• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.4C
• /
• pp.247-252
• /
• 2005

Currently, the decoder receives a 16 bit channel input and restores an 8 bit data symbol in the DVD system. Such modulation code of DVD is the EFMplus code, and it is composed of a main table and a sub table. For reducing the size of the code table, this paper divided the code table into 3 groups and we implemented the decoder using this new code table. After all, this method enables us to reduce the size of ROM as reducing the total number of code from 1376 to 750.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.18 no.5
• /
• pp.611-616
• /
• 2008

Error correcting codes (ECCs) are commonly used to protect against the soft errors. Single error correcting and double error detecting (SEC-DED) codes are generally used for this purpose. The proposed approach in this paper selectively reduced power consumption, delay, and area in single-error correcting, double error-detecting checker circuits that perform memory error correction. The multi-objective genetic algorithm is employed to solve the non -linear optimization problem. The proposed method allows that user can choose one of different non-dominated solutions depending on which consideration is important among them. Because we use multi-objective genetic algorithm, we can find various dominated solutions. Therefore, we can choose the ECC according to the important factor of the power, delay and area. The method is applied to odd-column weight Hsiao code which is well- known ECC code and experiments were performed to show the performance of the proposed method.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.24 no.10B
• /
• pp.1824-1831
• /
• 1999

In this paper, the data recovery performance of systematic erasure codes in burst loss environments is analyzed and the estimation method of redundant data according to loss characteristics is suggested. The burstness of packet loss is modeled by Gilbert model, and the performance of proposed packet loss recovery method in the case of using systematic erasure code is analyzed based on previous study on the loss recovery in the case of using erasure code. The required redundancy data fitting method for systematic erasure code in the condition of given loss property is suggested in the consideration of packet loss characteristics such as average packet loss rate and average loss length.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.3C
• /
• pp.69-76
• /
• 2005

In this paper, we propose a biorthogonal modulation employing a constant-amplitude transmission of multi-code signals by introducing a simple constant-amplitude coding scheme with redundant bits. The proposed constant-amplitude biorthogonal multi-code (CABM) modulation can provide high spectral efficiency compared with a conventional direct sequence/spread spectrum (DS/SS) modulation. Nevertheless the proposed CABM modulation can keep up a constant-amplitude signal. Additionally, we propose various types of demodulation structures for the CABM modulation. Simulation results show that bit error rate (BER) performance and hardware complexity of the proposed CABM modulation are highly improved in comparison with those of a constant-amplitude orthogonal multi-code (CAOM) modulation.

• Journal of Electrical Engineering and Technology
• /
• v.10 no.4
• /
• pp.1408-1414
• /
• 2015

The renewable energies such as photovoltaic power, wind power and biomass have grown to a greater extent as decarbonization techniques. The renewable energies are interconnected to power systems (or electrical grids) in order to increase benefits from economies of scale, and the extra attention is focused on the Grid Code. A grid code defines technical parameters that power plants must meet to ensure functions of power systems, and the grid code determined by considering power system characteristics is various across the country. Some TSO (Transmission System Operator) and ISO (Independent System Operator) have issued grid code for wind power and the special requirements for offshore wind farm. The main purpose of the above grid code is that wind farm in power systems has to act as the existing power plants. Therefore wind farm developer and wind turbine manufacturer have great difficulty in grasping and meeting grid code requirements. This paper presents the basic understanding for grid codes of developed countries in the wind power and trends of those technical requirements. Moreover, in grid code viewpoint, the active power control of wind power is also discussed in details.

• Earthquakes and Structures
• /
• v.8 no.5
• /
• pp.977-994
• /
• 2015

In this study, earthquake loads are investigated statistically and compared with the nominal earthquake loads calculated according to the Turkish Earthquake Code, namely: "Specifications for Structures to be Built in Earthquake Areas". For this purpose, the "actual" mean load values estimated from statistical methods and the nominal load values computed according the Seismic Code are compared, with respect to some variations in the basic parameters, such as the importance factor, building height, site coefficient, seismic zone and seismic load reduction factor. In addition to the data compiled from different regions of Turkey, the published data and information in the foreign literature are also used in the determination of the earthquake load statistics. Although the dead and live loads acting on a structure are independent of the geographical location of the structure, environmental loads, such as earthquake loads are highly dependent on the location of the structure. Accordingly, for the assessment of statistical parameters associated with earthquake loads, twelve different locations which can represent the different seismic zones of Turkey as accurately as possible are chosen. As a result of the code calibration procedure considered in this study, it is observed that the load values obtained from the Turkish Seismic Code may overestimate or underestimate the actual seismic loads in some of the seismic zones.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.6A
• /
• pp.631-639
• /
• 2004

In this paper, we presented a new interference suppression method based on code grouping and groupwise decorrelation for multirate DS-CDMA downlink. The code grouping is accomplished according to the correlation property between the mother code and the child codes in OVSF code tree. Using groupwise decorrelation, the proposed receiver has relatively low computational complexity and does not require any information about interference users, such as code, data, and amplitude. From the simulation results in multipath channels, the proposed receiver is to provide significant performance enhancement.

• Nuclear Engineering and Technology
• /
• v.52 no.8
• /
• pp.1603-1610
• /
• 2020

Due to ever-growing advancements in computers and relatively easy access to them, many efforts have been made to develop high-fidelity, high-performance, multi-physics tools, which play a crucial role in the design and operation of nuclear reactors. For this purpose in this study, the neutronic Monte Carlo and thermal-hydraulic sub-channel codes entitled MCNP and COBRA-EN, respectively, were applied for external coupling with each other. The coupled code was validated by code-to-code comparison with the internal couplings between MCNP5 and SUBCHANFLOW as well as MCNP6 and CTF. The simulation results of all code systems were in good agreement with each other. Then, as the second problem, the core of the VVER-1000 v446 reactor was simulated by the MCNP4C/COBRA-EN coupled code to measure the capability of the developed code to calculate the neutronic and thermohydraulic parameters of real and industrial cases. The simulation results of VVER-1000 core were compared with FSAR and another numerical solution of this benchmark. The obtained results showed that the ability of the MCNP4C/COBRA-EN code for estimating the neutronic and thermohydraulic parameters was very satisfactory.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.18 no.1
• /
• pp.83-91
• /
• 1993

In the digital transmission system, cyclic redundancy check(CRC) code is widely used because it is easy to be implemented and has good performance in error detection. CRC code generator consists of several shift registers and modulo 2 adders. After manipulation of input data stream in the encoder, the remaining value of shift registers becomes CRC code. At the receiving side, error can be detected and corrected by CRC codes immediately transmitted after data stream. But, in the high speed system such as an A TM switch, it is difficult to implement the serial CRC encoder because of speed limitation of available semiconductor devices. In this paper, we propose the efficient parallel CRC encoder and syndrome calculator to solve the speed problem in implementing these functions using the existing semiconductor technology.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.39 no.4
• /
• pp.1-9
• /
• 2002

The various researches are investigated for translating Bytecode into native code which can be implemented in the specific processor using classical compiling methods to improve the execution speed of the Java application programs. The code generation techniques using pattern matching can generate more high-quality machine code than code expansion techniques. We provide, in this research, the standardized pattern describing methods and pattern matching techniques that can be used to generate the register-based intermediate code which is for the effective native code generation from Bytecode. And we designed and realized the intermediate code translator with which we can generate the high-quality register-based intermediate code using standardized pattern described formerly.