• 전자공학회논문지C
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• 제34C권9호
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• pp.22-32
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• 1997

This paper proposes an imprecise compuitation model for DCT considering QOS of images and a two dimensional DCT architecture for imprecise computations. In case that many processes are scheduling in a hard real time system, the system resources are shared among them. Thus all processes can not be allocated enough system resources (such as processing power and communication bandwidth). The imprecise computtion model can be used to provide scheduling flexibility and various QOS(quality of service)levels, to enhance fault tolerance, and to ensure service continuity in rela time systems. The DCT(discrete cosine transform) is known as one of popular image data compression techniques and adopted in JPEG and MPEG algorithms since the DCT can remove the spatial redundancy of 2-D image data efficiently. Even though many commercial data compression VLSI chips include the DCST hardware, the DCT computation is still a very time-consuming process and a lot of hardware resources are required for the DCT implementation. In this paper the DCT procedure is re-analyzed to fit to imprecise computation model. The test image is simulated on teh base of this model, and the computation time and the quality of restored image are studied. The row-column algorithm is used ot fit the proposed imprecise computation DCT which supports pipeline operatiions by pixel unit, various QOS levels and low speed stroage devices. The architecture has reduced I/O bandwidth which could make its implementation feasible in VLSI. The architecture is proved using a VHDL simulator in architecture level.

• Structural Engineering and Mechanics
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• 제50권6호
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• pp.797-816
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• 2014

Cooling tower is analyzed as an assembly of layered nonlinear shell elements. Geometric representation of the shell is enabled through layered nonlinear shell elements to define the different layers of reinforcements and concrete by considering the material nonlinearity of each layer for the cooling tower shell. Modal analysis using Ritz vector analysis and nonlinear time history analysis by direct integration method have been carried out to study the effects of the inclination of the supporting columns of the cooling tower shell on its dynamic characteristics. The cooling tower is supported by I-type columns and ${\Lambda}$-type columns supports having the different inclination angles. Relevant comparisons of the dynamic response of the structural system at the base level (at the junction of the column and shell), throat level and at the top of the tower have been made. Dynamic response of the cooling tower is found to be significantly sensitive to the change of the inclination of the supporting columns. It is also found that the stiffness of the structure system increases with increase in inclination angle of the supporting columns, resulting in decrease of the period of the structural system. The participation of the stiffness of the tower in structural response of the cooling tower is fund to be dependent of the change in the inclination angle and even in the types of the supporting columns.

• 한국농공학회지
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• 제44권4호
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• pp.107-113
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• 2002

The pipe framed and arch shape plastic greenhouse, which is the most popular greenhouse in Korea, is relatively weak in snowdrift. Reinforcement of rigid frame or column is required to reduce the damage from heavy snow in this type. But additional rigid frames or columns decrease light transmissivity or workability, and increase construction cost. So it is desirable to prepare some temporary poles and to install them when the warning of heavy snow is announced. This study was carried out to develop the temporary pole supporting system using galvanized steel pipes for plastic housing and to evaluate the safe snow load on a temporary pole. A pipe connector, which is inserted in the top of pipe used in the temporary pole and supports the center purline, was designed and manufactured to be able to carry the upper loads safely. And a bearing plate was safely designed and manufactured in order to carry the loads acting on it to the ground. When temporary poles of ${\phi}$ 25 pipe are installed at 2.4m interval, it shows that the single span plastic greenhouses with 5~7 m width are able to support the additional snow depth of 13.9~25.3 cm beyond the snow load supported by main frame.

• Computers and Concrete
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• 제19권2호
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• pp.191-201
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• 2017

External pre-stressing is often used in strengthening or retrofitting of steel-concrete composite beams. In this way, a proper numerical model should be able to trace the completely nonlinear response of these structures at service and ultimate loads. A three dimensional finite element model based on shell elements for representing the concrete slab and the steel beam are used in this work. Partial interaction at the slab-beam interface can be taken into account by using special beam-column elements as shear connectors. External pre-stressed tendons are modeled by using one-dimensional catenary elements. Contact elements are included in the analysis to represent the slipping at the tendon-deviator locations. Validation of the numerical model is established by simulating seven pre-stressed steel-concrete composite beams with experimental results. The model predictions agree well with the experimental results in terms of collapse loads, path failures and cracking lengths at negative moment regions due to service loads. Finally, the accuracy of some simplified formulas found in the specialized literature to predict cracking lengths at interior supports at service loading and for the evaluation of ultimate bending moments is also examined in this work.

• The Korean Journal of Physiology and Pharmacology
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• 제19권5호
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• pp.427-434
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• 2015

Significant evidence supports the role of the vestibular system in the regulation of blood pressure during postural movements. In the present study, the role of the vestibulo-spino-adrenal (VSA) axis in the modulation of blood pressure via the vestibulosympathetic reflex was clarified by immunohistochemical and enzyme immunoassay methods in conscious rats with sinoaortic denervation. Expression of c-Fos protein in the intermediolateral cell column of the middle thoracic spinal regions and blood epinephrine levels were investigated, following microinjection of glutamate receptor agonists or antagonists into the medial vestibular nucleus (MVN) and/or sodium nitroprusside (SNP)-induced hypotension. Both microinjection of glutamate receptor agonists (NMDA and AMPA) into the MVN or rostral ventrolateral medullary nucleus (RVLM) and SNP-induced hypotension led to increased number of c-Fos positive neurons in the intermediolateral cell column of the middle thoracic spinal regions and increased blood epinephrine levels. Pretreatment with microinjection of glutamate receptor antagonists (MK-801 and CNQX) into the MVN or RVLM prevented the increased number of c-Fos positive neurons resulting from SNP-induced hypotension, and reversed the increased blood epinephrine levels. These results indicate that the VSA axis may be a key component of the pathway used by the vestibulosympathetic reflex to maintain blood pressure during postural movements.

• 멤브레인
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• 제32권5호
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• pp.348-356
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• 2022

바이오산업의 발전으로 의약품, 식품 등의 생산 과정의 분리/정제 공정에 사용되어 왔던 기존의 컬럼 크로마토그래피를 대체하여 더 높은 처리효율을 갖는 막 크로마토그래피가 부상하고 있다. 본 연구에서는 서로 다른 기공 크기의 두 가지 상용 셀룰로오스 아세테이트(Cellulose acetate, CA) 분리막을 탈아세틸화 과정을 통해, 리간드의 개질이 용이한 다공성 재생 셀룰로오스 지지체를(Regenerated cellulose, RC) 제조하였다. 음이온 교환능을 부여하고자 grafting을 수행하였으며, 구체적으로는 UV 중합법을 통해 4차 암모늄을 포함하는 음이온 교환 리간드(MAPTAC)를 부착하여 음이온 교환용 흡착막을 제조하였다. 단백질 흡착 용량은 정적 흡착 용량(Static binding capacity, SBC)시험을 통해 총 단백질 흡착 용량을 측정했고, 동적 흡착 용량(Dynamic binding capacity, DBC)을 측정하여 상용막과 비교 평가하였다. 성능 평가 결과 단백질 흡착량은 넓은 표면적에 의해 리간드 밀도가 높은, 기공 크기가 작은 순서로 높게 측정되었고, 상용 CA분리막을 탈아세틸화하고 리간드를 부착시킨 분리막(RC 0.8 + MAPTAC 43.69 mg/ml, RC 3.0 + MAPTAC 36.33 mg/ml)이 상용 막 크로마토그래피 제품(28.38 mg/ml) 대비 높은 흡착 용량을 보였다.

• 대한환경공학회지
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• 제29권5호
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• pp.571-576
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• 2007

본 연구에서는 세 가지 다른 방법으로 제조된 망간사에 의한 용존 $Mn^{2+}$의 제거특성을 회분식 및 칼럼실험을 통하여 조사하였다. 실험실 규모에서 망간의 주입농도를 달리하여 망간사 제조시, 모래에 코팅된 망간 코팅량은 주입된 망간 농도에 비례하여 나타났다. 망간사에 의한 용존 망간의 제거는 용액의 pH 증가에 따라 증가하는 양이온형 흡착경향을 따랐다. 흡착을 통한 용존 망간의 제거는 망간사 코팅방법 및 코팅량에 거의 영향을 받지 않고 모든 pH 영역에서 유사하게 나타났다. NaClO를 산화제로써 주입하였을 때 망간사에 의한 용존 망간의 제거는 NaClO 농도에 비례하였다. 이러한 결과는 NaClO 주입농도 증가에 따라 용존 망간이 망간산화물로 산화되고 이때 생성되는 산화망간이 망간사 표면으로의 코팅이 증가되어 나타난 현상으로 여겨진다. 칼럼반응기를 이용한 용존 망간제거 실험에서, NaClO를 주입하지 않은 경우에는 4,100 bed volume 이 후 땅간의 파과가 이루어졌지만, NaClO를 주입하였을 경우에는 파과가 1.6배 지연되어 나타나서 산화제를 사용하는 것이 용존 망간의 제거율을 높이는 것임을 또한 확인할 수 있었다.

• Earthquakes and Structures
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• 제11권3호
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• pp.483-503
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• 2016

This study aims to evaluate seismic performance of existing low and mid-rise reinforced concrete buildings by comparing their displacement capacities and displacement demands under selected ground motions experienced in Turkey as well as demand spectrum provided in 2007 Turkish Earthquake Code for design earthquake with 10% probability of exceedance in 50 years for soil class Z3. It should be noted that typical residential buildings are designed according to demand spectrum of 10% probability of exceedance in 50 years. Three RC building sets as 2-, 4- and 7-story, are selected to represent reference low-and mid-rise buildings located in the high seismicity region of Turkey. The selected buildings are typical beam-column RC frame buildings with no shear walls. The outcomes of detailed field and archive investigation including approximately 500 real residential RC buildings established building models to reflect existing building stock. Total of 72 3-D building models are constructed from the reference buildings to include the effects of some properties such as structural irregularities, concrete strength, seismic codes, structural deficiencies, transverse reinforcement detailing, and number of story on seismic performance of low and mid-rise RC buildings. Capacity curves of building sets are obtained by nonlinear static analyses conducted in two principal directions, resulting in 144 models. The inelastic dynamic characteristics are represented by "equivalent" Single-Degree-of- Freedom (ESDOF) systems using obtained capacity curves of buildings. Nonlinear time history analysis is used to estimate displacement demands of representative building models idealized with (ESDOF) systems subjected to the selected ground motion records from past earthquakes in Turkey. The results show that the significant number of pre-modern code 4- and 7-story buildings exceeds LS performance level while the modern code 4- and 7-story buildings have better performances. The findings obviously indicate the existence of destructive earthquakes especially for 4- and 7-story buildings. Significant improvements in the performance of the buildings per modern code are also obvious in the study. Almost one third of pre-modern code buildings is exceeding LS level during records in the past earthquakes. This observation also supports the building damages experienced in the past earthquake events in Turkey.

• Steel and Composite Structures
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• 제10권6호
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• pp.541-561
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• 2010

This paper presents finite element analyses, experimental measurements and finite element model updating of an arch type steel laboratory bridge model using semi-rigid connections. The laboratory bridge model is a single span and fixed base structure with a length of 6.1 m and width of 1.1m. The height of the bridge column is 0.85 m and the maximum arch height is 0.95 m. Firstly, a finite element model of the bridge is created in SAP2000 program and analytical dynamic characteristics such as natural frequencies and mode shapes are determined. Then, experimental measurements using ambient vibration tests are performed and dynamic characteristics (natural frequencies, mode shapes and damping ratios) are obtained. Ambient vibration tests are performed under natural excitations such as wind and small impact effects. The Enhanced Frequency Domain Decomposition method in the frequency domain and the Stochastic Subspace Identification method in the time domain are used to extract the dynamic characteristics. Then the finite element model of the bridge is updated using linear elastic rotational springs in the supports and structural element connections to minimize the differences between analytically and experimentally estimated dynamic characteristics. At the end of the study, maximum differences in the natural frequencies are reduced on average from 47% to 2.6%. It is seen that there is a good agreement between analytical and experimental results after finite element model updating. Also, connection percentages of the all structural elements to joints are determined depending on the rotational spring stiffness.

• 한국어류학회지
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• 제10권2호
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• pp.231-240
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• 1998

납자루아과(亞科)에 속하는 가시납지리(Acanthorhodeus gracilis)의 두골(頭骨), 척주(脊柱), 지느러미 골격을 조사하였다. 두개부(頭蓋部)에 천문이 없으며, 상사골(上篩骨)의 전단에 돌기가 없고, 안와설골(眼窩楔骨)은 2개로 되어 있다. 기저후두골(基底後頭骨) 돌기(突起)는 전반부에서부터 발달하였고, 상후두골(上後頭骨)은 높은 삼각형 형태의 돌기를 갖고 있으며, 미설골(尾舌骨)은 선단(先端)이 2분기(分技)되고 수평판(水平板)과 수직판(垂直板)의 후방(後方)이 넓어지며 후연(後緣)이 돌출되어 있다. 인두치(咽頭齒)는 1열로 인두치식(咽頭齒式)은 5 - 5이며 4개의 유리치(遊離齒)를 갖고 있다. 편대(扁帶)에는 오훼골(烏喙骨) 구멍이 없으며, 미골추체(尾骨推體)에는 미신경골(尾神經骨)이 나타나지 않고, 길고 가느다란 후요대돌기(後腰帶突起)를 갖는다. 유리신경간련(遊離神經間練)은 넓은 판상(板狀)이고, 신경간극(神經間棘)은 14~15개이며 제1~제4신경간극(神經間棘)은 하나의 기기골을 나머지는 두 개의 기기골을 기부(基部)에 갖고 있고, 혈관간극(血管間棘)은 11~12개이며 제1~제 4혈관간극(血管間棘)은 하나의 기기골을 나머지는 두 개의 기기골을 갖고있다.