• Journal of the Semiconductor & Display Technology
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• v.23 no.3
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• pp.1-6
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• 2024

Recent research on embedded systems has become increasingly important due to their central role in high-performance embedded devices, including artificial intelligence, autonomous driving, and energy management technologies. Embedded systems are specialized computer systems designed to perform specific tasks while optimizing performance and minimizing memory usage. RISC-V, an open RISC-based instruction set architecture developed by the University of Berkeley in 2010, is well-suited for these systems. In addition to the base 32-bit integer instruction set, RISC-V supports extensions such as the M-extension for multiplication and division and the C-extension for instruction compression. In this paper, we propose the design of a 32-bit 5-stage pipeline RV32IMC processor aimed at high-performance embedded devices. By incorporating the RV32IMC instruction set, the proposed processor achieves enhanced computational efficiency and reduced code size, making it a strong candidate for energy-efficient, high-performance embedded applications. Furthermore, the design was validated on an Artix-7 field-programmable gate array, demonstrating the processor's feasibility and potential benefits for embedded systems.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.9
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• pp.1305-1310
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• 2010

In a practical design process, the method of extracting the design space information of the complex system for verifying, improving, and optimizing the design process by taking into account the design variables and their shape tolerance is very important. Finite element analysis has been successfully implemented and integrated with design of experiment such as D-Optimal array; thus, a response surface model and optimization tools have been obtained, and design variables can be optimized by using the model and these tools. Then, to guarantee the robustness of the design variables, a robust design should be additionally performed by taking into account the statistical variation of the shape tolerance of the optimized design variables. In this study, a new approach based on the use of the response surface model is proposed; in this approach, the standard normal distribution of the shape tolerance is considered. By adopting this approach, it is possible to simultaneously optimize variables and perform a robust design. This approach can serve as a means of efficiently modeling the trade-off among many conflicting goals in the applications of finite element analysis. A case study on the robust optimal design of disc brakes under thermal loadings was carried out to solve multiple objective functions and determine the constraints of the design variables, such as a thermal deformation and weight.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.5_6
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• pp.268-278
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• 2004

In this paper, we describe our experience in the design and implementation of the SMART file system to handle multimedia workload. Our work has three design objectives: (ⅰ) efficient support for sequential workload, (ⅱ) avoiding disk fragmentation, (ⅲ) logical unit based file access. To achieve these three objectives, we develop a file system where a file consists of linked list of Data Unit Group. Instead of tree like structure of the legacy Unix file system, we use single level file structure. Our file system can also access the file based upon the logical unit which can be video frame or audio samples. Data Unit Group is a group of logical data units which is allocated continuous disk blocks. At the beginning of each Data Unit Group, there exists an index array. Each index points to the beginning of logical data units, e.g. frames in the Data Unit Group. This index array enables the random access and sequencial access of semantic data units. SMART file system is elaborately tailored to effectively support multimedia workload. We perform physical experiments and compare the performance of SMART file system with EXT2 file system and SGI XFS file system. In this experiment, SMART file system exhibits superior performance under streaming workload.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.8
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• pp.624-631
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• 2018

To meet the requirements of various satellite synthetic aperture radar(SAR) system performance parameters, the characteristics of the antenna pattern should be analyzed. In this paper, we propose a method to improve the SAR system performance using an effective technique for optimizing antenna pattern synthesis in the presence of element failure. The desired antenna pattern can be synthesized by referring to the optimized antenna mask templates using the particle swarm optimization algorithm. In the simulation, the performance of the proposed method is verified by analyzing characteristics related to the SAR system performance parameters using antenna pattern regeneration.

• YAKHAK HOEJI
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• v.57 no.3
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• pp.187-193
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• 2013

Bojungikgi-tang has been widely used for enhancement of physical fitness in Korea. The convenient, simple, and accurate high-performance liquid chromatography (HPLC) method was established for simultaneous determination of four marker compounds, liquiritin, nodakenin, hesperidin, and glycyrrhizin in Bojungikgi-tang (Buzhongyiqi-tang in Chinese, Hochuekkito in Japanese), a traditional Korean herbal prescription. The column for optimizing HPLC separation was used a Gemini $C_{18}$ column at column oven temperature of $40^{\circ}C$ with 1.0% (v/v) aqueous acetic acid (A) and 1.0% (v/v) acetic acid in acetonitirle (B) by gradient flow. The flow rate was 1.0 ml/min and the detector was a photodiode array (PDA) set at 254 nm, 280 nm, and 335 nm. Calibration curves of four components were acquired with $r^2$ values ${\geq}0.9999$. The recoveries were found to range 92.11~105.68% with relative standard deviations (RSDs, %) value less than 2.50%. The RSD values of intraand inter-day precision were 0.07~2.50% and 0.16~1.99%, respectively. The contents of liquiritin, nodakenin, hesperidin and glycyrrhizin in Bojungikgi-tang were 3.85~3.92 mg/g, 2.27~2.32 mg/g, 4.14~4.19 mg/g, and 3.39~3.45 mg/g, respectively. The established simultaneous analysis method will be effective for quality control of Bojungikgi-tang.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.2
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• pp.265-273
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• 2000

In relational database management systems(RDBMS), a table consIn relational database management systems(RDBMS), a table consists of sets of records which are composed of a set of attributes. The number of distinct values(NDV) of an attribute denotes the number of distinct attribute values that actually appear in the database records, and is widely used in optimizing queries and supporting statistic queries. Object-relational database management systems(ORBBMSS), however, support the inheritance between tables which enforces an attribute defined in a super-table to be inherited in sub-tables automatically. Hence, in ORDBMSS, not only NDV of an attribute In a single table but also NDV of an attribute in multiple tables(HNDV) is needed. In this paper, we propose a method that calculates HNDV using arrays of attribute value intervals. In this method, an array of attribute value intervals is created for an attribute of interest In each table in a table hierarchy, and HNDV can be calculated or estimated by merging the arrays of attribute value intervals. The proposed method accurately calculates HNDV using small additional storage space and is efficient for an environment where only some of the tables in a table hierarchy are frequently updated.

• Korean Journal of Pharmacognosy
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• v.43 no.1
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• pp.10-15
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• 2012

An accurate and sensitive analysis method was established for simultaneous determination of three bioactive compounds (glycyrrhizin, 6-gingerol and ginsenoside Rg3) in the Ejung Tang with high-performance liquid chromatography (HPLC)-photodiode array detection (DAD)-electrospray ionization (ESI)-Mass spectrometry (MS). The optimizing chromatographic separations a were acquired by an $C_{18}$ column ($5{\mu}m$, $4.6I.D{\times}250mm$, SHISHEDO) using gradient elution with water comprising 0.1% TFA(trifluoroacetic acid) and acetonitrile at a performing temperature of $35^{\circ}C$. Flow rate was 1.0 ml/min. A detection UV wavelength set at 205 nm and 250 nm. The three compounds were identified by electrospray ionization mass spectrometry. All calibration curves indicated great linear regression within test ranges ($R^2>0.9997$). The established method provided acceptable precision and accuracy. The relative standard deviations (RSDs) of intra-day and inter-day were less than 2.00% and 3.00%, respectively. The recoveries were found to range from 94.49 to 101.10% for the three compounds analyzed. These results showed that this method was effective and reliable for quality control of Eiung-Tang.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.1
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• pp.20-26
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• 2021

Recent systems contain hardware and software components together for faster execution speed and less power consumption. In conventional hardware and software co-design, the ratio of software and hardware was divided by the designer's empirical knowledge. To find optimal results, designers iteratively reconfigure accelerators and applications and simulate it. Simulating iteratively while making design change is time-consuming. In this paper, we propose a hardware and software co-design platform for energy-efficient FPGA accelerator design. The proposed platform makes it easy for designers to find an appropriate hardware ratio by automatically generating application program code and hardware code by parameterizing the components of the accelerator. The co-design platform based on the Vitis unified software platform runs on a server with Xilinx Alveo U200 FPGA card. As a result of optimizing the multiplication accelerator for two matrices with 1000 rows, execution time was reduced by 90.7% and power consumption was reduced by 56.3%.

• Journal of the Semiconductor & Display Technology
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• v.20 no.4
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• pp.29-37
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• 2021

A 7 nm technology node using extreme ultraviolet lithography with a wavelength of 13.5 nm has been recently developed and applied to the semiconductor manufacturing process. Furthermore, the development of sub-3 nm technology nodes continues to be required. In this study, design factors of an electrostatic deflector for an ultra-miniaturized microcolumn system that can realize an electron wavelength of below 1.23 nm with an acceleration voltage of above 1 eV were investigated using a three-dimensional simulator. Particularly, the optimal design of the electrostatic octupole floating deflector was derived by optimizing the design elements and improving the driving method of the 1 keV low energy ultra-miniaturized microcolumn deflector. As a result, the entire wide field of view greater than 330 ㎛ at a working distance of 4 mm was realized with an ultra-high-resolution electron beam spot smaller than 10 nm. The results of this study are expected to be a basis technology for realizing a wafer-scale multi-array microcolumn system, which is expected to innovatively improve the throughput per unit time, which is the biggest drawback of electron beam lithography.

• Land and Housing Review
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• v.15 no.1
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• pp.57-75
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• 2024

To create dynamic and bustling urban environments, a diverse array of commercial facilities is indispensable. These facilities are recognised as pivotal in attracting and accommodating a larger floating population, thereby suggesting that a greater diversity of commercial establishments fosters heightened consumer expenditure. With this premise, our study endeavours to explore the influence of commercial facility diversity on the Consumer Centre Index. Focused on the temporal context of 2021 and the spatial context of Seoul, our analysis utilizes the Consumer Centre Index, derived from Kernel Density analysis, as the dependent variable. Independent variables encompass factors reflecting commercial attributes and urban characteristics. Employing spatial regression analysis at the administrative district level, we discern that the clustering of similar industries exerts a more pronounced positive effect on consumer activation compared to the clustering of disparate industries. Additionally, the findings underscore the importance of concentrating industries that bolster consumer activation. Anticipated outcomes of this study include insights beneficial for optimizing commercial facility location policies within the consumer market.