the mission scenario through the Network Controller algorithm, and can satisfy all sensor generation rates required by individual robots participating in the group. In addition, as a result of an experiment on packet loss rate, it was possible to reduce the packet loss rate from 15.7% to 0.2%.

• KIPS Transactions on Software and Data Engineering
• /
• v.12 no.6
• /
• pp.275-284
• /
• 2023

Virtual reality simulations are used for education and training in various fields, and are especially widely used in the medical field recently. The education/training simulator consists of tactile/force feedback generation and image/sound output hardware that provides a sense similar to a doctor's treatment of a real patient using real surgical tools, and software that produces realistic images and tactile feedback. Existing simulators are complicated and expensive because they have to use various types of hardware to simulate various surgical instruments used during surgery. In this paper, we propose a dental surgical simulation system using a force feedback device and a morphable haptic controller. Haptic hardware determines whether the surgical tool collides with the surgical site and provides a sense of resistance and vibration. In particular, haptic controllers that can be deformed, such as length changes and bending, can express various senses felt depending on the shape of various surgical tools. When the user manipulates the haptic feedback device, events such as movement of the haptic feedback device or button clicks are delivered to the simulation system, resulting in interaction between dental surgical tools and oral internal models, and thus haptic feedback is delivered to the haptic feedback device. Using these basic techniques, we provide a realistic training experience of impacted wisdom tooth extraction surgery, a representative dental surgery technique, in a virtual environment represented by sophisticated three-dimensional models.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.10
• /
• pp.4794-4800
• /
• 2012

Many researches have been performed to resist buffer overflow attacks. However, the attack still poses one of the most important issue in system security field. It is because programmers are using library functions containing security hole and once buffer overflow vulnerability has been found, the security patches are distributed after the attacks are widely spreaded. In this paper, we propose a new cache level return address stack architecture for resisting buffer overflow attack. We implemented our hardware onto SimpleScalar simulator and verified its functionality. Our circuit can overcome the various disadvantages of previous works with small overhead.

• Science of Emotion and Sensibility
• /
• v.7 no.3
• /
• pp.27-35
• /
• 2004

This study has investigated a psychological status of optimal and pleasant driving condition by measuring various physiological signals using SCR(skin conductance response), PPG(peripheral plethysmograph), SKT(skin temperature) and HR(heart rate). The physiological response was measured during various simulated driving conditions. We developed a hardware and algorithm to measure and analyze the physiological response. The physiological signals has reflected the level of driver's tension or relaxation as well as the heart rate. The emotional responses of drivers were also measured and analyzed in this experiment. The result of the study can be used to design a system to enhance the driver's emotional satisfaction as well as to monitor the driver's safety and health condition.

• Journal of Power Electronics
• /
• v.14 no.2
• /
• pp.402-412
• /
• 2014

This paper proposes a novel electric propulsion system for naval ships, which consists of Active Front End (AFE) converters directly connected to battery Energy Storage Modules (ESMs). Employing the proposed AFE converters with ESMs in the power systems of naval ships can enhance the reliability and quality of the electric power. Furthermore, the fuel-efficiency of the generator can be improved by a higher loading factor of the generator and its prime movers. The proposed AFE configuration does not require an additional dedicated DC/AC converter for the ESMs. Instead of that, the AFE converter itself can control the DC link voltage and the discharging and/or charging of the ESMs. A control scheme to achieve these control objectives is also presented in this paper. The overall power system, including the generators and electrical loads of a naval ship, is implemented by a small scaled Power Hardware-In-the-Loop (PHIL) simulator. Through this experimental setup, the proposed system configuration and the power control strategies are verified. It is shown that the fuel-efficiency and transient dynamics can be improved in the normal and contingency operation modes.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.59 no.2
• /
• pp.206-211
• /
• 2010

Since high-speed train is a dynamic load in which electric power is externally supplied, contact loss between the catenary and pantograph occurs. This phenomena including vibrations generates frequently irregular arcs, which, in turn causes EMI. Thus it is very important to develop the approach to reduce arc phenomenon by contact loss, as speed of electric railway vehicle increases. In case of an electric railway vehicle using electrical power, compared with diesel rolling stock, Power Line Disturbance(PLD) such as harmonics, transient voltage and current, Electromagnetic Interference(EMI), and dummy signal injection etc usually occur. In this study, the dynamic characteristics of a contact wire and a pantograph suppling electrical power to high-speed train are investigated with an electrical response point. To implement power line disturbance induced by contact loss phenomenon for high speed train operation, a hardware simulator which considers contact loss between contact wire and pantograph as well as contact wire deviation is developed. It is confirmed by the experiments that contact loss effect is largely dependent on voltage conditions when the contact loss occurs. Also, a passive filter is designed to reduce power disturbance and the designed system is verified by experiment.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.16 no.2
• /
• pp.8-17
• /
• 2008

This paper presents the Matlab/Simulink-based software-in-the-loop simulation(SILS) environment which is the co-simulator for temporal and functional simulations of control systems. The temporal behavior of a control system is strongly dependent on the implemented software and hardware such as the real-time operating system, the target CPU, and the communication protocol. The proposed SILS abstracts the system with tasks, task executions, real-time schedulers, and real-time networks close to the implementation. Methods to realize these components in graphical block representations are investigated with Matlab/Simulink, which is most commonly used tool for designing and simulating control algorithms in control engineering. In order to achieve a seamless development from SILS to rapid control prototyping (RCP), the SILS block-set is designed to support automatic code generation without tool changes and block modifications.

• The KIPS Transactions:PartA
• /
• v.12A no.7 s.97
• /
• pp.621-626
• /
• 2005

Recently, flash memory is widely used in various embedded applications since it has many advantages in terms of non-volatility, fast access speed, shock resistance, and low power consumption. However, it requires a software layer called FTL(Flash Translation Layer) due to its hardware characteristics. We present a new FTL algorithm named LSTAFF(Large State Transition Applied Fast flash Translation Layer) which is designed for large block flash memory The presented LSTAFF is adjusted to flash memory with pages which are larger than operating system data sector sizes and we provide performance results based on our implementation of LSTAFF and previous FTL algorithms using a flash simulator.