• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5C
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• pp.454-463
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• 2010

After the efficiency of H.264 video compression has been announced, it replaced MPEG-2 standard in several applications. So transcoding methods of MPEG-2 to H.264 have been studying because there are variety devices and contents followed by MPEG-2. Although H.264 supported various service such as IPTV, DMB, digital broadcasting etc, but users using MPEG-2 devices cannot accessible to them. This paper propose H.264 to MPEG-2 transcoding for users of MPEG-2 devices without displacement H.264. The proposed method predicted a motion vector for MPEG-2 encoder after it extracted from motion vectors of variable blocks in H.264 to improve processing time. Also it predicted a optimal motion vector using modified boundary matching algorithm after grasped a special character for boundary and background of object. The experimental results from proposed method show a considerable reduction in processing time, as much as 68% averagely, with a small objective quality reduction in PSNR.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.11
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• pp.3694-3722
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• 2022

In today's globalized world, there is no transparency in exchanging data and information between producers and consumers. However, these tasks experience many challenges, such as administrative barriers, confidential data leakage, and extensive time delays. To overcome these challenges, we propose a decentralized, secured, and verified smart chain framework using Ethereum Smart Contract which employs Inter Planetary File Systems (IPFS) and MongoDB as storage systems to automate the process and exchange information into blocks using the Tendermint algorithm. The proposed work promotes complete traceability of the product, ensures data integrity and transparency in addition to providing security to their personal information using the Lelantos mode of shipping. The Tendermint algorithm helps to speed up the process of validating and authenticating the transaction quickly. More so in this time of pandemic, it is easier to meet the needs of customers through the Ethermint Smart Chain, which increases customer satisfaction, thus boosting their confidence. Moreover, Smart contracts help to exploit more international transaction services and provide an instant block time finality of around 5 sec using Ethermint. The paper concludes with a description of product storage and distribution adopting the Ethermint technique. The proposed system was executed based on the Ethereum-Tendermint Smart chain. Experiments were conducted on variable block sizes and the number of transactions. The experimental results indicate that the proposed system seems to perform better than existing blockchain-based systems. Two configuration files were used, the first one was to describe the storage part, including its topology. The second one was a modified file to include the test rounds that Caliper should execute, including the running time and the workload content. Our findings indicate this is a promising technology for food supply chain storage and distribution.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.1
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• pp.80-87
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• 2006

SONY corporation preoccupies $80\%$ of a market of the CCD used in a CCTV system. The CCD of SONY have high duality which can not follow the progress of capability. But there are some problems which differ the clock frequency used in CCD from the frequency used in common video encoder. To get the result by using common video encoder, the system needs a scaler that could adjust image size and PLL that synchronizes CCD's with encoder's clock So, this paper proposes the video encoder that is activated at equal clock used in CCD without scaler and PLL. The encoder converts ITU-R BT.601 4:2:2 or ITU-R BT.656 inputs from various video sources into NTSC or PAL signals in CVBS. Due to variable clock, property of filters used in the encoder is automatically changed by clock and filters adopt multiplier-free structures to reduce hardware complexity. The hardware bit width of programmable digital filters for luminance and chrominance signals, along with other operating blocks, are carefully determined to produce hish-quality digital video signals of ${\pm}1$ LSB error or less. The proposed encoder is experimentally demonstrated by using the Altera Stratix EP1S80B953C6ES device.

• Sleep Medicine and Psychophysiology
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• v.15 no.1
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• pp.39-43
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• 2008

Objectives: The pathophysiology of restless legs syndrome (RLS) is not obvious, but many promising theories involve dopaminergic deficiency and genetic causes. The RLS is presumed to occur more frequently among schizophrenic patients who take antipsychotics, most of which blocks the dopamine receptors. This study aimed to investigate whether dopamine transporter gene (DAT1) 40 base pair (bp) variable number of tandem repeat (VNTR) polymorphism is associated with the antipsychotic-induced RLS in schizophrenia. Methods: We determined the diagnosis of RLS among the 190 Korean schizophrenic patients by the diagnostic criteria of the International Restless Legs Syndrome Study Group (IRLSSG). Genotyping was performed for the 40bp VNTR in DAT1 gene using polymerase chain reaction. Results: We separated the schizophrenic patients into 44 patients with RLS and 146 patients without RLS. The genotype and allele frequencies did not differ significantly between two groups. Conclusions: These results suggest that DAT1 gene 40bp VNTR is not associated with the antipsychotic-induced RLS in schizophrenia. To confirm these results, larger-scale association study is needed in the future.

• Journal of Dental Anesthesia and Pain Medicine
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• v.22 no.2
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• pp.145-153
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• 2022

Background: Postoperative analgesia (POA) is an important determinant of successful treatment. Dexmedetomidine (DEX) has recently gained attention as a promising adjuvant to local anesthetics (LA). The present study aimed to evaluate the efficacy and safety of levobupivacaine (LB) as an adjuvant during inferior alveolar nerve block (IANB) in the extraction of lower impacted third molars (LITM). Methods: A prospective, randomized, placebo-controlled, triple-blind, parallel-arm, and clinical study was performed on 50 systemically healthy participants who required removal of an asymptomatic LITM. Using a 1:1 distribution, the participants were randomized into two groups (n = 25). Group L (control group) received 1.8 mL of 0.5% LB and 0.2 mL normal saline (placebo) and Group D (study group) received a blend of 1.8 mL of 0.5% LB and 0.2 mL (20 ㎍) DEX. The primary outcome variable was the duration of POA and hemodynamic stability, and the secondary variable was the total number of analgesics required postoperatively for up to 72 h. The participants were requested to record the time of rescue analgesic use and the total number of rescue analgesics taken. The area under the curve was plotted for the total number of analgesics administered. The pain was evaluated using the visual analog scale. Data analysis was performed using paired students and unpaired t-test, Mann-Whitney U test, Chi-square test, and receiver operating characteristic analysis. Statistical significance was set at P < 0.05. Results: The latency, profoundness of anesthesia, and duration of POA were statistically significant (P < 0.05). The differences between mean pain scores at 6, 12, 24, 48, and 72 h were found to be significant (each P = 0.0001). Fewer analgesics were required by participants in group D (2.12 ± 0.33) than in L (4.04 ± 0.67), with a significant difference (P = 0.0001). Conclusion: Perineurally administered LA with DEX is a safe, effective, and therapeutic approach for improving latency, providing profound POA, and reducing the need for postoperative analgesia.

• The Korean Journal of Petroleum Geology
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• v.5 no.1_2 s.6
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• pp.36-47
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• 1997

This study presents multi-variable sequence model for a broader application of sequence concept proposed by Exxon group. The concept of the multi-variable model is based on the fact that internal organization and boundary type of the sequences are determined by three varying factors including 3rd-order cycles of eustasy, and tectonic movement and sediment influx with 2nd-order changes. Instead of Exxon group's systems tracts, this model adopts parasequence sets as the fundamental building blocks of the sequence, because they are descriptive stratigraphic units simply defined by internal stacking pattern, reflecting interactions of accommodation and sediment influx. Seven sequence types which vary in number and type of internal parasequence sets are formulated as associations of four types of accommodation development and three grades of sediment influx. In the southwestern margin of Ulleung Basin, the multi-variable sequence analysis of shelf-slope sequence shows systematic changes in stratal patterns and the numbs, of constituent parasequence sets (i.e. sequence type). These changes are interpreted to reflect temporal and spatial changes in type and rate of tectonic movement and sediment influx, as a result of back-arc opening and closing. During the back-arc opening, rapid subsidence, continuous rise of relative sea level, and high sediment influx gave rise to sequences dominantly of single progradational parasequence set. In the early stage of back-arc closing accompanied by local contractional deformation, different types of sequences contemporaneously formed depending on the spatial changes in tectonically-controlled accommodation and influx rates. During the subsequent slow back-arc subsidence, rise-dominated relative sea-level cycle was coupled with moderate to high sedimentation rate to have resulted in sequences consisting of $2~3$ parasequence sets.

• Restorative Dentistry and Endodontics
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• v.31 no.6
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• pp.477-484
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• 2006

The purposes of this study were to compare the apical terminus width of simulated curved root canal prepared with three NiTi file systems used by undergraduates for evaluation the effects of flute angle and pitch or radial land on reducing screw-in effect and to determine more safe NiTi file system for inexperienced operators. Fifty inexperienced undergraduate students prepared 150 simulated curved root canals in resin blocks with three NiTi file systems ; ProFile$^{(R)}$, Hero Shaper$^{(R)}$, K3$^{TM}$. The electric motor set at a speed of 300 rpm and torque of 30 in a 16 : 1 reduction handpiece was used. The simulated root canal was prepared to ISO #25 sizes with each file system. The scanned images of pre- and post-instrumented canal of resin block were superimposed. To evaluate the screw-in effect of three NiTi file systems, apical terminus width of root canal was measured from superimposed images and statistical analysis was performed. There were significant differences in three NiTi flle systems. ProFile$^{(R)}$ had significantly smaller width than Hero Shaper$^{(R)}$ and K3$^{TM}$"" (P < 0.05), but no significant difference was observed between K3$^{TM}$ and Hero Shaper$^{(R)}$. Under the condition of this study, active file system (Hero SHaper$^{(R)}$, K3$^{TM}$) with variable pitch and helical angle had more screw-in effect than passive file system (ProFile$^{(R)}$) with constant pitch and helical angle. It seems that the radial lands play more important role in reducing screw-in effect.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.4
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• pp.292-298
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• 2012

Purpose: The purpose of this study is to ascertain the stability of the implant by comparing the effects of the change of implant diameter, length and design on implant stability quotient. Materials and methods: To remove the variable due to the difference of bone quality, the uniform density (0.48 g/$cm^3$) Polyuretane foam blocks (Sawbones$^{(R)}$, Pacific Research Laboratories Inc, Vashon, Washington) were used. Implants (Implantium$^{(R)}$, Dentium, Seoul, Korea) were placed with varying diameters (${\phi}3.8$, ${\phi}4.3$ and ${\phi}4.8$) and length (8 mm, 10 mm and 12 mm), to assess the effect on implant stability index (ISQ). Also the influence of the design of the submerged and the non-submerged (SimplelineII$^{(R)}$, Dentium, Seoul, Korea) on ISQ was evaluated. To exclude the influence of insertion torque, a total of 60 implants (n = 10) were placed with same torque to 35 N. Using Osstell$^{TM}$ mentor (Integration Diagnostic AB, Sweden) ISQ values were recorded after measuring the resonant frequency, one-way ANOVA and Tukey HSD test results were analyzed. (${\alpha}$=0.05). Results: 1. The change of the diameter of the implant did not affect the ISQ (P>.05), but the increase of implant length increased the ISQ(P<.001). 2. The change in implant design were correlated with the ISQ, and the ISQ of submerged design was significantly higher than that of the non-submerged design(P<.05). Conclusion: In order to increase implant stability, the longer implant is better to be selected, and on the same length of implant, submerged design is thought to be able to get a higher ISQ than the non-submerged.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.12
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• pp.1870-1883
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• 1993

In this paper, in order to build up the User Network Interface based on ATM, a study on traffic control techniques which should be performed by main function groups-B 75,5 NT2, LEX-is discussed. The structure of B-NT2 which is the most important function group In the User Network Interface is defined in quite a simple manner in addition, the functional blocks of LEX are defined in a similar manner as those of B NT2. It is possible to distribute total traffic control functions by using the similarities between B-NT2 and LEX and by allocating virtual path identifiers fixedly according to the characteristics of the traffics. For the traffic control techniques of ATM, relations among Connection Admtsslon Control, Usage Parameter Control and Bandwidth Allocation Control are defined and Multi Rule Base structure to realize optimal control functions according to the characteristics of the source traffics is proposed. And the Real-time Variable Window algorithmsimply designed to be suitable for the Multi Rule Base architecture is also proposed. The performances of the proposed algorithm are analyzed through the computer simulation by generating on-off source traffic in a virtual system that has the form of the proposed hardware. The analyzed results show that the distributed control is possible and that the implementation of the proposed architecture and algorithm is possible.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.3
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• pp.301-311
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• 2015

Objectives: Operators of overhead traveling crane in a ship assembly factory perform work to transmit large vessel blocks to an appropriate working process. Hazardous matters such as metal dusts, carbon monoxide, carbon dioxide, ozone, loud noise and fine particles are generated by variable working activities in the factory. The operators could be exposed to the hazardous matters during the work. In particular, welding fumes comprised of ultra fine particles and heavy metals is extremely hazardous for humans when exposing a pulmonary through respiratory pathway. Occupational lung diseases related to welding fumes are increasingly on an upward tendency. Therefore, the objective of this study is to assess properly unknown occupational exposure to the welding fumes among the operators. Methods: This study intended to clearly determine an equivalence check whether or not chemical constituents and composition of the dusts, which existed in the driver's cab, matched up with generally known welding fumes. Furthermore, computational fluid dynamics program(CFD) was used to identify a ventilation assessment in respect of a contamination distribution of welding fumes in the air. The operators were investigated to assess personal exposure levels of welding fumes and respirable particulate. Results: The dust in an operation room were the same constituents and composition as welding fumes. Welding fumes, which caused by the welding in a floor of the factory, arose with an ascending air current up to a roof and then stayed for a long time. They were considered to be exposed to the welding fumes in the operation room. The personal exposure levels of welding fumes and respirable particulate were 0.159(n=8, range=0.073-0.410) $mg/m^3$ and 0.138(n=8, range=0.087-0.178) $mg/m^3$, respectively. They were lower than a threshold limit value level($5mg/m^3$) of welding fumes. Conclusions: These findings indicate that an occupational exposure to welding fumes can exist among the operators. Consequently, we need to be keeping the operators under a constant assessment in the operator process of overhead traveling crane.