• Title/Summary/Keyword: low-order control

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Algorithm for Switch Open Fault Detection of Asymmetric 6-phase PMSM Based on Stationary Reference Frame dq-axis Currents (비대칭 6상 영구자석 동기 전동기의 정지 좌표계 DQ축 전류를 이용한 스위치 개방 고장 검출 기법)

  • Lee, Won-Seok;Kim, Han-Eol;Hwang, Seon-Hwan;Lee, Ki-Chang;Park, Jong-Won
    • Journal of IKEEE
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    • v.26 no.2
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    • pp.265-270
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    • 2022
  • This paper proposes the detection algorithm for switch open fault of asymmetric 6-phase PMSM based on stationary reference frame dq-axis currents. In this paper, target motor has an asymmetric structure in which two upper three windings have an electrical phase difference of 30° and a neutral point is separated. As a result, dual 3-phase PWM inverters and the detection techniques due to open failures of switch are definitely required. In this paper, the dual dq-axis current control method is used for driving the asymmetric 6-phase PMSM and the open fault switch should be detected by using variable all pass filter and low pass filter in order to detect the current amplitude. The effectiveness and usefulness of the proposed method is verified by several experiments.

Development Trends of Liquid Methane Rocket Engine and Implications (액체로켓 메탄엔진 개발동향 및 시사점)

  • Lim, Byoungjik;Kim, Cheulwoong;Lee, Keum-Oh;Lee, Keejoo;Park, Jaesung;Ahn, Kyubok;Namkoung, Hyuck-Joon;Yoon, Youngbin
    • Journal of the Korean Society of Propulsion Engineers
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    • v.25 no.2
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    • pp.119-143
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    • 2021
  • Selecting liquid methane as fuel is a prevailing trend for recent rocket engine developments around the world, triggered by its affordability, reusability, storability for deep space exploration, and prospect for in-situ resource utilization. Given years of time required for acquiring a new rocket engine, a national-level R&D program to develop a methane engine is highly desirable at the earliest opportunity in order to catch up with this worldwide trend towards reusing launch vehicles for competitiveness and mission flexibility. In light of the monumental cost associated with development, fabrication, and testing of a booster stage engine, it is strategically a prudent choice to start with a low-thrust engine and build up space application cases.

Carbon monoxide releasing molecule-2 suppresses stretchactivated atrial natriuretic peptide secretion by activating largeconductance calcium-activated potassium channels

  • Li, Weijian;Lee, Sun Hwa;Kim, Suhn Hee
    • The Korean Journal of Physiology and Pharmacology
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    • v.26 no.2
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    • pp.125-133
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    • 2022
  • Carbon monoxide (CO) is a known gaseous bioactive substance found across a wide array of body systems. The administration of low concentrations of CO has been found to exert an anti-inflammatory, anti-apoptotic, anti-hypertensive, and vaso-dilatory effect. To date, however, it has remained unknown whether CO influences atrial natriuretic peptide (ANP) secretion. This study explores the effect of CO on ANP secretion and its associated signaling pathway using isolated beating rat atria. Atrial perfusate was collected for 10 min for use as a control, after which high atrial stretch was induced by increasing the height of the outflow catheter. Carbon monoxide releasing molecule-2 (CORM-2; 10, 50, 100 μM) and hemin (HO-1 inducer; 0.1, 1, 50 μM), but not CORM-3 (10, 50, 100 μM), decreased high stretch-induced ANP secretion. However, zinc porphyrin (HO-1 inhibitor) did not affect ANP secretion. The order of potency for the suppression of ANP secretion was found to be hemin > CORM-2 >> CORM-3. The suppression of ANP secretion by CORM-2 was attenuated by pretreatment with 5-hydroxydecanoic acid, paxilline, and 1H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one, but not by diltiazem, wortmannin, LY-294002, or NG-nitro-L-arginine methyl ester. Hypoxic conditions attenuated the suppressive effect of CORM-2 on ANP secretion. In sum, these results suggest that CORM-2 suppresses ANP secretion via mitochondrial KATP channels and large conductance Ca2+-activated K+ channels.

Microcode based Controller for Compact CNN Accelerators Aimed at Mobile Devices (모바일 디바이스를 위한 소형 CNN 가속기의 마이크로코드 기반 컨트롤러)

  • Na, Yong-Seok;Son, Hyun-Wook;Kim, Hyung-Won
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.26 no.3
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    • pp.355-366
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    • 2022
  • This paper proposes a microcode-based neural network accelerator controller for artificial intelligence accelerators that can be reconstructed using a programmable architecture and provide the advantages of low-power and ultra-small chip size. In order for the target accelerator to support various neural network models, the neural network model can be converted into microcode through microcode compiler and mounted on accelerator to control the operators of the accelerator such as datapath and memory access. While the proposed controller and accelerator can run various CNN models, in this paper, we tested them using the YOLOv2-Tiny CNN model. Using a system clock of 200 MHz, the Controller and accelerator achieved an inference time of 137.9 ms/image for VOC 2012 dataset to detect object, 99.5ms/image for mask detection dataset to detect wearing mask. When implementing an accelerator equipped with the proposed controller as a silicon chip, the gate count is 618,388, which corresponds to 65.5% reduction in chip area compared with an accelerator employing a CPU-based controller (RISC-V).

On the Design of Power Supply System for Freight Train Reefer Container Based on Simulation

  • Kim, Joouk;Hwang, Sunwoo;Lee, Jae-Bum;Hwang, Jaemin;Chae, Uri
    • International Journal of Internet, Broadcasting and Communication
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    • v.14 no.3
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    • pp.249-257
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    • 2022
  • In recent years, if we order food by easily accessing the online market with our smartphone, we can receive the product in a fresh state at dawn the next day. Cold chain is an industry that can create high added value because it has both the characteristics of general logistics and sensitivity to temperature. Based on the electrical specifications derived from the reefer container capacity requirement investigation, we proved that power supply to up to 33 reefer containers can be made by using three additional auxiliary power supplies which are applied for freight trains in Korea. In this paper, we conducted a research on a design of power supply system for freight train reefer container based on simulation as a basic research necessary for low-temperature distribution and cold chain construction based on the reefer container railroad. Consequently, the simulation was conducted using the three-phase inverter diagram in PSIM and the SVPWM (3-harmonic injection method) control technique, and it was verified that the required power voltage was satisfied with 622Vdc, which is lower than the input voltage of general SPWM of 718Vdc. The details of this paper could be used as a foundational study for constructing cold chains based on a reefer container dedicated to freight trains in the future.

Agro-morphological Characterization of Korean, Chinese, and Japanese Adzuki Bean (Vigna angularis (Willd.) Ohwi & Ohashi) Genotypes

  • Kebede Taye Desta;Yu-Mi Choi;Jung-Yoon Yi;Sukyeung Lee;Myoung-Jae Shin;Xiao-Han Wang;Hyemyeong Yoon
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.68 no.1
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    • pp.8-19
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    • 2023
  • Adzuki beans have gained popularity in recent years due to their health benefits. Breeding of Adzuki beans is less favorable than with other legumes due to low genetic diversity. This study aimed to evaluate the genetic diversity of 252 adzuki bean germplasms from China, Japan, and Korea using 18 agro-morphological parameters and comparing their performance to three prominent Korean cultivars: Geomguseul, Arari, and Chungjupat. Leaf shape, pod color, and seed coat color were among the qualitative traits that showed wide variations. The quantitative variables also showed wide variations among adzuki bean germplasms. Although there was no significant difference (p < 0.05), the average rate of germination declined in the order of Korean (91.44%) > Chinese (91.31%) > Japanese (87.47%) adzuki beans. Chinese adzuki beans needed fewer days to flower (DF, 58.22 days) and days to mature (DM, 107.13 days), which varied significantly compared to the Korean and Japanese adzuki beans (p < 0.05). The average number of pods per plant (PPP) and one-hundred seeds weight (HSW) were higher in Japanese adzuki beans compared to the Korean and Chinese adzuki beans although the variation of each was not significant. Almost 29.76% of the accessions had early-blooming flowers, 3.97% were premature, 21.43% produced more PPP, and 3.97% yielded more SPP compared to control cultivars. Results of hierarchical cluster and principal component analyses revealed three clusters with significant variation in all quantitative variables except for RG (p < 0.05). The key factors in multivariate analyses were DF, DM, and HSW. Our study investigated the genetic diversity of adzuki bean accessions and identified ten early maturing and ten high PPP-yielding accessions. Our findings would help farmers and breeders to select the top-performing accessions that can provide them with various options.

DEVELOPMENT OF ERP INTEGRATION SYSTEM FOR SPORTS INDUSTRY IN TAIWAN

  • Yan-Chyuan Shiau;Yu-Min Hsu;Shu-Jen Sung;Chih-Kun Chu;Hsiang-Lun Cheng;Tsung-Pin Tsai
    • International conference on construction engineering and project management
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    • 2005.10a
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    • pp.1028-1035
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    • 2005
  • Traditional Industries were planning the major role for Taiwan's economy. However, we need to face the competition from developing countries. Moving manufacturing department to other low salary countries, such as China, can only temporarily release some limited pressure. The final and complete solutions are to equip on R&D, refine techniques, improve management capabilities, upgrade business, and reform physique. Currently there are some ERP systems on the market; however, they are designed for common purpose and difficult to introduce into industry. The expensive price is another factor to make them be popular. In this research we will Object Oriented, Visual Modeling, ER Model and Windows Environment to develop an Integrated Management System for Sports Requisites Industries (IMSSRI). We will integrate all information from all departments such as development, business, material administration, manufacture, shipping, and financial. When development people construct the all modules, components, cutting molds, materials and accessories, IMSSRI will calculate all needed materials and cost for each product. This cost will be used for quotation to report to our customers. When customers confirm the order, system will transfer all necessary materials into Material Administration System. IMSSRI can generate manufacturing forms and material raw lists for manufacture department. All related information such as stocking, returning goods, material requesting, and material returning can be integrated so we can control all details of the whole enterprise. Through the help of this system, we hope we can save man-power, reduce human mistakes, raise management capabilities for tradition manufacturing industries and create another possibility of eternal operating for Taiwan's Industries.

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Development of exothermic system based on internet of things for preventing damages in winter season and evaluation of applicability to railway vehicles

  • Kim, Heonyoung;Kang, Donghoon;Joo, Chulmin
    • Smart Structures and Systems
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    • v.29 no.5
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    • pp.653-660
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    • 2022
  • Gravel scattering that is generated during operation of high-speed railway vehicle is cause to damage of vehicle such as windows, axle protector and so on. Especially, those are frequently occurred in winter season when snow ice is generated easily. Above all, damage of vehicle windows has not only caused maintenance cost but also increased psychological anxiety of passengers. Various methods such as heating system using copper wire, heating jacket and heating air are applied to remove snow ice generated on the under-body of vehicle. However, the methods require much run-time and man power which can be low effectiveness of work. Therefore, this paper shows that large-area heating system was developed based on heating coat in order to fundamentally prevent snow ice damage on high-speed railway vehicle in the winter season. This system gives users high convenience because that can remotely control the heating system using IoT-based wireless communication. For evaluating the applicability to railroad sites, a field test on an actual high-speed railroad operation was conducted by applying these techniques to the brake cylinder of a high-speed railroad vehicle. From the results, it evaluated how input voltage and electric power per unit area of the heating specimen influences exothermic performance to draw the permit power condition for icing. In the future, if the system developed in the study is applied at the railroad site, it may be used as a technique for preventing all types of damages occurring due to snow ice in winter.

Reduced use of nitrogen fertilizer through retarded hydrolysis of urea by pyroligneous acid for Chinese cabbage cultivation (배추 재배 시 목초액에 의한 요소 가수분해 지연을 통한 질소비료 절감 효과)

  • Lee, Joo-Kyung;Park, Hyun Jun;Park, Jin Hee
    • Journal of Applied Biological Chemistry
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    • v.65 no.1
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    • pp.1-6
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    • 2022
  • Urea is one of the most common nitrogen fertilizer, but nitrogen use efficiency by crop is low because of rapid hydrolysis of urea and loss of nitrogen in environments. Therefore, it is important to control the nitrogen release from nitrogen fertilizers. In this study, pyroligneous acid (PA) was used as a mean to inhibit urease in soil and prevent excessive nitrogen release from urea. Active ingredient in PA (AI) inhibited ammonification of urea in soil by reducing extracted ammonium nitrogen at 79.7% compared to the soil without PA. In order to evaluate the effect of PA on fertilization efficiency of urea, Chinese cabbage (Brassica campestris var. Pekinensis) was cultivated in soil treated with urea and PA both in pot and field. For PA treatment, half amount of urea was used compared to the amount of urea conventionally applied to Chinese cabbage. The PA treatment with half amount of urea resulted in similar Chinese cabbage biomass to the conventional urea application. Nitrogen concentration in Chinese cabbage was less in PA treatment indicating that Chinse cabbage effectively used nitrogen. Consequently, fertilization of urea with PA will reduce amount of fertilizer and frequency of application.

Study on Enhancing National Defense Security based on RFID and Internet of Things Technology (RFID와 사물인터넷을 활용한 국방 보안 강화에 대한 연구)

  • Oh, Se-Ra;Kim, Young-Gab
    • Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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    • v.7 no.2
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    • pp.175-188
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    • 2017
  • Radio-frequency identification (RFID) is being used in various fields as a technology for identifying objects (people, things etc.) using radio frequencies. In the past, there was an attempt to apply RFID into national defense, but failed to spread RFID in the defense field because of some limitations of RFID in a specific situation (e.g., low recognition rate). Therefore, in this paper, we propose how to overcome the limitation of RFID by adopting the Internet of Things (IoT) technology which is considered as an important technology of the future. Furthermore, we propose four scenarios (i.e., healcare band and RFID, identification and anormal state detection, access control, and confidential document management) that can be used for enhancing national defense security. In addition, we analyze the basic characteristics and security requirements of RFID and IoT in order to effectively apply each technology and improve security level.