Fuzzy system based human behavior recognition by combining behavior prediction and recognition

Batchuluun, G.,Kim, J.H.,Hong, H.G.,Kang, J.K.,Park, K.R. Pergamon 2017 Expert Systems with Applications Vol. No.

With the development of intelligent surveillance systems, human behavior recognition has been extensively researched. Most of the previous methods recognized human behavior based on spatial and temporal features from (current) input image sequences, without the behavior prediction from previously recognized behaviors. Considering an example of behavior prediction, ''punching'' is more probable in the current frame when the previous behavior is ''standing'' as compared to the previous behavior being ''lying down.'' Nevertheless, there has been little study regarding the combination of currently recognized behavior information with behavior prediction. Therefore, we propose a fuzzy system based behavior recognition technique by combining both behavior prediction and recognition. To perform behavior recognition during daytime and nighttime, a dual camera system of visible light and thermal (far infrared light) cameras is used to capture 12 datasets including 11 different human behaviors in various surveillance environments. Experimental results along with the collected datasets and open database showed that the proposed method achieved higher accuracy of behavior recognition when compared to conventional methods.

폴리올레핀계 단성분 부직포 및 이성분 시스-코어 복합부직포의 열융착 거동에 관한 연구

최세진,이도준,이현석,김한성,Choi, Se Jin,Lee, Do Jun,Lee, Hyun Seok,Kim, Han Seong 한국섬유공학회 2017 한국섬유공학회지 Vol.54 No.2

In this study, we have investigated the difference between the thermal bonding behaviors of mono-component and sheath-core nonwoven fabrics used as hot-melt adhesives. The difference between the manufacturing processes and the melting points of the nonwoven fabrics lead to a difference in their thermal bonding behavior. This was confirmed through image analysis by observing the change in the thermal shrinkage and the pore size ratio with temperature. The difference in the behavior of the fibers is also explained by dynamic mechanical analysis. The analysis of the thermal bonding mechanism of the hot-melt nonwoven fabrics can be used as a supporting data for their manufacturing process in order to improve the performance of the hot-melt adhesives and the design adhesion strength.

터빈블레이드 형상 mock-up의 기하학적 배치조건에 따른 전자빔 물리기상증착법으로 제조된 7 wt% YSZ 열차폐 코팅의 코팅 균일성

오윤석,채정민,류호림,한윤수,안종기,손명숙,김홍규,Oh, Yoon-Suk,Chae, Jung-Min,Ryu, Ho-lim,Han, Yoon-Soo,An, Jong-Kee,Son, Myung-Sook,Kim, Hong-Kyu 한국결정성장학회 2019 한국결정성장학회지 Vol.29 No.6

전자빔 물리기상증착기술(EBPVD)은 주상형 성장거동과 같이 고온에서의 구조 안정성에 기여할 수 있는 특성으로 인해 터빈블레이드 등과 같은 항공기 엔진 고온부품의 열차폐 코팅(TBC) 제조기술로 개발되어 상용화된 기술이다. 전자빔 증착으로 열·기계적 특성이 상용화 가능한 수준에 만족하는 고품질 열차폐 코팅제조를 위해서는 성장거동, 균일두께형성 등과 같은 구조적 요소의 제어가 반드시 수반되어야 한다. 본 연구에서는 실품형상에 근사한 터빈 블레이드 mock-up에 대한 기하학적 코팅인자 조건에 따른 7YSZ(7 wt% 이트리아 안정화 지르코니아) 열차폐 코팅의 성장거동과 구조변화를 고찰하였으며, 전산모사 기법을 활용한 기하학적 코팅인자 조건에 따른 코팅성장거동 모델링을 수행하여 실제 코팅결과와 비교하였다. Electron beam physical vapor deposition (EBPVD) is a conventional method to fabricate thermal barrier coating (TBC) of high temperature airfoil engine parts, such as blade etc. for its high temperature structural stability from the nature of columnar growth behavior. For the high quality of TBC by EBPVD, the structural factors, such as growth behavior, thickness uniformity and so on, should be managed to obtain the coating which satisfied the required specifications of usable level of mechanical and thermal properties. In this study, the growth behavior and structure variations of 7YSZ (7 wt% yttria stabilized zirconia) coatings with different configurational deposition parameters for the specimens which have turbine blade shape mock-up were investigated. Growth behavior of coatings were studied by comparing computational modeling of evaporation behavior with actual deposition process using e-beam source.

A review on the failure behavior and countermeasures of thermal barrier coatings

Jiahang Liu,Zhe Lu,Yanwen Zhou,Jing Zhang,Guanlin Lyu 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.2

Thermal barrier coatings are widely used in high-temperature components in aircraft thrusters, power generation, and marineengines, enabling gas turbines to operate at elevated temperatures for extended periods by reducing the superalloys' surfacetemperature. During service, high-temperature oxidation, hot corrosion, and sintering occur inside the thermal barriercoatings, resulting in changes in the macro and microstructure of the coatings, and thermal-mechanical propertiesdegradation, eventually leading to coating failure. The main factors that lead to the failure of thermal barrier coatings andaffect the life of thermal barrier coatings are reviewed, including the formation of thermally grown oxides on the surface ofthe bond coat, the corrosion caused by the deposits on the surface of the coating and the sintering of the high-temperatureceramic layer, and the failure mechanism of the coating is analyzed. The countermeasures to prolong the service life of coatingsare reviewed from thermal barrier coating materials, coating structure, coating preparation methods, and post-treatment.

A cylindrical shell model for nonlocal buckling behavior of CNTs embedded in an elastic foundation under the simultaneous effects of magnetic field, temperature change, and number of walls

Timesli, Abdelaziz Techno-Press 2021 Advances in nano research Vol.11 No.6

This model is proposed to describe the buckling behavior of Carbon Nanotubes (CNTs) embedded in an elastic medium taking into account the combined effects of the magnetic field, the temperature, the nonlocal parameter, the number of walls. Using Eringen's nonlocal elasticity theory, thin cylindrical shell theory and Van der Waal force (VdW) interactions, we develop a system of partial differential equations governing the buckling response of CNTs embedded on Winkler, Pasternak, and Kerr foundations in a thermal-magnetic environment. The pre-buckling stresses are obtained by applying airy's stress function and an adjacent equilibrium criterion. To estimate the nonlocal critical buckling load of CNTs under the simultaneous effects of the magnetic field, the temperature change, and the number of walls, an optimization technique is proposed. Furthermore, analytical formulas are developed to obtain the buckling behavior of SWCNTs embedded in an elastic medium without taking into account the effects of the nonlocal parameter. These formulas take into account VdW interactions between adjacent tubes and the effect of terms involving differences in tube radii generally neglected in the derived expressions of the critical buckling load published in the literature. Most scientific research on modeling the effects of magnetic fields is based on beam theories, this motivation pushes me to develop a cylindrical shell model for studying the effect of the magnetic field on the static behavior of CNTs. The results show that the magnetic field has significant effects on the static behavior of CNTs and can lead to slow buckling. On the other hand, thermal effects reduce the critical buckling load. The findings in this work can help us design of CNTs for various applications (e.g. structural, electrical, mechanical and biological applications) in a thermal and magnetic environment.

공동주택 거실 온열 환경의 측정 및 거주자의 온도조절행위에 관한 연구

전정윤,김효진,배누리 대한건축학회 2005 대한건축학회논문집 Vol.21 No.8

This study measured the thermal environment and residents' control behaviors of a thermostat in the apartments' living rooms which used the floor heating system in winter in Seoul. The purpose of this study is to find out the present thermal environment of the living rooms and the problems of present heating systems and control methods and to suggest the devices for the improvement of human interface. The surveys and measurements took place in twelve apartments of Seoul for a week in February, 2004. The results were summarized as follows; The thermal environment of apartments' living rooms were slightly warm and dry, and residents showed low clo value compare to season. Furthermore, by the heating system, there were differences in residents' control behaviors. This is due to the method of calculating heating cost by the heating system and the usability of controller by the type of thermostats. Therefore, the conversion from the existing central heating system to the separate heating system and the improvement of thermostats' utility will be needed.

Influence of hydrodynamic parameters in plate heat exchangers in ice slurry transport

Jiménez Pacheco Hugo Guillermo,Milon Guzmán Juan José,Miranda Ramos Lilia Mary,Delgado Sarmiento Pavel Kewin,Linares Flores Castro Antonio Erick,Leal Braga Sergio 대한설비공학회 2023 International Journal of Air-Conditioning and Refr Vol.31 No.1

Ice slurry is applied in different refrigeration and air conditioning systems, and among its main advantages is the ability to store latent heat and be pumpable as cold water. This fluid can be used for thermal storage instead of cold water or solid ice, since, at certain concentrations, it can be pumped through heat exchangers. For this technology to be widely used, the equipment must be designed considering the heat exchange characteristics. This study developed an experimental system to study the parameters that influence heat exchange, using ice slurry in a plate heat exchanger and water as a thermal load. Several situations with different flows and initial fractions of ice in ice slurry were analyzed. The input conditions of the thermal load were kept constant, the temperature, the pressure drop and the flow of the ice slurry in the heat exchanger were controlled, according to the Nusselt, Prandtl, and Reynolds coefficients. Results show that the global heat exchange coefficient increases with the increase of the initial ice fraction; the cooling capacity of the heat exchanger increases when ice slurry is used as a fluid. For flow rates greater than 0.16 kg/s and ice fractions above 11%, ice crystals are generated at the heat exchanger outlet, due to the ice slurry’s higher viscosity, at approximately 0.003 Pa at the outlet, since the pressure drop increases as the initial ice fraction increases. Results show ice slurry thermohydraulic behavior. Its use shows favorable characteristics in heat exchange. Ice slurry is applied in different refrigeration and air conditioning systems, and among its main advantages is the ability to store latent heat and be pumpable as cold water. This fluid can be used for thermal storage instead of cold water or solid ice, since, at certain concentrations, it can be pumped through heat exchangers. For this technology to be widely used, the equipment must be designed considering the heat exchange characteristics. This study developed an experimental system to study the parameters that influence heat exchange, using ice slurry in a plate heat exchanger and water as a thermal load. Several situations with different flows and initial fractions of ice in ice slurry were analyzed. The input conditions of the thermal load were kept constant, the temperature, the pressure drop and the flow of the ice slurry in the heat exchanger were controlled, according to the Nusselt , Prandtl , and Reynolds coefficients. Results show that the global heat exchange coefficient increases with the increase of the initial ice fraction; the cooling capacity of the heat exchanger increases when ice slurry is used as a fluid. For flow rates greater than 0.16 kg/s and ice fractions above 11%, ice crystals are generated at the heat exchanger outlet, due to the ice slurry’s higher viscosity, at approximately 0.003 Pa at the outlet, since the pressure drop increases as the initial ice fraction increases. Results show ice slurry thermohydraulic behavior. Its use shows favorable characteristics in heat exchange.

The Influence of Excavation Damaged Zone on the Mechanical and Thermal Behavior of Cement Mortar Block around an Opening

이창수,이동근,전석원 대한토목학회 2013 KSCE JOURNAL OF CIVIL ENGINEERING Vol.17 No.6

To investigate the influence of Excavation Damaged Zone (EDZ) on the mechanical and thermal behavior, EDZ was artificially generated around an existing circular hole in a mortar specimen. By applying high compressive stresses on the boundaries of a specimen and repeating loading and unloading cycles, EDZ was generated around the hole. An engineering heater was installed at the hole and the temperature of the heater was maintained at 75°C during the tests. Tangential strains and temperature were monitored at several points around the hole and compared to those measured in the specimen without EDZ. For elliptical and circular damaged zones, the tangential strain in the EDZ increased by as much as 88% and 58%, respectively and temperature in the EDZ decreased by 2.8°C and 0.85°C, respectively. Two-dimensional thermal-mechanical coupled numerical simulation using Particle Flow Code 2D (PFC2D) was carried out to analyze and to demonstrate the experimental results. For the numerical simulation,thermal parameters were determined using the results obtained from sensitivity analyses by a factorial design method. The TMcoupled PFC2D modeling results indicated that significant changes in mechanical and thermal behavior were observed, when the elliptical and circular EDZ was considered. And that the laboratory test results were successfully reproduced.

Investigation of Temperature Dependent Cracking Behaviors of Asphalt Mixtures using the Modified Overlay Tester

Christopher Jabonero,곽평진,조윤호 한국도로학회 2017 한국도로학회 학술대회 발표논문 초록집 Vol.2017 No.10

The discontinuity movements of the Portland cement concrete (PCC) layer due to temperature fluctuations and traffic loading are primary causes of the reflection cracking in asphalt overlays. The thermal expansion and contraction of the discontinuities at the PCC layer induces tension at the bottom of the asphalt overlay layer creating excessive strains which causes cracking. The additional cyclic discontinuity movements from the thermal fluctuations and traffic loads propagates the cracks initiated until failure of the overlay layer. However, the crack behaviors of asphalt mixtures varies with temperature due to its viscoelastic property. As such, there is a need to investigate the cracking behavior of asphalt mixtures with varying temperatures and loading conditions. A modified overlay tester developed to evaluate the cracking resistance of asphalt mixtures in various loading directions and different confining temperatures was used to investigate the behavior of asphalt materials with various temperatures and loading conditions. The laboratory test was conducted in 2 segments. The first segment investigates the asphalt cracking behavior subjected to horizontal loading in 3 varying temperatures (10, 25 and 40C) which simulates the cyclic thermal contraction and expansion at the discontinuity. The second segment examines the cracking propagation of the asphalt mixture subjected to vertical loading in 3 varying temperatures. A load dissipation curve per loading cycle is generated in each test along with the images taken on the face of the specimen to monitor the crack propagation. Results have shown that asphalt mixtures undergo a 3-phase cracking behavior: initiation, propagation and failure. This is evident in the load dissipation curve when the initiation phase shows a rapid reduction of peak loads in first series of loading cycles which is followed by a slow and constant load reduction over a certain number of cycles. Failure occurs when there is a sudden decline in peak load and the percent reduction of the load is achieved. Figure 1 shows a fine dense grade asphalt mixture subjected to horizontal movement at 10C. Meanwhile, the load dissipation curve is further investigated by analyzing the images captured during testing. It can be seen that the first visible crack can be identified after 40 cycles which steadily propagates up to 600 cycles. However, between 600 and 700 loading cycles, there is a sudden dip in peak load which shows that at that the stage the crack has already propagated to the top of the test specimen as shown in Figure 2. Other tests have shown that the cracking patterns and load dissipation curves vary with different testing temperatures signifying that low temperature is more susceptible to early failure with constant differential movement. Further tests signify that using a general formula, parameters are calculated which refer to fracture properties of the material.

Thermal Shock Behavior of Porous Nozzles with Various Pore Sizes for Continuous Casting Process

Kim, Ju-Young,Yoon, Sang-Hyeon,Kim, Yoon-Ho,Lee, Hee-Soo The Korean Ceramic Society 2011 한국세라믹학회지 Vol.48 No.6

Thermal shock behavior of porous ceramic nozzles with various pore sizes for continuous casting process of steel was investigated in terms of physical properties and microstucture. Porous nozzle samples with a composition of $Al_2O_3$-$SiO_2$-$ZrO_2$ were fabricatedby adding various sizes of graphite as the pore forming agent. As the graphite size increased from 45~75 to 150~180 ${\mu}m$, both the resulting pore size and the flexural strength also increased. A thermal shock test was carried out at temperatures (${\Delta}$T) of 600, 700, 800, and 900$^{\circ}C$. Microstructure analysis revealed a small number of cracks on the sample with the largest mean pore size of 22.32 ${\mu}m$. In addition, increasing the pore size led to a smaller decrease in both pressure drop and elastic modulus. In conclusion, controlling the pore size can enhance thermal shock behavior.