• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2006년도 제5회 박판성형 SYMPOSIUM
• /
• pp.40-44
• /
• 2006

Sandwich structures, which are composed of a thick core between two faces, are commonly used in many engineering applications because they combine high stiffness and strength with low weight. Accordingly, the usage of sandwich structure is very widely applied to the aircraft, the automobile and marine industry, etc., because of these advantages. In this paper, we have investigated the buckling protection of an inner structure plate and the useful corrugated configuration for contact, and the fabrication method of the inner structure plate for large area using the continuous molding process. Also, we have guaranteed the accuracy of the molding process through the micro corrugated mold fabrication and secured the accuracy and analyzed aspect properties of the inner structure plate fabricated for a large area using the partial mold process.

• International Journal of Aeronautical and Space Sciences
• /
• 제13권2호
• /
• pp.260-265
• /
• 2012

Satellite devices for fine attitude control of the Science & Technology Satellite-2 (STSAT-2). Based on the mission requirements of STSAT-2, the conventional analog-type sun sensors were found to be inadequate, motivating the development of a compact, fast and fine digital sun sensor (FDSS). The FDSS uses a CMOS image sensor and has an accuracy of less than 0.03degrees, an update rate of 5Hz and a weight of less than 800g. A pinhole-type aperture is substituted for the optical lens to minimize its weight. The target process speed is obtained by utilizing the Field Programmable Gate Array (FPGA), which acquires images from the CMOS sensor, and stores and processes the image data. The sensor accuracy is maintained by a rigorous centroid algorithm. This paper describes the FDSS designs, realizations, tests and calibration results.

• Structural Engineering and Mechanics
• /
• 제17권5호
• /
• pp.671-690
• /
• 2004

A meshless method with novel variation of point collocation by finite mixture approximation is developed in this paper, termed the meshless finite mixture (MFM) method. It is based on the finite mixture theorem and consists of two or more existing meshless techniques for exploitation of their respective merits for the numerical solution of partial differential boundary value (PDBV) problems. In this representation, the classical reproducing kernel particle and differential quadrature techniques are mixed in a point collocation framework. The least-square method is used to optimize the value of the weight coefficient to construct the final finite mixture approximation with higher accuracy and numerical stability. In order to validate the developed MFM method, several one- and two-dimensional PDBV problems are studied with different mixed boundary conditions. From the numerical results, it is observed that the optimized MFM weight coefficient can improve significantly the numerical stability and accuracy of the newly developed MFM method for the various PDBV problems.

• 한국농림기상학회지
• /
• 제4권4호
• /
• pp.197-202
• /
• 2002

A new method is used to estimate the amount of water evaporation from Class A Pan with higher precision and accuracy. The principle of method is to detect the weight change of a buoyant sinker resulting from a change in water level of Class A Pan. A strain-gauge load cell is used to measure the weight change. Field observation of evaporation was done at Pohang Meteorological Station from June 24 to August 4, 2002. By using this new method, it is possible to measure hourly evaporation accurately even under a strong solar radiation and wind disturbance, enabling a direct comparison of evaporation with other meteorological elements. At night, under low humidity and high wind speed conditions, more evaporation was recorded than during daytime. Maximum evaporation rates observed during this period exceed 1.0 mm/hour under the sunny and windy conditions with low humidity. To understand relationships between meteorological elements and latent heat flux at ground level, we suggest intensive held experiments using high accuracy evaporation recording instruments with hourly time interval.

• 한국음향학회:학술대회논문집
• /
• 한국음향학회 1993년도 학술논문발표회 논문집 제12권 1호
• /
• pp.117-120
• /
• 1993

In this paper, we explore the possibility of URAN(Universally Reconstructable Artificial Neural-network) VLSI chip for speech recognition. URAN, a newly developed analog-digital hybrid neural chip, is discussed in respects to its input, output, and weight accuracy and their relations to its performance on speaker independent digit recognition. Multi-layer perceptron(MLP) nets including a large frame input layer are used to recognize a digit syllable at a forward retrieval. The simulation results using the full and limited floating precision computations for the input, output, and weight variables of the network give the comparable classification performance. An MLP with piecewise linear hidden and output units is also trained successfully using low accuracy computation.

• Computers and Concrete
• /
• 제29권 6호
• /
• pp.361-374
• /
• 2022

On the premise of ensuring that the automatic and quantitative discharging function of concrete conveyors is met, the accuracy of the weight forecast by the mathematical model of the screw conveying volume is improved, and the error of the weight of the concrete parts and the accumulation thickness is reduced. In this paper, the discrete element method (DEM) is used to simulate the macroscopic flow of concrete. Using the concrete discrete element model, the size of the screw conveyor is set, and establish the response model between the influencing factors (process and structure) and the concrete mass flow rate according to the design points of the screw discharging experiment. The nonlinear data fitting method is used to obtain the volumetric efficiency function under the influence of process and structural factors, and the traditional screw conveying volume model is improved. The mass flow rate of concrete predicted by the improved mathematical model of screw conveying volume is consistent with the test results. The model can accurately describe the conveying process of concrete and achieve the purpose of improving the accuracy of forecasting the weight of discharged concrete.

• 한국멀티미디어학회논문지
• /
• 제25권1호
• /
• pp.39-51
• /
• 2022

Image-based gender classification and age estimation of human are classic problems in computer vision. Most of researches in this field focus just only one task of either gender classification or age estimation and most of the reported methods for each task focus on accuracy performance and are not computationally light. Thus, running both tasks together simultaneously on low cost mobile or embedded systems with limited cpu processing speed and memory capacity are practically prohibited. In this paper, we propose a novel light-weight gender classification and age estimation method based on ensemble multitasking deep learning with light-weight processing neural network architecture, which processes both gender classification and age estimation simultaneously and in real-time even for embedded systems. Through experiments over various well-known datasets, it is shown that the proposed method performs comparably to the state-of-the-art gender classification and/or age estimation methods with respect to accuracy and runs fast enough (average 14fps) on a Jestson Nano embedded board.

• 센서학회지
• /
• 제14권4호
• /
• pp.237-243
• /
• 2005

Strain gauge type load cell is used widely as weight sensor. However, it has problems such as noise, power consumption, high cost and big size. Semiconductor type piezoresistive pressure sensor is practically used in recent for low hysteresis, good linearity, small size, light weight and strong on vibration. In this paper, we have fabricated the piezoresistive pressure sensor and packaged the miniature weight sensor. We packaged the miniature weight sensor by flip-chip bonding between die and PCB for durability, because the weight sensor is directly contacted on a physical solid distinct from air and oil pressure. We measured the characteristics of the weight sensor, which had the output of $10{\sim}80$ mV on the weight range of $0{\sim}2$ kg. In the result, we could fabricate the weight sensor with an accuracy of 3 %FSO linearity.

• 한국음향학회지
• /
• 제43권2호
• /
• pp.200-206
• /
• 2024

음악 유사도 계산은 음악 검색 서비스 구현에서 중요한 구성 요소 중 하나이다. 본 논문은 커버곡 검색 성능을 제고하기 위해서, 크로마그램 벡터 별로 커버곡 검색 적합도를 구하여 음악 유사도 계산 시 가중치로 활용한다. 커버곡 검색 적합도는 확률 적합도 모델을 이용하여 구한다. 커버곡 검색에 도움이 될 수 있는 분별도가 높은 벡터에 높은 가중치를 부여하고, 흔하게 존재하여 분별도가 떨어지는 벡터에 낮은 가중치를 부여하는 방식으로 음악 유사도 함수를 유도한다. 두 가지 커버곡 실험 데이터셋에서 성능 비교를 수행하여 제안한 음악 유사도 함수가 커버곡 검색 성능을 개선시킬 수 있음을 보였다.

• 한국군사과학기술학회지
• /
• 제16권5호
• /
• pp.646-652
• /
• 2013

PRA(Position Reporting Accuracy) for EO/IR(Electro-Optic/Infrared) airborne camera is an important factor in geo-pointing accuracy. Generally, rate table is used to measure PRA of gimbal actuated camera like EO/IR. However, it is not always possible to fix an EUT(Equipment for Under Test) to rate table due to capacity limit of the table on the size and weight of the object(EUT). Our EO/IR is too big and heavy to emplace on it. Therefore, we propose a new verification method of PRA for airborne camera and assess the validity of our proposition. In this method we use collimator, angle measuring instrument, 6 dof motion simulator, optical surface plate, leveling laser, inclinometer and poster(for alignment).