• 한국방송∙미디어공학회:학술대회논문집
• /
• 한국방송공학회 2012년도 추계학술대회
• /
• pp.71-74
• /
• 2012

본 논문에서는 현재의 HDTV와 3DTV보다 4배 이상 초고화질의 UHDTV와 Full-HD급 3DTV 등 지상파에서의 차세대방송 구현 가능성을 DVB-T2 전송방식과 HEVC 압축방식을 기반으로 설명한다. 4K 혹은 8K-UHDTV 대용량 데이터전송을 위하여 일본과 여러 나라에서 새로운 전송기술을 연구 중이지만 여기서는 현재 상용화된 기술 중 DVB-T2 전송기술을 중심으로 자료를 통하여 가능성을 알아본다. 지상파방송 디지털전환에 이어 또다시 차세대방송을 위한 전환의 성공조건으로 UHDTV와 3DTV전송도 중요하지만 시청자 직접수신과 실내수신 및 언제 어디서나 자유로운 수신환경 제공도 매우 중요하다. 그러므로 본 논문에서는 효율적인 주파수 활용과 수신능률 향상을 위하여 VHF대역과 UHF 700MJHz대역 등 2개의 서로 다른 주파수 대역을 이용한 SFN 송출망의 효과를 제시하고, 소출력 Gap Filler 및 가정용 SFN Gap Filler를 활용한 자유로운 수신환경 구성을 제안하고 있다.

• 한국해양학회지
• /
• 제8권2호
• /
• pp.68-74
• /
• 1973

The present paper concerns the age determination and growth of butter fish, Pampus argenteus from the southwestern waters of Korea by otolith reading. 743 specimens taken by stow-net in the southern part of the Yellow Sea and northeastern part of the East China Sea during the period from October 1972 to September 1973 were examined. Results of the study are summarized as follows: 1. Sex ratio of females to males was found to be 2:1. 2. Ring marks on the otolith were found to be formed twice a year, once during the period of January-May and the other time in September. 3. The Lee's phenomenon was observed on the otolith sample. 4. The relationship between the radius of otolith(R) and fork length(L) was found to be as follows: R=0.3069+0.0133L 5. Calculated fork length at the time of otolith ring formation are found to be as follows:I-ring,71.67mm; II-ring, 125.05mm; III-ring, 168.65mm; IV-ring, 201.74mm; V-ring, 225.80mm; VI-ring, 240.84mm. 6. Maximum fork length calculated according to the diagram of Walford's growth transformation was found to be 281.5mm. 7. Growth curve, when related to the von Bertalanffy's equation, was laid out as $L_{t}=281.5[1-e$^{-0.674(t-0.128)}]$

• 대한족부족관절학회지
• /
• 제23권2호
• /
• pp.74-77
• /
• 2019

Fibroma of the tendon sheath (FTS) was initially described in 1936 by Geschickter and Copeland as a benign firmed soft tissue tumor that is rare and less common than another soft tissue tumors, especially giant cell tumors (GCT) of the tendon sheath. The common distinct feature is a slow-growing least painful rare entity arising from the tendon or tendon sheath. FTS is detected mostly in the fingers, hands and wrists but less commonly in the foot. Very few cases of FTS have been described arising from a flexor tendon of the foot. This article describes a 51-year-old patient with FTS that developed in the extensor tendon of the foot, which is the only known FTS to form in this area. Heterogeneous low signal intensity in both the T1- and T2-weighted images was observed in magnetic resonance imaging. The lesion was excised completely by open surgery. Histologically, it showed randomly arranged, fibroblast-like spindle cells in dense fibrous tissue and had insufficient hemosiderin-laden macrophages that are typical for GCT.

• 소성∙가공
• /
• 제32권2호
• /
• pp.74-80
• /
• 2023

A deformation behavior of commercially pure titanium (CP-Ti) is highly dependent on material and processing parameters, such as deformation temperature, deformation direction, and strain rate. This study aims to predict the multivariable and nonlinear tensile behavior of CP-Ti using machine learning based on three algorithms: artificial neural network (ANN), light gradient boosting machine (LGBM), and long short-term memory (LSTM). The predictivity for tensile behaviors at the cryogenic temperature was lower than those in the room temperature due to the larger data scattering in the train dataset used in the machine learning. Although LGBM showed the lowest value of root mean squared error, it was not the best strategy owing to the overfitting and step-function morphology different from the actual data. LSTM performed the best as it effectively learned the continuous characteristics of a flow curve as well as it spent the reduced time for machine learning, even without sufficient database and hyperparameter tuning.

• 상하수도학회지
• /
• 제13권4호
• /
• pp.54-61
• /
• 1999

SBR process used to evaluate the removal of organics, nitrogen and phosphorus on the basis of a report of research on a precedence at various operation cycle and condition change. Effluent concentration of COD were 50mg/l, 50mg/l, 90mg/l respectively, The removal rates of COD were nearly over 95% at Run 1, 2 and 4. But at Run 3, Effluent concentration of COD was 255.0mg/l, The removal rate of COD was 87% at Run 3. As Oxic/Anoxic rate was fixed and operating cycle of Oxic/Anoxic was changed, the removal rates of T-N were 74.7%, 46.9%, 28.5%, 63.3% respectively at Run 1~4. The case of Run 1 was best result. The removal rates of T-P was appeared in proportion to T-N removal rates and rest of $NO_2-N$. The removal rates of T-P were 51.2%, 35.5%, 41.5%, 51.9% respectively. The removal rates of COD, T-N, T-P were influenced on the change of SBR operation cycle. As organic loading rate was $1.43kgCOD/m^3day$ and C/N ratio was 3.0, operation cycle of Run 1 was best condition of T-N removal rates and T-P removal.

• 환경영향평가
• /
• 제21권5호
• /
• pp.745-755
• /
• 2012

The relations between tributaries and mainstream were identified with the water qualities measurements in the field. Parameters of water qualities were BOD, T-N, T-P and measurements were performed by 4 events of rainfalls for 2011. The precipitation data influenced on pollutants loads. Pollutants loads were fluctuations with the seasonal variation. Gajoacheon contributed in 18.39% of BOD, 23.79% of T-N, 15.23% of T-P and Nabulcheon contributed in 13.54% of BOD, 13.05% of T-N and 13.66% of T-P in the region from Nam River_C to Nam River_D. In case of the region from Nam River_C to Nam River_D, Yongacheon river inflowed to main stream as 23.65% of BOD, 20.74% of T-N, and 15.05% of T-P.

• Progress in Superconductivity
• /
• 제10권2호
• /
• pp.74-78
• /
• 2009

Inter-grain nanobridges of the $MgB_2$ superconductor have been fabricated by focused-ion-beam(FIB) and their electrical transport properties were studied. The $MgB_2$ film was prepatterned into microbridges by a standard argon ion milling technique and then FIB-patterned into 100 nm$\times$100 nm bridges. Current-voltage characteristics showed a strong flux-flow type behavior at all temperatures with a trait of Josephson coupling near $T_c$. At low temperatures, the curves showed a two-step resistance-doubled transition with occasional hysteresis. The resistance-doubling transition is believed to be due to a two-channel flux-flow effect. The temperature-dependent critical current data showed $I_c(T){\propto}(1-T/T_c)^2$ near $T_c$, same as a normal barrier junction, and $I_c(T){\propto}(1-T/T_c)^{1.2}$ at low temperatures, similar to that of a film.

• Wind and Structures
• /
• 제38권5호
• /
• pp.367-379
• /
• 2024

Compared with traditional transmission towers, T-shaped angle towers have long cross-arms and are specially used for ultrahigh-voltage direct-current (UHVDC) transmission. Nevertheless, the wind loads of T-shaped towers have not received much attention in previous studies. Consequently, a series of wind tunnel tests on the T-shaped towers featuring cross-arms of varying lengths were conducted using the high-frequency force balance (HFFB) technique. The test results reveal that the T-shaped tower's drag coefficients nearly remain constant at different testing velocities, demonstrating that Reynolds number effects are negligible in the test range of 1.26 × 10⁴-2.30 × 10⁴. The maximum values of the longitudinal base shear and torsion of the T-shaped tower are reached at 15° and 25° of wind incidence, respectively. In the yaw angle, the crosswind coefficients of the tower body are quite small, whereas those of the cross-arms are significant, and as a result, the assumption in some load codes (such as ASCE 74-2020, IEC 60826-2017 and EN 50341-1:2012) that the resultant force direction is the same as the wind direction may be inappropriate for the cross-arm situation. The fitting formulas for the wind load-distribution factors of the tower body and cross-arms are developed, respectively, which would greatly facilitate the determination of the wind loads on T-shaped angle towers.

• The Plant Pathology Journal
• /
• 제27권2호
• /
• pp.170-182
• /
• 2011

Plants possess multiple resistance mechanisms that protect themselves against pathogen attack. To identify unknown components of the defense machinery in Arabidopsis, gene-expression changes were monitored in Arabidopsis thaliana under 18 different biotic or abiotic conditions using a DNA microarray representing approximately 25% of all Arabidopsis thaliana genes (www.genevestigator.com). Seventeen genes which are early responsive to salicylic acid (SA) treatment as well as pathogen infection were selected and their T-DNA insertion mutants were obtained from SALK institute. To elucidate the role of each gene in defense response, bacterial pathogen Pseudomonas syringae pv. tomato (Pst) DC3000 was inoculated onto individual T-DNA insertion mutants. Four mutants exhibited decreased resistance and five mutants displayed significantly enhanced resistance against Pst DC3000-infection as measured by change in symptom development as compared to wild-type plants. Among them, member of uridin diphosphate (UDP)-glycosyltransferase (UGT) was of particular interest, since a UGT mutant (At1g05680) showed enhanced resistance to Pst-infection in Arabidopsis. In systemic acquired resistance (SAR) assay, this mutant showed enhanced activation of SAR. Also, the enhanced SAR correlated with increased expression of defense-related gene, AtPR1. These results emphasize that the glycosylation of UGT74E2 is a part of the SA-mediated disease-resistance mechanism.

• 한국운동역학회지
• /
• 제25권3호
• /
• pp.335-342
• /
• 2015

Objective : The purposes of this study was to analyze the effects of the stirrup length fitted to the rider's lower limb length and it's impact on less skilled riders during trot in equestrian events. Methods : Participants selected as subjects consisted of less skilled riders(n=5, mean age: $40.02{\pm}10.75yrs$, mean heights: $169.77{\pm}2.08cm$, mean body weights: $67.65{\pm}7.76kg$, lower limb lengths: $97.26{\pm}2.35cm$, mean horse heights: $164.00{\pm}5.74cm$ with 2 type of stirrups lengths(lower limb ratio 74.04%, and 79.18%) during trot. The variables analyzed consisted of the displacement for Y axis and Z axis(head, and center of mass[COM]) with asymmetric index, trunk front-rear angle(consistency index), lower limb joint(Right hip, knee, and ankle), and average vertical forces of horse rider during 1 stride in trot. The 4 camcorder(HDR-HC7/HDV 1080i, Spony Corp, Japan) was used to capture horse riding motion at a rate of 60 frames/sec. Raw data was collected from Kwon3D XP motion analysis package ver 4.0 program(Visol, Korea) during trot. Results : The movements and asymmetric index didn't show significant difference at head and COM, Also, 74.04% stirrups lengths in trunk tilting angle showed significant difference with higher consistency than that of 79.18% stirrups lengths. Hip and knee joint angle showed significant difference with more extended posture than that of 74.04% stirrups lengths during trot. Ankle angle of 79.18% stirrups length showed more plantarflexion than that of 74.04% stirrups lengths. Average vertical force of rider showed significant difference with higher force at 79.18% stirrups lengths than that of 74.04% stirrups lengths during stance phase. Conclusion : When considering the above, 74.04% stirrups length could be effective in impulse reduction with consistent posture in rather less skilled horse riders.