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박지호,김동식 순천향대학교 부설 산업기술연구소 2021 순천향 산업기술연구소논문집 Vol.27 No.2
Goldman Sachs recently laid off 598 top talents, while Google and NASA established a singularity university. As we enter the era of the 4th Industrial Revolution, each company and university is nurturing talent for the age of artificial intelligence(AI). As factories and various facilities are automated and AI and the Internet of Things (IoT) enter homes and businesses, interest in automation is gradually increasing, and AI robots are replacing human jobs. Therefore, a study was conducted on the implementation of a sorting robot for smart factory automation. The hardware of the robot was realized using TETRIX, and it was configured to recognize the color of blocks and classify the object using NXT color sensors. The color sensor is used to determine the type of a block and a linetracer is to help figure out location, and the block was placed in the right place. The control program was implemented using LabVIEW, and the NXT was implemented to control the robot through the signal obtained from the color sensor.
Jiho Lee,Tae Sung Lee,Oh Jun Kwon,Haigun Lee,Tae Kuk Ko IEEE 2014 IEEE transactions on applied superconductivity Vol.24 No.3
<P>This paper deals with the low-pass filtering characteristic of the axial magnetic field of no-insulation and partial-insulation high temperature superconducting (HTS) coils carrying a dc-biased ac current. Recently, the no-insulation winding technique has been issued as a key technique to enhance the performance of HTS coils in terms of the overall current density, thermal stability, and mechanical integrity. In this paper, to verify the effect of time-varying external distortion on no-insulation HTS coils, an experimental analysis is carried on three HTS coils-insulation, no-insulation, and partial-insulation coils. To simulate the environment in which time-varying external distortion influences the HTS coils, a dc-biased ac current is carried by the HTS coils. The axial magnetic fields of no-insulation, partial insulation, and insulation HTS coils are experimentally tested and analyzed. When the coils carry a dc-biased ac current, the no-insulation and partial-insulation coils have a tendency to attenuate the high-frequency components and to act as a low-pass filter on the axial magnetic field; however, the insulation coil does not attenuate the high-frequency components of the axial magnetic field. The analysis of the experimental results can be useful data for the adoption of no-insulation and partial-insulation windings in superconducting applications.</P>
Self-Excited Instabilities of Two Interacting Lean-Premixed Flames with Asymmetric Swirl Number
Jiho Lee,Kyu Tae Kim 한국추진공학회 2021 Journal of Propulsion and Energy Vol.2 No.1
When several swirl-stabilized flames are narrowly spaced in a low-emission gas turbine combustor, neighboring flames will interact. Understanding the response characteristics of the interacting flames is essential to control the development of self-excited combustion dynamics. The present study is concerned in particular with the influence of swirl flow parameters – relative rotational direction and swirl number combination – on the system’s thermoacoustic response. Phase-resolved CH* chemiluminescence imaging, OH Planar Laser Induced Fluorescence (PLIF), acoustic pressure, and global heat release rate measurements were performed to study the flame dynamics subjected to co-rotating and counter-rotating swirl arrangements with symmetric and asymmetric swirl number distributions. These parameters were found to exert a remarkable influence on the development of self-excited combustion instability. Our results suggest that counter-rotating swirl configurations, in which adjacent tangential streams flow in the same direction in the interaction region, are more effective to limit the growth of the instability for all swirl number combinations. Instantaneous flame front images reveal that the counter-rotating swirl flame interaction causes the two adjacent flames to stabilize in both the inner and outer shear layers, leading to the formation of the well-known “M” structure. By contrast, the interaction induced by co-rotating swirl flow tends to disturb the flame anchoring at the outer shear layers of each flame, due to the emergence of a large-scale flame front deformation, even under unforced conditions. Impingement of two opposed tangential jets is thought to be linked to the generation of disturbances, which in turn affect stabilization mechanisms and the dynamics of two interacting swirl flames.
Jiho Jang,DOH C. SHIN 한국행정학회 2008 International Review of Public Administration Vol.13 No.1
In this study, we proceed on the assumption that where the rule of law prevails, parliament becomes the key institution of democratic governance. To transform delegative or limited democracy into a truly representative democracy, it is necessary to ensure not only vertical but also horizontal accountability. This study considers the horizontal dimensions of accountability in order to provide a fuller picture of the part that the Korean legislature has played during the course of democratic regime change. It examines the current process of economic policymaking under democratic rule, using evaluative data from the lawmakers who serve on the National Assembly Committee on Finance and Economy. The authoritarian “sunflower” model presented an extreme version of technocracy, featuring efficient decision - making mostly by technocrats with little or no consultation with other governmental and nongovernmental institutions, including the National Assembly. The current model has, on the other hand, moderated technocratic control such that technocrats formulate policies in consultation with other, more diverse interests. Obviously, this model falls far short of manifesting a fully democratic model of economic policymaking in which the president and elected lawmakers formulate policy jointly in the context of extensive consultation with civic groups and all other relevant governmental and non-governmental organizations and interests.
Transient cooling operation of multistage thermoelectric cooler (TEC)
Jiho Park,Sangkwon Jeong 한국초전도저온공학회 2021 초전도와 저온공학 Vol.23 No.3
A thermoelectric cooler (TEC) is promising as an alternative refrigeration technology for the sake of its inherent advantages; no-moving parts and refrigerant-free in its operation. Due to the compactness, reliability and excellence in temperature stability, TECs have been widely used for small cooling devices. In recent years, thermoelectric devices have been attractive technologies that not only serve the needs of cooling and heating applications but also meet the demand for energy by recycling waste heat. In this research paper, multistage TEC is proposed as a concept of demonstrating the idea of transient cooling technology. The key idea of transient cooling is to harnesses the thermal mass installed at the interfacial level of the stages. By storing heat temporally at the thermal mass, the multistage TEC can readily reach lower temperatures than that by a steady-state operation. The multistage TEC consists of four different sizes of thermoelectric modules and they are operated with an optimized current. Once the cold-part of the uppermost stage is reached at the no-load temperature, the current is successively supplied to the lower stages with a certain time interval; 25, 50 and 75 seconds. The results show the temperatures that can be ultimately reached at the cold-side of the lowermost stage are 197, 182 and 237 K, respectively. It can be concluded that the timing or total amount of the current fed to each thermoelectric module is the key parameter to determine the no-load temperature.
Searching for Antibacterial Materials to Extend the Shelf Life of Salted Fish
JiHo YANG,HyunJung LEE,Hyun Jin JO,Jung Hwan OH,Fatih KARADENIZ,Mi-Soon JANG,Chang-Suk KONG 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10
Natural seasonings are the recent trend in food industry to replace the synthesized seasonings due to consumer preference. However, unexpected results may occur in terms of sensory evaluation and physico-chemical properties such as reduced flavor and color change by adding natural seasoning. In this study, by evaluating and comparing the antioxidant and antibacterial activities of 10 marine algae extracts, we tried to find a marine alga extract that helps to extend the shelf life of salted pollack roe which also can be applied as a functional material with antibacterial activity. Among tested species, in DPPH free radical scavenging activity and total polyphenols content, Ecklonia cava and Gracilaria verrucosa extracts showed significant antioxidant activity and in paper disc diffusion, MIC and MBC tests, Ecklonia cava, Codium flagile and Gracilaria verrucosa extracts showed significant antibacterial activity. Based on the current results, marine algae extracts were suggested to help to extend the shelf life of salted pollack roe acting as functional materials with antioxidant and antibacterial activities.