Earticle

The role of QR Code robots in smart logistics is great. Cognitive robots, such as logistics robots, were mostly used to adjust routes and search for peripheral sensors, cameras, and recognition signs attached to walls. However, recently, the ease of making QR Codes and the convenience of producing and attaching a lot of information within QR Codes have been raised, and many of these reasons have made QR Codes recognizable as visions and others. In addition, there have been cases in developed countries and Korea that control several of these robots at the same time and operate logistics factories smartly. This representative case is the KIVA robot in Amazon. KIVA robots are only operated inside Amazon, but information about them is not exposed to the outside world, so a variety of similar robots are developed and operated in several places around the world. They are applied in various fields such as education, medical, silver, military, parking, construction, marine, and agriculture, creating a variety of application robots. In this work, we are developing a robot that can recognize its current position, move and control in the directed direction through two-dimensional QR Codes with the same horizontal and vertical sides, and the error is to create a QR Code robot with accuracy to reach within 3mm. This paper focuses a study on the application of QR Code position recognition during the development of QR Code-aware indoor mobility robots.

Hydrogen is one of the main candidates in replacing fossil fuels in the forthcoming years. However, hydrogen technologies must deal with safety aspects due to the specific sub�stance properties. This study aims to provide an overview on the loss of mechanical properties of cryogenic materials, which may lead to serious consequences, such as fires and explosions. The hydrogen embrittlement of cryogenic steels was investigated through slow strain rate tensile tests (SSRTs) and thermal desorption analyses of electrochemically H-charged specimens. As a prior study to confirm mechanical properties under liquid hydrogen conditions, the amount of diffusive hydrogen that causes hydrogen embrittlement was confirmed after charging hydrogen using an electrochemical method for 4 types of steel materials applied as cryogenic materials did. When exposed to the same hydrogen charging conditions, the amount of hydrogen diffused into the 9% nickel steel is the highest compared to the austenitic steel type. It is considered that this is because the diffusion and integration of hydrogen into the interior is easy. It is necessary to analyze the relationship between hydrogen loading and mechanical properties, and this will be carried out in a follow-up study.

This study indirectly measures the vibration value corresponding to the abnormal vibration generated by the small engine for light aircraft to which the dual carburetor is applied by the pressure difference from each carburetor. It relates to a system for outputting a warning to a pilot, comprising two pressure gauges for measuring the pressure from each carburetor and a warning signal output unit for outputting a warning signal corresponding to the pressure difference measured by the two pressure gauges do.

This paper studies the flow characteristics inside the low-temperature carbonization(LTF) including sealing chamber with labyrinth. The flow behavior inside the furnace was analyzed according to different labyrinth shapes. The effects of labyrinth baffle number, and clearance between upper and lower baffles in the sealing chamber were investigated. The large vortex and stagnation region are generated in the chamber when the gap between the baffle and baffle is small. As a result, the gas discharge flow rate can be increased by 29.4% when the flow space of labyrinth is made 75% of the baffle length.

In this paper, design of a recumbent bicycle for loading cargo is introduced as an application example of practical engineering. This device consists of a main frame due to the main load, an occupant seat considering the human body structural condition, a steering device(handle), a power transmission device (gear/chain, pedal, and crank), and a braking device (disk brake). In order to design and manufacture of the device, various subjects learned during the school year are reviewed and practiced. In particular, by designing the shape considering the load acting on the recumbent and the structural conditions of the human body, it is possible to understand the detailed mechanical mechanism as well as the understanding for the basic design. Through this case study, students can develop and enhance their creativity and practical skills for related industries by designing and manufacturing a real recumbent bike and, if necessary, industrializing these skills.

As the spread of new and renewable power generation facilities, the fixed investment cost CAPEX(Capital Expenditure) of solar power generation facilities decreases due to continuous technological development, and the impact of O&M costs that determine investment success has increased. For this reason, the importance of technologies such as accuracy of O&M cost calculation through ICT, failure prediction, and predictive maintenance have emerged. In the above paper, based on the cost-breakdown structure design and failure rate model design of the solar power generation facility using engineering estimation method, the maintenance cost of the solar power generation facility, which is a renewable power generation facility, is predicted and the maintenance cost used was compared and confirmed. In addition, the cost-breakdown structure and failure rate model of solar power generation facilities were designed and developed by incorporating them into a new program of economic evaluation of new and renewable power generation facilities.

In order to study the drying performance of the dryer, the performance characteristics of the heat pump dryer applied a PF heat exchanger is applied were experimentally investigated. The capacity, COP, drain and SMER of the dryer were measured by the refrigerant charge and EEV opening. Heat pump dryers are refrigerant-air systems. For the dryer performance test, an air enthalpy calorimeter was used. From the experimental results, the heat exchanger performances according to the change in the refrigerant charge and EEV opening were the maximum at 0.5kg refrigerant and 30% EEV opening, respectively. In addition, SMER suggested a satisfactory level of drying performance. This shows that the refrigeration cycle of the dryer must be operated at an appropriate refrigerant amount and EEV opening degree to secure optimal drying performance. On the other hand, the time to reach the target setting temperature of the dryer was increased by about 2.5 times depending on with/without the sample.

Considering the features of body repair for automotive body where same damage and repair conditions does not exist in car accident, it is essential to acquire know-how and continuously approach new materials and new technologies on the site of maintenance where the theoretical instruction of textbook cannot react accurately minute by minute. Especially, in case of car repair from unexpected accidents such as body repair or dent repair, it is difficult to satisfy vehicle owners despite their request. Accordingly, this study researched the better maintenance technology to restore to its original state with more improved technology as vehicle owners wish. This study made time to repair reduced by 98% and the cost reduced by 79.6% through the accurate diagnostic technique before repair and maintenance technologies of body crash analysis applying property of high-speed tensile. It also obtains intangible effects including prevention of environmental pollution and maximization of vehicle owners satisfaction.

This research propose a vehicle attitude estimation method using sensor fusion of speedometer and six-axis inertial sensor. External acceleration generated in a dynamic environment such as high-speed movement of a vehicle causes a considerable error in the attitude angle measured by the accelerometer. The external acceleration is estimated using velocity data obtained from speedometers mounted on most vehicles. The vehicle velocity is decomposed into three vector components using the angular velocity and attitude angle measured by the inertial sensor in the previous time step. The attitude angle estimated by the speedometer and the accelerometer is used to correct the error of the gyro sensor in the Kalman filter. In order to verify the performance of the proposed algorithm, experiments on a scenario of rapid acceleration/deceleration of a truck in a straight section and a scenario of high-speed driving on a long-distance highway are conducted.

In general, small and medium-sized computer rooms do not have access floors for reasons of increased floor height and increased construction cost. Therefore, the air conditioning method used here applies the method of directly blowing the cold air of the air conditioner into the computer room. In this case, the hot/cold air is not separated, and as the hot air is recirculated, it is re-introduced to the front of the server rack, resulting in a problem that the server cooling efficiency is decreased. In addition, in such a computer room structure, it is difficult to configure and install a containment system. In this study, we tried to understand the problem of the formation airflow in the case of using the existing air conditioning method, and to find a method of configuring the air conditioning environment to improve the cooling efficiency. The purpose of this study was to understand the airflow/temperature distribution in the computer room using the CFD simulation method. In addition, the thermal characteristics of various air-conditioning environments such as the location of the CRAC cold air discharge location, the layout between server rack and CRAC and the containment were reviewed.

In order to develop a 1 ton truck rear wheel air suspension module, this study designed and manufactured a Z-type spring and air suspension module test jig to optimize the design and reliability of the Z-type spring and vibration-free air suspension module, which are core parts, and to secure the reliability of the developed parts. We were able to achieve the technology development goal of this thesis by making a prototype and conducting a test evaluation at an external test and research institute to perform the vibration endurance test aimed in this study.

In this study, the Euro NCAP-based AEB system evaluation simulation was conducted by applying the calculated corrected TTC by road condition estimation of scenarios (CPFA, CPNC, CPLA) of the V2P situation scenario using PC-Crash, a program used for traffic accident analysis. The scenario was evaluated in consideration of the two road conditions. the low-speed conditions among every scenarios avoided collision, but in the medium and high-speed conditions has been collided with pedestrian. It was confirmed that the time point at recognizing pedestrian was lower than set TTC at which AEB system was operated, even though the AEB was operated immediately, a collision occurred due to insufficient braking distance. As in this study, if studies such as V2V, V2P, and V2B considering road friction are actively conducted, it is expected to be useful data for automobile accident prevention and accident analysis.

This study was to develop a piston rod made of SiC by applying a sintering treatment after press molding in order to replace the imported piston rod used in the past. As a result of evaluating the mechanical properties of the developed piston rod, the following conclusions were obtained. The surface roughness value of the piston rod made of silicon carbide was 0.950Ra, and the surface Vickers hardness value was 19.94GPa. As a result of XRD analysis of the surface of the prototype piston rod, the main crystalline phase was 6H-SiC, and the crystalline phases of 4H-SiC and α-SiC were existed. In addition, a trace amount of SiC was detected. As a result of SEM observation of the piston rod surface of the prototype, a number of large porosity were observed. As a result of measuring the surface hardness of the piston rod made of SiC, it showed 70% of the physical properties compared to imported products.

In applying LCD to TV application, one of the most significant factors to be improved is image sticking on the moving picture. Despite the development of technology for fast screen signal processing, it is very difficult to compose a high-quality screen due to the limitation of blinking driving due to the long afterglow time of the backlight. As the Single-LVDS signal system evolves from the Quad Signal Package to respond to 3D, the problem of processing faster signals within a set time is occurring. is becoming In this study, the aim was to realize this operation within 1 frame time by using the blinking backlight, and the existing cold cathode tube lamp was used as the light source. In general, cold cathode tube lamps have a long afterglow time of green, which is responsible for the main emission wavelength, so it is difficult to realize the above characteristics. A backlight capable of flickering within the time frame of the video frame was manufactured, and by using it, it was possible to confirm the effect of resolving the afterimage in a moving image by leaps and bounds.

Recently, as the demand for a non-contact liquid crystal alignment method capable of improving viewing angle characteristics has spread throughout the industry, various non-contact liquid crystal alignment methods, including conventional UV light alignment, are being actively studied. In the case of UV light alignment, it is currently applied to mass production in many fields and shows relatively excellent initial characteristics, but there is a problem of display quality deterioration over time. In this study, among these non-contact liquid crystal alignment methods, the liquid crystal is oriented by quantitatively irradiating an ion beam onto the SiOF inorganic film, which has excellent initial characteristics and does not cause deterioration in quality over time., the electro-optical properties were evaluated by manufacturing a commercial-level IPS (In-Plane Switching) liquid crystal cell. In particular, in the case of such inorganic film orientation, it is common to have many problems with orientation stability, but the evaluation cell manufactured by the method proposed in this study is capable of maintaining a uniform orientation without losing orientation even after heat treatment at a high temperature of 200°C. could be observed.

A wire rod, a material for multistage cold forging, is subjected to spheroidization and low annealing heat treatment to secure formability, and a phosphate coating treatment on the material surface to secure lubricity. The film layer produced by the phosphate treatment process is involved in adhesion to the material surface, adhesion to the forging die surface, and lubricity. This results in the increase or decrease of the forming load and the increase or decrease of the die life in the cold forging process. In particular, as the cold forging process progresses, the phosphate film is damaged and the original performance is deteriorated, so there is a high possibility of process defects. In case of excessive damage, the film is completely lost and die soldering occurs. Therefore, in this study, quantitative criteria for phosphate film damage are presented and the effect on the cold forging process is analyzed based on this to improve process analysis prediction accuracy. Therefore, in this study, quantitative criteria for phosphate film damage are presented, and based on this, the friction coefficient in the multi-stage cold forging process is to be derived.

This paper is a study to improve the energy harvesting output of a TENG(Triboelectric nanogenerator) driven by wind power using fine PTFE(Polytetrafluoroethylene) flakes. The structure of the nanogenerator was manufactured in the cylindrical structure, Al(Aluminium) was attached to the inner wall of the cylinder and the PTFE flakes were rotated by the wind inside the cylinder. The number of contact and separation motions was increased as there are multiple PTFE flakes, resulting in improvement of the harvesting output. Through this, it was evaluated to the energy harvesting output characteristics according to the change in the number of PTFE flakes. Up to the optimum, the energy collection efficiency shows the linear correlation with the increase in PTFE flakes and decreases after that. As the PTFE flakes are more than the optimum, the lowering in the harvesting output is induced by obstructing the flow of wind inside the cylinder.

In modern times, where problems due to environmental pollution are continuously occurring, hydrogen is in the spotlight as the energy of the future. Hydrogen is an eco-friendly energy resource that does not even generate CO2, and is actively supporting research to utilize hydrogen energy at the national level. This study is a study on the cryogenic mechanical properties of the elements constituting the cargo hold during the transportation of liquid hydrogen. Among the various components, the evaluation of mechanical properties of the cryogenic adhesive under liquid helium conditions was confirmed. The related contents are summarized as follows. As a result of performing SSRT by curing the adhesive, it was confirmed that tensile strength and maximum strain were increased at cryogenic temperature (-230°C) compared to room temperature (25°C). It was confirmed that the adhesive-hardened specimen showed a brittle fracture mode at both room temperature and cryogenic temperature during tensile. Improvements in this study, such as pores occurring during adhesive curing, the use of standard specimens, and experiments at -253°C, the boiling point of hydrogen, exist, and are planned to be carried out in subsequent studies.

This paper considers the influence of internal heat exchanger and capillary tube on the efficiency of small refrigeration system using eco-friendly refrigerants such as R290, R600a, R1270, and R717. A refrigeration system using such internal heat exchanger and capillary tube may improve performance, but may degrade performance. Therefore, this paper used a mathematical model in a normal state to understand performance characteristics as to what change occurs when internal heat exchanger and capillary tube are attached to eco-friendly refrigerant based on R134a. In addition, the effects of operating conditions such as refrigerant flow rate, evaporation temperature, condensation temperature, subcooling degree internal heat exchanger length and capillary tube length were analyzed. The result showed that the evaporation temperature, condensation temperature, subcooling degree, internal heat exchanger length and capillary tube length had an effect on the refrigeration capacity and compression power. Therefore, it is necessary to design a refrigeration cycle using an eco-friendly refrigerant by grasping these effects in detail.

In this paper, 1kW prototype PCS for tidal power generation system, which is attracting attention as the next-generation renewable energy, is studied. Tidal power generation is a method of producing energy using the difference between the tides. The advantage of tidal generators is that, unlike other renewable energies such as wave power, wind power, and solar power, they are relatively less affected by the weather changes and are regularly produced at regular intervals.

In this study, the analysis of the unsteady viscous flow field using the uRANS equation in a moving mesh was studied. The simulation domain is composed of an overset zone fixed to a propeller and rotating at a constant angular speed and a far zone which is located in the far distance and does not move. Each zone is composed of a polyhedral meshes for the accurate and robust gradient calculation in addition to the reduction of computation time. Simulation technique was applied to the aerodynamic analysis of the 5-inch propeller and compared with those of the MRF and the thrust test. The thrust predicted by the moving mesh showed good correlation with the MRF result within 0.5% difference, but the torque showed a tendency to under-prediction by about 10% compared to the MRF. In the future, we plan to further validate the numerical analysis technique using the moving mesh by applying it to the configurations in which precise test results exist.

Numerical analysis has been carried out to investigate the characteristics of seawater flow fields and turbine output in a compact double current tidal power generation system for various level differences. There are growing concerns for the development of efficient tidal power generation which is stable and less affected by environmental circumstances as ocean energy. Especially the flow field characteristics in the compact tidal power generation system have a large influence on the system power generation performance. Flow velocity, pressure, and streamline distributions are compared including vertical type turbine out, and it can be predicted that seawater is accelerated by vortex flow in front of the turbine and there is severe turbine output variation due to the water level difference with pressure difference. These results can be applied as basic data for the effective development of compact tidal power generation system.

This study presents a numerical modeling and a transient simulation of a desiccant coated heat exchanger (DCHE) that is employed for dehumidification in buildings. DCHE is fabricated by coating type RD silica gel on the fin surfaces of a fin tube heat exchanger. The latent cooling load, which is 25 to 45% of the total cooling load in most weather conditions is removed by adsorption of vapor using DCHE. The saturated adsorbent is then regenerated by using either low-temperature waste heat from industry and/or renewable energy such as solar energy and geothermal energy. A mathematical model is established and a transient simulation has been carried out so as to analyze its performance in terms of average humidity difference (AHD), moisture removal capacity (MRC), latent cooling capacity(QL), and COP. Comparison between the simulation results and the experimental data was carried out and showed good agreement and a similar trend with a maximum discrepancy of 5%. Key results revealed that MRC, AHD, QL, and COP are largely affected by both air dry-bulb temperate and air wet-bulb temperature while they are less affected by the frontal air velocity. Furthermore AHD, MRC and QL are largely improved by hot-water temperature while COP decreases as hot-water temperature increases due to high regeneration energy consumption.

The role of QR Code robots in smart logistics is great. Cognitive robots, such as logistics robots, were mostly used to adjust routes and search for peripheral sensors, cameras, and recognition signs attached to walls. However, recently, the ease of making QR Codes and the convenience of producing and attaching a lot of information within QR Codes have been raised, and many of these reasons have made QR Codes recognizable as visions and others. In addition, there have been cases in developed countries and Korea that control several of these robots at the same time and operate logistics factories smartly. This representative case is the KIVA robot in Amazon. KIVA robots are only operated inside Amazon, but information about them is not exposed to the outside world, so a variety of similar robots are developed and operated in several places around the world. They are applied in various fields such as education, medical, silver, military, parking, construction, marine, and agriculture, creating a variety of application robots. In this work, we are developing a robot that can recognize its current position, move and control in the directed direction through two-dimensional QR Codes with the same horizontal and vertical sides, and the error is to create a QR Code robot with accuracy to reach within 3mm. This paper focuses a study on the driving directions of QR Code-aware movable robots during the development of QR Code-aware indoor mobility robots.

In this paper, a heat exchange system using cooling dehumidification and mixing process was proposed as an experimental study for a white smoke reduction heat exchanger system under winter condition. The white smoke reduction heat exchange system is divided into an EA part, SA part, W part and mixing zone. For the operating conditions, three types (Cases 1, 2, and 3) were selected depending on whether EA fan, SA fan, and A-W heat exchanger were operated. In addition, in order to visualize the white smoke exhausted from the mixing zone, it was photographed using CCTV. In order to investigate the performance of the white smoke reduction heat exchange system, the temperature reduction rate and absolute humidity reduction rate of EA and the heat recovery rate of W were calculated. The temperature change of EA and SA according to operating conditions was most effective in Case 3, and the temperature and absolute humidity at the outlet of the mixing zone were greatly reduced. From the results of the white smoke visualization, it was confirmed that the white smoke generation mechanism was different depending on the operating conditions, and the amount of white smoke generation was greatly reduced.

In this study, controlling pattern gap was induced by deformation of the stretchable substrate. The pre-fabricated pattern was made by depositing an Au(gold) on the Si substrate, and PDMS(Polydimethylsiloxane) was used for the stretchable substrate in consideration of surface energy, formability, and viscoelastic characteristics. For uniform deformation of PDMS, it is manufactured in the form of a tensile specimen using a molding method. An external force is applied to the deformable substrate in the uni-axial direction using a self-manufactured JIG, and the Au thin film pattern is transferred to the substrate under tensile state. After that, the external force is removed, and the PDMS specimen is recovered to its initial state. At this time, it can be seen that the pre-fabricated pattern gap is shortened from the initial size due to the viscoelastic properties of the PDMS. As a result, it was characterized to deformation rate of the pattern gap according to elongation rate of PDMS.

Noise is a sound that humans do not want. In this study, Based on the Rotax 912 engine, which is most commonly used in Korea, we will look at noise and thrust changes by changing the propeller blade angle by 1 degree for the two-blade Sensenich Propeller and the three-blade Wrap drive Propeller. Through this, we want to check which part of the propeller angle produces the least noise and the least thrust loss for each propeller, and propose a propeller operation plan in a noisy area based on the value.

Magnetic abrasive finishing process is one of the advanced finishing technique, which is commonly used to improve the surface accuracy and dimensional of many products in various application such as for medical implant, automotive, electrical, and IT, etc. In this study, the MAF process using rotating magnetic field with flexible processing force is used to smooth the surface of STS 316L stents wire under the optimal conditions such as rotating speed: 150, 350, 600rpm; diamond grain size: 1, 3, 6-μm, and processing time: 20, 40, 60, 80min. The results showed that under the processing conditions, quality enhancement in surface accuracy of STS 316L stent wire is achieved, in which the surface roughness is reduced from 0.22 to 0.06-μm.

We need data such as the number of lanes for lane change on the road as well as environmental and object recognition of the road for the autonomous vehicle of the future. This study proposed an algorithm that recognizes the left and right lanes and the center lane while driving differently from the black box image taken from a car. In general, deep learning does not recognize lanes individually but recognizes all lanes as only one lane. Therefore, using YOLO's object recognition function, the left and right lanes and the center lane were detected as different lanes, and a heuristic method was applied to recognize multi-lanes as more correct lanes. As a result of the performance evaluation, we confirmed that the proposed method detects the lane more accurately than Fast R-CNN and only YOLOv2.

This study aimed to develop an algae reduction device using bubbles to improve algal blooms occurring in lakes or reservoirs in summer, and to design a venturi, a major core device for bubble generation and supply. As a measure to improve the bubble generation effect of the venturi, the venturi was devised to change the air intake characteristics, and the flow characteristics were analyzed through CFD simulation to achieve the optimal design.