• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.25 no.1
• /
• pp.99-107
• /
• 2014

Abruptly occurred obstacles on highway threaten driving safety. Radar draws the attention to the collision avoidance system because it can be fully operational in all weather, and day and night condition. This paper presents the design, implementation and performance test results of pulsed Doppler radar system for detection and warning of road obstacles. The system is designed to consider highway environment and detection capability about various fixed and moving obstacles. The system consists of 4 subsystems, which include antenna unit, transmitter and receiver unit, radar signal & data processing unit, and controller & display unit. The core technologies include clutter map based change detection for fixed obstacles detection, Doppler estimation for velocity detection of moving targets, and azimuth angle estimation method using monopulse for lane estimation and tracking. The design performance of the developed radar system is verified through experiments using a fixed reference target and moving vehicles in test highway.

• Journal of the Society of Naval Architects of Korea
• /
• v.58 no.5
• /
• pp.281-293
• /
• 2021

Oil and steel prices, which are major pricescosts in the shipbuilding industry, were predicted. Firstly, the error of the moving average line (N=3-5) was examined, and in all three error analyses, the moving average line (N=3) was small. Secondly, in the linear prediction of data through existing theory, oil prices rise slightly, and steel prices rise sharply, but in reality, linear prediction using existing data was not satisfactory. Thirdly, we identified the limitations of linear prediction methods and confirmed that oil and steel price prediction was somewhat similar to actual moving average line prediction methods. Due to the high volatility of major price flows, large errors were inevitable in the forecast section. Through the time series analysis method at the end of this paper, we were able to achieve not bad results in all analysis items relative to artificial intelligence (Prophet). Predictive data through predictive analysis using eight predictive models are expected to serve as a good research foundation for developing unique tools or establishing evaluation systems in the future. This study compares the basic settings of artificial intelligence programs with the results of core price prediction in the shipbuilding industry through time series prediction theory, and further studies the various hyper-parameters and event effects of Prophet in the future, leaving room for improvement of predictability.

• Journal of Acupuncture Research
• /
• v.20 no.4
• /
• pp.24-41
• /
• 2003

Objective: Dopamine activity in thenucleus accumbens is an important neuropharmacological component of morphine reinforcement. In this nucleus a shell and core have been distinguished on the basis of anatomical and neurochemical criteria. Although acupuncture has been standard intervention in many detoxication programs worldwide, the central mechanism by which morphine acts to reinforce behavior remain elusive. The present in vivo microdialysis study was conducted, in freely moving rats, to detect the effects of acupuncture on extracellular dopamine release in the nucleus accumbens. Methods: Male Sprague-Dawley rats received acupuncture for 1 min after injection of morphine hydrochloride (5mg/kg, s.c.). The employed acupuncture needle points corresponded to bilateral Neiguan(PC6) on the pericardium channel, which has been used to treat mental and psychosomatic disorders. Extracellular dopamine and its metabolites were measured every 20 mins for 3 hrs following the subcutaneous morphine injection. Results: Results showed that acupuncture at PC6 significantly attenuated increases in dopamine levels induced by a single acute morphine injection in the nucleus accumbens shell and core, respectively. Conclusions: These results provided strong evidence for acupuncture-mediated reduction in morphine-induced dopamine release in the rat nucleus accumbens.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.113-116
• /
• 2003

To maximize the productivity in machining molds and dies, machine tools should operate at high speeds. During the high speed operation of moving frames or spindles, vibration problems are apt to occur if the machine tool structures are made of conventional steel materials with inferior damping characteristics. However, self-excited vibration or chatter is bound to occur during high speed machining when cutting speed exceeds the stability limit of machine tool. Chatter is undesirable because of its adverse effect on surface finish, machining accuracy, and tool lift. Furthermore, chatter is a major cause of reducing production rate because, if no remedy can be found, metal removal rates have to be lowered until vibration-free performances is obtained. Also, the resonant vibration of machine tools frequently occurs when operating frequency approaches one of their natural frequencies because machine tools have several natural frequencies due to their many continuous structural elements. However, these vibration problems are closely related to damping characteristics of machine tool structures. This paper presents the use of polymer concrete and sandwich structures to overcome vibration problems. The polymer concrete has high potential for machine tool bed due to its good damping characteristics with moderate stiffness. In this study, a polymer concrete bed combined with welded steel structure i.e., a hybrid structure was designed and manufactured for a high-speed gantry-type milling. Also. its dynamic characteristics were measured by modal tests.

• Design & Manufacturing
• /
• v.10 no.2
• /
• pp.29-33
• /
• 2016

Production machines have been more important, due to quality level of vehicle motor core is getting higher. That is why, to improve assembly fit of tooling and to be emphasized how much moving down caused of deterioration of high speed press, it is also getting more important parts as solution of problems. To analyze how much move based on condition of movement as tooling and high speed press, and to measure how much impact to embossing height caused of changing movement down. As the result of investigation, in case of material thickness 0.5mm, there is highest pull and force power when emboss height is 0.45mm. If emboss height is less than 0.45mm, pull and force power is getting lower, if emboss height is higher than 0.45mm, it is impossible to make it forming caused of changed press movement, also it has been piercing.

• Nuclear Engineering and Technology
• /
• v.55 no.12
• /
• pp.4477-4490
• /
• 2023

Fuel locking mechanisms (FLMs) are essential in upward-flow research reactors to prevent accidental fuel separation from the core during reactor operation. This study presents a novel design concept for a remotely controlled plate-type nuclear fuel locking mechanism. By employing electromagnetic field analysis, we optimized the design of the electromagnet for fuel unlocking, allowing the FLM to adapt to various research reactor core designs, minimizing installation space, and reducing maintenance efforts. Computational flow analysis quantified the drag acting on the fuel assembly caused by coolant upflow. Subsequently, we performed finite element analysis and evaluated the structural integrity of the FLM based on the ASME boiler and pressure vessel (B&PV) code, considering design loads such as dead weight and flow drag. Our findings confirm that the new FLM design provides sufficient margins to withstand the specified loads. We fabricated a prototype comprising the driving part, a simplified moving part, and a dummy fuel assembly. Through basic operational tests on the assembled components, we verified that the manufactured products meet the performance requirements. This remote-controlled micro locking mechanism holds promise in enhancing the safety and efficiency of plate-type nuclear fuel operation in upflow research reactors.

• Cartoon and Animation Studies
• /
• s.43
• /
• pp.1-22
• /
• 2016

So far, the Studio Ghibli's major masterpieces, and have been studied extensively from mythical and psychological perspectives due to the films' intrinsic symbolism within their characters and events. However, there have been insufficient in-depth research on the types of love the two works have. Therefore, this study will focus on how the types of love in the two animations mirror the concept of love in Plato's theory of Eros through the analysis of two films' characters. The desire for memory and recovery can be seen in , and glimpses of each phase of aim towards changes in physical appearance can be shown in . These describe the function and the purpose of Eros that Plato states in Socrates' terms in Phaedrus and Symposium. Plato ultimately defined Eros as a spirit that leads to the world of Ideas and suggested the five stages of love that are divided in accordance with the ultimate purpose and attitude of mankind towards Eros. The cognition area, changes in appearance of the characters and spatial ranks in and critically reveal such core concepts of the theory of Eros. It is noteworthy that the two works show the origin of the most universal ideology of the West. These two animation films are particularly significant in terms of that they reflect the western epistemology while covering exclusive and covert ethnic emotions.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.16 no.6
• /
• pp.1064-1074
• /
• 1992

Eliminating the under-cut caused by interference between a mold and a product in designing a mold for in jection molding processes is a very important problem. In general, the under-cut problem can be avoided by side cores which are the principal members of a mold assembly. In this research, a procedure has been developed by which the side cores and the corresponding core and cavity plates of a mold are generated after identifying the mold faces preventing product faces from moving while being discharged. The characteristic features of the procedure suggested in this paper are as follows. One is that the interference faces between the product and the mold are derived only from the core plate(or cavity plate) alone without considering the product together. The other is that the algorithm in the designing of side cores and modifying molds, is very efficient because it uses Euler operations instead of Boolean operations.

• Journal of Magnetics
• /
• v.20 no.3
• /
• pp.273-283
• /
• 2015

In this study, we propose an analytical model for studying magnetic fields in radial-flux permanent-magnet eddy-current couplings by considering the effects of slots and iron-core protrusions on the eddy currents. We focus on the analytical prediction of the air-gap field by considering the influence of eddy currents induced in conducting bars. In the proposed model, the permanent magnet region is treated as the source of a time-varying magnetic field and the moving-conductor eddy current problem is solved based on the resolution of time-harmonic Helmholtz equations. The spatial harmonics in the air gap and in slots, as well as the time harmonics are all considered in the analytical calculation. Based on the proposed field model, the electromagnetic torque is computed by using the Maxwell stress tensor method. Nonlinear finite element analysis is performed to validate the analytical model. The proposed model can be used for permanent-magnet eddy-current couplings with any slot-pole combination.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.24 no.6
• /
• pp.566-572
• /
• 2004

It is necessary to measure the direct current with a non-contact methodology for the liquid or gas phase, as welt as the conducting metals. This paper described a theoretical consideration and experimental verification for a non-contact quantitative direct current measurement system using the Faraday effect and magnetic flux leakage. The leakage of magnetic flux occurs around a gap when a ferromagnetic core including the discontinuous gap is magnetized. Two large anisotropic domains in a magneto-optical film are occurred by the vertical component of leaked magnetic flux and the domain walls are paralleled to the center of the gap. Here, the symmetrical arrangement of domains are deflected when a vertical magnetic field is applied to the magneto-optical film. The domain wall of the magneto-optical film are relocated when a measuring current passes through the ferromagnetic core. Therefore, a direct current passing through the core can be determined quantitatively by the measurement of moving distance of the domain wall.