• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.798-801
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• 2010

This paper describes an efficient architecture for LDPC(Low-Density Parity Check) decoder, which supports three block lengths (648, 1,296, 1,944) of IEEE 802.11n standard. To minimize hardware complexity, the min-sum algorithm and block-serial layered structure are adopted in DFU(Decoding Function Unit) which is a main functional block in LDPC decoder. The optimized H-ROM structure for multi block lengths reduces the ROM size by 42% as compared to the conventional method. Also, pipelined memory read/write scheme for inter-layer DFU operations is proposed for an optimized operation of LDPC decoder.

• Journal of Sensor Science and Technology
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• v.23 no.2
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• pp.87-93
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• 2014

In this paper, we propose a block-based low-power complementary metal oxide semiconductor (CMOS) image sensor (CIS) with a simple pixel structure for power efficiency. This method, which uses an additional computation circuit, makes it possible to reduce the power consumption of the pixel array. In addition, the computation circuit for a block-based CIS is very flexible for various types of pixel structures. The proposed CIS was designed and fabricated using a standard CMOS 0.18 ${\mu}m$ process, and the performance of the fabricated chip was evaluated. From a resultant image, the proposed block-based CIS can calculate a differing contrast in the block and control the operating voltage of the unit blocks. Finally, we confirmed that the power consumption in the proposed CIS with a simple pixel structure can be reduced.

• Geomechanics and Engineering
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• v.14 no.6
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• pp.571-580
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• 2018

The failure mechanism of tunnel roof is investigated with upper bound theorem of limit analysis. The stochastic settlement and nonlinear failure criterion are considered in the present analysis. For the collapse of tunnel roof, the surface settlement is estimated by the simplified stochastic medium theory. The failure curve expressions of collapse blocks in homogeneous and in layered soils are derived, and the effects of material parameters on the potential range of failure mechanisms are discussed. The results show that the material parameters of initial cohesion, nonlinear coefficient and unit weight have significant influences on the potential range of collapse block in homogeneous media. The proportion of collapse block increases as the initial cohesion increases, while decreases as the nonlinear coefficient and the unit weight increase. The ground surface settlement increases with the tunnel radius increasing, while the possible collapse proportion decreases with increase of the tunnel radius. In layered stratum, the study is investigated to analyze the effects of material parameters of different layered media on the proportion of possible collapse block.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.6
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• pp.488-496
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• 2019

The estimation of block erection work time at a dock is one of the important factors when establishing or managing the total shipbuilding schedule. In order to predict the work time, it is a natural approach that the existing block erection data would be used to solve the problem. Generally the work time per unit is the product of coefficient value, quantity, and product value. Previously, the work time per unit is determined statistically by unit load data. However, we estimate the work time per unit through work time coefficient value from series ships using machine learning. In machine learning, the outcome depends mainly on how the training data is organized. Therefore, in this study, we use 'Feature Engineering' to determine which one should be used as features, and to check their influence on the result. In order to get the coefficient value of each block, we try to solve this problem through the Ensemble learning methods which is actively used nowadays. Among the many techniques of Ensemble learning, the final model is constructed by Stacking Ensemble techniques, consisting of the existing Ensemble models (Decision Tree, Random Forest, Gradient Boost, Square Loss Gradient Boost, XG Boost), and the accuracy is maximized by selecting three candidates among all models. Finally, the results of this study are verified by the predicted total work time for one ship among the same series.

• Journal of information and communication convergence engineering
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• v.11 no.1
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• pp.50-55
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• 2013

In this paper, we propose a parallel intra-operation unit and a memory architecture for improving the performance of intra-prediction, which utilizes spatial correlation in an image to predict the blocks and contains 17 prediction modes in total. The design is targeted for portable devices applying H.264/AVC decoders. For boosting the performance of the proposed design, we adopt a parallel intra-operation unit that can achieve the prediction of 16 neighboring pixels at the same time. In the best case, it can achieve the computation of one luma $16{\times}16$ block within 16 cycles. For one luma $4{\times}4$ block, a mere one cycle is needed to finish the process of computation. Compared with the previous designs, the average cycle reduction rate is 78.01%, and the gate count is slightly reduced. The design is synthesized with the MagnaChip $0.18{mu}m$ library and can run at 125 MHz.

• Journal of Dental Anesthesia and Pain Medicine
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• v.22 no.3
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• pp.217-226
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• 2022

Background: Intraosseous anesthesia is the process by which an anesthetic solution, after penetration of the cortical bone, is directly injected into the spongiosa of the alveolar bone supporting the tooth. This study aimed to compare the effectiveness of the traditional inferior alveolar nerve block (IANB) and computerized intraosseous anesthesia in the surgical extraction of impacted lower third molars, compare their side effects systemically by monitoring heart rate, and assess patients' a posteriori preference of one technique over the other. Methods: Thirty-nine patients with bilaterally impacted third molars participated in this study. Each patient in the sample was both a case and control, where the conventional technique was randomly assigned to one side (group 1) and the alternative method to the contralateral side (group 2). Results: The traditional technique was faster in execution than anesthesia delivered via electronic syringe, which took 3 min to be administered. However, it was necessary to wait for an average of 6 ± 4 min from the execution to achieve the onset of IANB, while the latency of intraosseous anesthesia was zero. Vincent's sign and lingual nerve anesthesia occurred in 100% of cases in group 1. In group 2, Vincent's sign was recorded in 13% of cases and lingual anesthesia in four cases. The average duration of the perceived anesthetic effect was 192 ± 68 min in group 1 and 127 ± 75 min in group 2 (P < 0.001). The difference between the heart rate of group 1 and group 2 was statistically significant. During infiltration in group 1, heartbeat frequency increased by 5 ± 13 beats per minute, while in group 2, it increased by 22 ± 10 beats per minute (P < 0.001). No postoperative complications were reported for either technique. Patients showed a preference of 67% for the alternative technique and 20% for the traditional, and 13% of patients were indifferent. Conclusion: The results identified intraosseous anesthesia as a valid alternative to conventional anesthesia in impacted lower third molar extraction.

• The Journal of Korean Association of Computer Education
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• v.19 no.6
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• pp.55-68
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• 2016

Informatics curriculum revised 2015 proposed the use of block type and text type of programming language by organizing problem solving and the programming unit in a spiral. The purpose of this study is to find out whether the algorithms helps programming learning and whether there is a positive transition effect in block type programming learning to text type programming trailing learning. For 15 elementary school students was conducted block type and text type programming learning. As a result of the research, it is confirmed that writing the algorithm in a limited way can interfere with the learner's expression of thinking, but the block type programming learning has a positive transition to the text type programming learning. This study is meaningful that it suggested a plan for the programming education which is sequential from elementary school.

• Geomechanics and Engineering
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• v.12 no.6
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• pp.1021-1046
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• 2017

The assessment of slope stability is an essential task in geotechnical engineering. In this paper, a three-dimensional (3D) finite element analysis (FEA) was employed to investigate the performance of different shear pin arrangements to increase the stability of a soil block resting on an inclined plane with a low-interface friction plane. In the numerical models, the soil block was modeled by volume elements with linear elastic perfectly plastic material in a drained condition, while the shear pins were modeled by volume elements with linear elastic material. Interface elements were used along the bedding plane (bedding interface element) and around the shear pins (shear pin interface element) to simulate the soil-structure interaction. Bedding interface elements were used to capture the shear sliding of the soil on the low-interface friction plane while shear pin interface elements were used to model the shear bonding of the soil around the pins. A failure analysis was performed by means of the gravity loading method. The results of the 3D FEA with the numerical models were compared to those with the physical models for all cases. The effects of the number of shear pins, the shear pin locations, the different shear pin arrangements, the thickness and the width of the soil block and the associated failure mechanisms were discussed.

• Journal of Information Processing Systems
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• v.8 no.1
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• pp.159-174
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• 2012

This paper presents a study on a high-performance design for a block cipher algorithm implemented on modern many-core graphics processing units (GPUs). The recent emergence of VLSI technology makes it feasible to fabricate multiple processing cores on a single chip and enables general-purpose computation on a GPU (GPGPU). The GPU strategy offers significant performance improvements for all-purpose computation and can be used to support a broad variety of applications, including cryptography. We have proposed an efficient implementation of the encryption/decryption operations of a block cipher algorithm, SEED, on off-the-shelf NVIDIA many-core graphics processors. In a thorough experiment, we achieved high performance that is capable of supporting a high network speed of up to 9.5 Gbps on an NVIDIA GTX285 system (which has 240 processing cores). Our implementation provides up to 4.75 times higher performance in terms of encoding and decoding throughput as compared to the Intel 8-core system.

• Journal of the Korea Society of Computer and Information
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• v.19 no.9
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• pp.21-31
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• 2014

Singular value decomposition (SVD) has been widely used to identify unique features from a data set in various fields. However, a complex matrix calculation of SVD requires tremendous computation time. This paper improves the performance of a representative one-sided block Jacoby algorithm using a two-dimensional (2D) multi-core system. In addition, this paper explores an optimal multi-core system by varying the number of processing elements in the 2D multi-core system with the same 400MHz clock frequency and TSMC 28nm technology for each matrix-based one-sided block Jacoby algorithm ($128{\times}128$, $64{\times}64$, $32{\times}32$, $16{\times}16$). Moreover, this paper demonstrates the potential of the 2D multi-core system for the one-sided block Jacoby algorithm by comparing the performance of the multi-core system with a commercial high-performance graphics processing unit (GPU).