• Transactions of Materials Processing
• /
• v.16 no.1 s.91
• /
• pp.42-47
• /
• 2007

LCD-BLU is one of kernel parts of LCD and it consists of several optical sheets: LGP, light source and mold frame. The LGP of LCD-BLU is usually manufactured by etching process and forming numerous dots with $50\sim300{\mu}m$ diameter on the surface. But the surface of the etched dots of LGP is very rough due to the characteristics of the etching process during the mold fabrication, so that its light loss is high along with the dispersion of light into the surface. Accordingly, there is a limit in raising the luminance of LCD-BLU. In order to overcome the limit of current etched dot patterned LGP, optical pattern with continuous microlens was designed using optical simulation CAE. Also, a mold with continuous micro-lens was fabricated by UV-LiGA reflow process and applied to 7 inch size of navigator LCD-BLU in the present study.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2014.07a
• /
• pp.1-4
• /
• 2014

인텔 Many Integrated Core (MIC) 아키텍쳐는 61개의 코어가 하나의 칩에 결합되어 있다. Xeon Phi 로 명명된 인텔 MIC는 인텔 E5 Xeon CPU 보다 2배의 single precision GFLOPs 성능을 제공한다. 인텔 MIC 는 수치연산에 최적화 되어 있는 아키텍쳐이다. 우리는 Xeon Phi 7120P를 가지고 벤치마킹을 하였고 클락스피드 1.238GHz, 61Core 이고 한 개의 코어당 4쓰레드를 사용하며 이론상 최고 성능은 Peak Double Precision(GFLOP)는 약 2-TFlops 이다. 이에 우리는 인텔 X86 아키텍쳐에서 openMP 와 인텔 MKL(Math kernel library) 라이브러리를 이용한 병렬프로그램을 작성하여 쓰레드 수를 증가 시키면서 인텔 Xeon Phi 와 E5 Xeon CPU에서 single precision 성능을 벤치마킹 하여, Xeon Phi 와 Xeon E5 의 이론적인 성능을 비교해 보고자 한다. 또한 openMP와 인텔 MKL라이브러리를 사용한 병렬환경에서 CPU의 성능 지표인 클락스피드와 코어수 외에 Vector unit size 의 크기가 성능에 어떤 영향을 미치는지 살펴보았다.

• Proceedings of the KIEE Conference
• /
• 2003.11c
• /
• pp.592-595
• /
• 2003

In this paper, we have designed a Home Networking System using an embedded linux board. The system based on the World-Wide-Web is composed of three parts - a Server, a Client and a Simulator. The Home Networking Server is built in an embedded board using an embedded linux kernel. A web-server and Home Networking Server Seryice Demon programming with a Jaya-Language is included in the board. Clients can connect to the server board using a web-browser in the desktop computer, PDA or any other machines which include a web-browser. For this purpose, we made the client program using a Java-Applet. So, the clients who connect to the server for the control of the applications, download the class-file and execute the client-program in the web-browser. So, the clients don't need any other programs to control the applications from a remote place. The size of server board is very small (86.3$\times$74mm), which makes it very useful not only for the Home-Networking-System but also in many other fields, e.g., embedded robot control system, etc. Using an embedded board instead of a desktop computer is good for a simple network environment and it occupies only a small space to make the system.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.9 no.3
• /
• pp.710-716
• /
• 2008

This paper covers the performance evaluation of two flash memory-based file storages, NAND and NOR, which are the major flash types. To evaluate their performances, we set up separate file storages for the two types of flash memories on a PocketPC-based experimental platform. Using the platform, we measured and compared the I/O throughputs in terms of buffer size, amount of used space, and kernel-level write caching. According to the results from our experiments, the overall performance of the NAND-based storage is higher than that of NOR by up to 4.8 and 5.7 times in write and read throughputs, respectively. The experimental results show the relative strengths and weaknesses of the two schemes and provide insights which we believe assist in the design of flash memory-based file storages.

• Structural Engineering and Mechanics
• /
• v.73 no.5
• /
• pp.585-598
• /
• 2020

We develop design model within which nucleation and propagation of crack in a fibrous composite is described. It is assumed that under loading, crack initiation and fracture of material happens in the composite. The problem of equilibrium of a composite with embryonic crack is reduced to the solution of the system of nonlinear singular integral equations with the Cauchy type kernel. Normal and tangential forces in the crack nucleation zone are determined from the solution of this system of equations. The crack appearance conditions in the composite are formed with regard to criterion of ultimate stretching of the material's bonds. We study the case when near the fiber, the binder has several arbitrary arranged rectilinear prefracture zones and a crack with interfacial bonds. The proposed computational model allows one to obtain the size and location of the zones of damages (prefracture zones) depending on geometric and mechanical characteristics of the fibrous composite and applied external load. Based on the suggested design model that takes into account the existence of damages (the zones of weakened interparticle bonds of the material) and cracks with end zones in the composite, we worked out a method for calculating the parameters of the composite, at which crack nucleation and crack growth occurs.

• Electronics and Telecommunications Trends
• /
• v.33 no.6
• /
• pp.129-138
• /
• 2018

As recent applications are requiring more CPUs for their performance, manycore systems have evolved. Since existing operating systems do not provide performance scalability in manycore systems, Azalea, a multi-kernel based system, has been developed for supporting performance scalability. Unikernel is a new operating system technology starting with the concept of a library OS. Applying unikernel to Azalea enables an improvement in performance. In this paper, we first analyze the current technology trends of unikernel, and then discuss the applications and effects of unikernel to Azalea. Azalea-unikernel was built in a single image consisting of libOS, runtime libraries, and an application, and executed with the desired number of cores and memory size in bare-metal. In particular, it supports source and binary compatibility such that existing linux binaries can be rebuilt and executed in Azalea-unikernel, and already built binaries can be run immediately without modification with a better performance. It not only achieves a performance enhancement, it is also a more secure OS for manycore systems.

• Journal of Korea Multimedia Society
• /
• v.24 no.11
• /
• pp.1552-1559
• /
• 2021

Convolution neural networks (CNNs) show notable performance in image processing and are used as representative core models. CNNs extract and learn features from large amounts of train dataset. In general, it has a structure in which a convolution layer and a fully connected layer are stacked. The core of CNN is the convolution layer. The size of the kernel used for feature extraction and the number that affect the depth of the feature map determine the amount of weight parameters of the CNN that can be learned. These parameters are the main causes of increasing the computational complexity and memory usage of the entire neural network. The most computationally expensive components in CNNs are fully connected and spatial convolution computations. In this paper, we propose a Fourier Convolution Neural Network that performs the operation of the convolution layer in the Fourier domain. We work on modifying and improving the amount of computation by applying the fast fourier transform method. Using the MNIST dataset, the performance was similar to that of the general CNN in terms of accuracy. In terms of operation speed, 7.2% faster operation speed was achieved. An average of 19% faster speed was achieved in experiments using 1024x1024 images and various sizes of kernels.

• Nuclear Engineering and Technology
• /
• v.55 no.9
• /
• pp.3367-3382
• /
• 2023

Smoothed Particle Hydrodynamics (SPH) is a Lagrangian computational fluid dynamics method that has been widely used in the analysis of physical phenomena characterized by large deformation or multi-phase flow analysis, including free surface. Despite the recent implementation of eddy-viscosity models in SPH methodology, sophisticated turbulent analysis using Lagrangian methodology has been limited due to the lack of computational performance and numerical consistency. In this study, we implement the standard and dynamic Smagorinsky model and dynamic Vreman model as sub-particle scale models based on a weakly compressible SPH solver. The large eddy simulation method is numerically identical to the spatial discretization method of smoothed particle dynamics, enabling the intuitive implementation of the turbulence model. Furthermore, there is no additional filtering process required for physical variables since the sub-grid scale filtering is inherently processed in the kernel interpolation. We simulate lid-driven flow under transition and turbulent conditions as a benchmark. The simulation results show that the dynamic Vreman model produces consistent results with experimental and numerical research regarding Reynolds averaged physical quantities and flow structure. Spectral analysis also confirms that it is possible to analyze turbulent eddies with a smaller length scale using the dynamic Vreman model with the same particle size.

• Journal of Drive and Control
• /
• v.20 no.4
• /
• pp.133-139
• /
• 2023

A weighing system calculates the bucket's excavation amount of an excavator. Usually, the excavation amount is computed by the excavator's motion equations with sensing data. But these motion equations have computing errors that are induced by assumptions to the linear systems and identification of the equation's parameters. To reduce computing errors, some commercial weighing system incorporates particular motion into the excavation process. This study introduces a linear regression model on an artificial neural network that has fewer predicted errors and doesn't need a particular pose during an excavation. Time serial data were gathered from a 30tons excavator's loading test. Then these data were preprocessed to be adjusted by MPL (Multi Layer Perceptron) or CNN (Convolutional Neural Network) based linear regression models. Each model was trained by changing hyperparameter such as layer or node numbers, drop-out rate, and kernel size. Finally ID-CNN-based linear regression model was selected.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2008.05a
• /
• pp.641-644
• /
• 2008

This paper describes the GUI implementation of an intelligent embedded system which can be used for a personal information platform and an industrial mobile application system. It shows the architecture and the necessary structure and components of X Window graphic system. The embedded system used in this paper has low power and high performance processor, and has a large memory size with a nand-flash memory device. We configured the linux kernel with a TIT-LCD and touch screen device for the operation of X Window system. And we used GTK+2 for running application softwares on the platform embedded system. The GUI library of GTK+2 is useful for providing the same graphics programming environment with host Linux PC. We have developed in this paper the X Window system and the GUI environment for GTK+2 in a new embedded system, and verified the full operation of X Window system and application softwares using GTK+2. The embedded system with large memory size can be used in X Window application softwares for providing a personal information service with a mobile embedded system.