22 results on '"Hyun-Jung Lee"'
Search Results
2. Low temperature atomic layer deposition of Ru thin films using a new carbonyl-based Ru precursor and non-oxidizing reactants; Applications to the seed layer for Cu metallization
- Author
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Ryosuke Harada, Hyun-Jung Lee, Soo-Hyun Kim, Tae Eun Hong, and Shunichi Nabeya
- Subjects
Secondary ion mass spectrometry ,Atomic layer deposition ,Materials science ,chemistry ,Annealing (metallurgy) ,Impurity ,Torr ,Analytical chemistry ,chemistry.chemical_element ,Thin film ,Oxygen ,Chamber pressure - Abstract
We report ALD-Ru thin films using a new carbonyl-based Ru precursor and compare the results with various nonoxidizing reactants such as H 2 , NH 3 , CO molecule and NH 3 , N 2 , H 2 , N 2 +H 2 mixture plasma. In addition, we also investigatd ALD-Ru process with post annealing and in-situ periodic plasma treatment to improve ALD-Ru film quality. The Ru film was deposited at the deposition temperature ranging from 100 to 150 C and at the chamber pressure from 1 to 50 Torr. In the case of using N 2 and H 2 mixture plasma as a reactant, it was possible to deposit Ru film even at a substrate temperature of 100C and the film resistivity of ∼ 70 µΩ·cm was deposited after annealing and in-situ plasma treatment. It was shown that ALD-Ru film with the resistivity of ∼ 25 µΩ·cm could be prepapred using H 2 molecules at 150C with increasing chamber pressure up to 30 Torr. The step coverage of ALD-Ru films deposited using H 2 molecuels and at the chamber pressure of 30 Torr was excellent, around 100 % at dual trench structure with aspect ratio of ∼ 6.3. It should be noted that ALD-Ru films deposited using H 2 molecules contained no oxygen and carbon impurities while Ru films using deposited diluted O 2 has oxygen and carbon impurities by secondary ion mass spectrometry depth profile. And electro-plating of Cu is successfully possible on ALD-Ru deposited using H 2 molecules at 30 Torr.
- Published
- 2017
3. Situation reasoning framework for the Internet of Things environments using deep learning results
- Author
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Haeran Jin, Seyoung Park, Mye M. Sohn, and Hyun Jung Lee
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Thesaurus (information retrieval) ,Situation awareness ,business.industry ,Computer science ,Deep learning ,Machine learning ,computer.software_genre ,Hierarchical clustering ,Deep neural networks ,Case-based reasoning ,Artificial intelligence ,Data mining ,Internet of Things ,business ,computer ,Case base - Abstract
A goal of this paper is to suggest a framework to infer the situation using IOT sensor data. To do so, the framework adopts contexts which were derived from the learning results of multiple deep neural networks for IOT sensor data and carries out hierarchical clustering of contexts in terms of the spatio-temporality. With the learned dendrogram, the most appropriate situation is inferred from case-based reasoning depending on the similar time and location. The result of reasoning is stored in a case memory and this can contribute to learning of a case base. The primary contribution of this paper is the situation reasoning under consideration for spatio-temporality that is a characteristic of IOT sensor data. Also, we performed experiments to show the superiority of our framework. The experimental results are not bad for a first attempt. In further research, if the algorithms are improved, we can expect better results.
- Published
- 2016
4. Health Service Knowledge Management to Support Medical Group Decision Making
- Author
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Mye M. Sohn and Hyun Jung Lee
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Medical algorithm ,Knowledge management ,Computer science ,business.industry ,Medical record ,0206 medical engineering ,Context (language use) ,02 engineering and technology ,Ontology (information science) ,020601 biomedical engineering ,Group decision-making ,Health services ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Case-based reasoning ,Decision-making ,business - Abstract
In this study, we are proposing a medical group decision making using Health Service Knowledge Management (HSKM) with interactively extracted context from patients and doctors by sharing of health information. Especially, in the area of tele-healthcare, it is necessary to share distributed medical information to make medical decisions because it is not easy to make a decision without any face-to-face contact between patients and doctors. Occasionally, medical teams often need to share medical information with far-off clinicians to care patients much more. For such a reason, it is sufficient to develop HSKM for healthcare systems. The developed HSKM is applied to make a medical decision for patients, which is based on Health Service Ontology and Case-based reasoning (CBR). Health Service Ontology is based on medical information like symptoms, diseases, departments and doctors knowledge. Medical records are stored as cases in knowledge-base. The cases are applied to find appropriate medical cases in the medical group decision making using CBR. To extract a medical decision, patients and doctors' interactive contexts are considered during the making a medical decision. The contexts are operated as constraints to reach the medical goal using Constraints Satisfaction Problem (CSP). We used an example to discuss the necessity of the proposed HSKM and we expect the implementation and verification of the superiority of the system in further research.
- Published
- 2016
5. The method of roll maintain for spherical robot of torque driven type from the external impact
- Author
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Hyun Jung Lee, Gye-Do Park, Jang-Myung Lee, and Kyoung Hwan Kim
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Engineering ,Angular acceleration ,business.industry ,Gyroscope ,Mobile robot ,Moment of inertia ,law.invention ,Computer Science::Robotics ,Acceleration ,Control theory ,law ,Torque ,business ,Spherical robot ,Roll moment - Abstract
This paper propose a new balance control method of spherical robot. When motors generate turning force, Spherical robot can maintain the balance for roll using the moment of inertia and angular acceleration. This method which is fixed to the center axis by bearing has zero angular acceleration, so spherical robot maintains the balance from disturbance and external impact. For the measurement of roll slope, this system used the gyro and acceleration sensor and used the kalman filter because of exact measurement of gyro and acceleration sensor which have a noise.
- Published
- 2011
6. Protection Profile of Personal Information Security System: Designing a Secure Personal Information Security System
- Author
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Dongho Won, Kwangwoo Lee, and Hyun Jung Lee
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Information privacy ,Privacy by Design ,Privacy software ,Computer science ,business.industry ,Privacy policy ,Internet privacy ,ComputingMilieux_LEGALASPECTSOFCOMPUTING ,Information privacy law ,Computer security ,computer.software_genre ,Data Protection Act 1998 ,Privacy law ,business ,Personally identifiable information ,computer - Abstract
As cyber-crimes using personal information such as ID theft are increasing, there is a need for appropriate technology or law to protect privacy. To this end, the Korean Government established the Privacy Act on March 29th 2011. The Privacy Act prescribes a specification for dealing with privacy with the intention to protect personal information from being collected, leaked, misused, or abused so that it can improve rights and interests of the nation and eventually realize the dignity and value of man. The United States, Japan, Canada, and several countries of the EU have their own privacy law being established or revised. Although there must be differences depending on the circumstances of each country, the ultimate goal of the privacy law should be the same. Consequently, there might be the same or similar technical protection required by all these countries. Between the increasing interest in protecting personal information and the establishment of the Privacy Act, many industries are having relevant products released one after another. Customers without knowledge of the law and the product types cannot decide what they need. This paper intends to derive necessary security functions of a personal information security system based on the Common Criteria and analyze the limit of the products in order to make guidelines for privacy and information protection system.
- Published
- 2011
7. Personalized Information Recommendataion Using Hybrid CBR and CSP in a Ubiquitous Computing Environment
- Author
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Hyun Jung Lee, Hyunwoo Kim, and Mye M. Sohn
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World Wide Web ,Context model ,Ubiquitous computing ,End user ,Human–computer interaction ,Tacit knowledge ,Computer science ,Context (language use) ,Ontology (information science) ,Recommender system ,Adaptation (computer science) - Abstract
Dynamic adaptation is to create proper information from the context of the end user exposed to a ubiquitous computing environment. Thereby, we propose a Context Ontology-based personalized recommendation in the ubiquitous computing Environment (CORALE) framework to process dynamic adaptation considering social context as a kind of tacit knowledge. The CORALE uses two types of reasoning for the dynamic adaptation, (i) we create a case including an end user's context and decision-making result and reuse the case to recommend a newly requested context, (ii) we adopt constraint satisfaction problem solving algorithm when additional adaptation is needed according to the change in the current context or end user' preference. To prove the necessity of the CORALE framework, we illustrate motivating scenarios.
- Published
- 2011
8. Beacon scheduling for efficient localization of a mobile robot
- Author
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Seoyoung Hwang, Yo-Seop Hwang, Jang-Myung Lee, Hyun Jung Lee, and Jaehyun Park
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Engineering ,business.industry ,Real-time computing ,Economic shortage ,Mobile robot ,Workspace ,Mobile robot navigation ,Beacon ,Scheduling (computing) ,ComputerSystemsOrganization_SPECIAL-PURPOSEANDAPPLICATION-BASEDSYSTEMS ,Ultrasonic sensor ,Motion planning ,business ,Simulation - Abstract
This paper proposes the localization scheme using ultrasonic beacons in a multi-block workspace. Indoor localization schemes using ultrasonic sensors have been widely studied due to their cheap price and high accuracy. However, ultrasonic sensors are susceptible to environmental noises from their propagation characteristics. On account of their decay phenomena when they are transmitted over a long distance, ultrasonic sensors are not suitable for application in large indoor environments. To overcome these shortages of ultrasonic sensors while emphasizing their advantages, a multi-block approach has been proposed by dividing the indoor space into several blocks with multiple beacons in each block. This approach, however, is hard to divide into several blocks when beacons are not installed in a certain pattern, and in case of having newly installed beacons, all blocks placement is reconstructed. Therefore, this paper proposes a real time localization scheme to estimate the position of mobile robot without effecting beacons placement. Beacon scheduling algorithm has been developed to select the optimal beacons according to robot position and beacon arrangement for the mobile robot navigation. The performance of the proposed localization system is verified through simulations and real experiments.
- Published
- 2011
9. Novel stress-memorization-technology (SMT) for high electron mobility enhancement of gate last high-k/metal gate devices
- Author
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Kang-ill Seo, Jongwan Choi, Sang-pil Sim, Yangsoo Sohn, Seung-Hun Lee, Kwan-Heum Lee, Si-Young Choi, Chulgi Song, Kyungseok Oh, Junghyun Park, Choongryul Ryu, Tae-Ouk Kwon, Chilhee Chung, Hyun-Jung Lee, Sang Bom Kang, Hee-Kyung Jeon, Wookje Kim, Seok-Hoon Kim, Kwan-Yong Lim, Uihui Kwon, Hong-Sik Yoon, Chung Geun Koh, Jinyeong Cho, and Eunha Lee
- Subjects
Stress (mechanics) ,Materials science ,business.industry ,Logic gate ,Electrical engineering ,Optoelectronics ,D region ,Dislocation ,business ,Metal gate ,High electron ,High-κ dielectric ,Communication channel - Abstract
High-k/metal gate (HKMG) compatible high performance Source/Drain (S/D) stress-memorization-technology (SMT) is presented. Channel stress generated by SMT can be simulated by using mask-edge dislocation model, which is consistent with the measured actual channel stress. Extremely deep pre-amorphization-implant (PAI) for SMT creates multiple mask-edge dislocations under S/D region, which enhances short-channel mobility by 40∼60%. Finally, more than 10% short channel drive current gain is achieved with additional S/D extension optimization.
- Published
- 2010
10. Trajectory planning of autonomous robot using advanced fuzzy controller
- Author
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Hyun Jung Lee, Jang-Myung Lee, Sungha Kim, and Chi-Sung Park
- Subjects
Robot kinematics ,Computer science ,Obstacle ,Obstacle avoidance ,Trajectory ,Robot ,Mobile robot ,Control engineering ,Motion planning ,Autonomous robot - Abstract
To move a obstacle from a certain position to the predefined destination, robot needs various kinds of elements, like control algorithm, hardware, etc. General human can selects the distance between him and destination by numerical supervised learning, and establish the moving plan to the destination, generally called ‘Trajectory planning.’ He(or she) can make a trajectory planning against the obstacles which is placed on the path to the destination. The kinds of obstacle can be active obstacle, which is moving on the trajectory, or passive obstacle, which is stationary one. For the kinds of stationary obstacle is height difference between road and sidewalk, stairs, a ramp. And the active obstacles include a human, a vehicle that shows active motion. To make a trajectory planning for the stationary obstacle, autonomous mobile robot can be assume that it is placed at the center of the map, and from the distance information between autonomous mobile robot and obstacles using the advanced fuzzy controller, mobile robot can make a trajectory planning. But in case of active moving obstacle, there are many components and information is needed to process because its moving trace should be considered in real time. As mentioned above, for the proposed algorithm, various kinds of things should be considered to move to the destination. Obviously, autonomous driving of the mobile robot can provide conveniences to the human-being with the various kinds of aspects. In this paper, obstacle avoidance algorithm for the trajectory planning using advanced fuzzy controller is described in detail, and demonstrated proposed algorithm through the real experiment.
- Published
- 2010
11. Rapid immunosensing based on accumulation of microparticles by negative dielectrophoresis
- Author
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Yusuke Yoshida, Fumio Mizutani, Tomoyuki Yasukawa, Hyun Jung Lee, Tomokazu Matsue, Hitoshi Shiku, and Javier Ramón-Azcón
- Subjects
Analyte ,Electrophoresis ,Chromatography ,Materials science ,medicine.diagnostic_test ,Immunoassay ,Microfluidics ,medicine ,Substrate (chemistry) ,Dielectrophoresis ,Biosensor ,Fluorescence - Abstract
In the work, microfluidic device consisting of an interdigitated microarray (IDA) electrode was developed for a rapid, and separation-free immuno-sensors based on a manipulation technique of microparticles by dielectrophoresis (DEP). A poly-dimethylsiloxane (PDMS) substrate with microfluidic channel was placed on the IDA plate to allow to fabricating the device. On applying AC voltage to the IDA in a negative DEP (n-DEP) frequency region, goat anti-mouse immunoglobulin (anti-mouse IgG)-immobilized microparticles moved to the surface of PDMS substrate placed above the IDA by n-DEP force to accumulate at the designated areas of the PDMS surface, where anti-mouse IgG was precoated. When the fluorescence microparticles bearing anti-mouse IgG were suspended in an analyte (mouse IgG) solution, the microparticles trapped the analyte to form microparticle-conjugates. The conjugates were accumulated and captured at the designated areas of the PDMS surface via antibody-antigen-antibody (sandwich) reaction. The captured microparticles were detected selectively by fluorescence measurements at the focused, designated areas regardless of the presence of uncaptured microparticles in the suspended solution. Thus, the separation and washing-out steps, usually required for conventional immunoassay, are eliminated in the presented procedure. Since the formation of the sandwich structures was accelerated significantly by n-DEP, as short as 30 sec was enough to detect the immunoreaction at the surface. The fluorescence intensity of the captured microparticles at the designated area increased with the analyte in the range, 0.01 ~ 10 ng/mL. The present procedure realizes a rapid, sensitive and separation-free immunoassay in a simple device.
- Published
- 2009
12. Electrical impedance tomography reconstruction algorithm using extended Kalman filter
- Author
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Hyun Jung Lee, J.W. Park, H.-C. Kim, and Kyung Youn Kim
- Subjects
Moving horizon estimation ,Extended Kalman filter ,Computer science ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Fast Kalman filter ,Reconstruction algorithm ,Kalman filter ,Iterative reconstruction ,Electrical impedance tomography ,Algorithm ,Invariant extended Kalman filter - Abstract
In electrical impedance tomography (EIT), the internal resistivity distribution of the unknown object is estimated using the boundary voltage data induced by different current patterns using various reconstruction algorithms. This paper presents a reconstruction algorithm based modified extended Kalman filter technique that is able to track fast change in the impedance distribution. The computer simulation for the 32 channels synthetic data shows that the reconstruction performance of the proposed scheme is improved compared to that of the conventional Kalman filter algorithm at the expense of slightly increased computational burden.
- Published
- 2002
13. Estimation of errors in inertial navigation systems with GPS measurements
- Author
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Sinpyo Hong, Sung-Ha Kwon, Soon Bong Choi, Fumio Harashima, Hyun Jung Lee, and Man Hyung Lee
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GPS disciplined oscillator ,Control theory ,Estimation theory ,business.industry ,Computer science ,Assisted GPS ,GPS/INS ,Global Positioning System ,Observability ,Antenna (radio) ,business ,Inertial navigation system ,Computer Science::Information Theory - Abstract
In this paper, observability properties of a multiantenna GPS measurement system for the estimation of errors in INS are presented. It is shown that time-invariant INS error models are observable with measurements from at least three GPS antennas on the vehicle. There is at least one unobservable mode with two antennas. There are three unobservable modes with one antenna. It is also shown that time-varying INS error models are instantaneously observable with measurements from three GPS antennas. A numerical simulation results are given to verify the effectiveness of the multiantenna measurement system on the INS error estimation. In the simulation, a GPS measurement system is considered in which a trade-off between computational load and accuracy of estimation is achieved.
- Published
- 2002
14. Personalized Information Recommendataion Using Hybrid CBR and CSP in a Ubiquitous Computing Environment.
- Author
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Mye Sohn, Hyunwoo Kim, and Hyun Jung Lee
- Published
- 2011
- Full Text
- View/download PDF
15. Rapid immunosensing based on accumulation of microparticles by negative dielectrophoresis.
- Author
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Yasukawa, T., Hyun Jung Lee, Ramon-Azcon, J., Yoshida, Y., Shiku, H., Matsue, T., and Mizutani, F.
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- 2009
- Full Text
- View/download PDF
16. The compact multi-band internal chip antenna.
- Author
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Young-Hee Cho, Jae-Kwon Park, Jung-Min Kim, Sang-Hyeok Cho, Hyun-Jung Lee, Kyoung-Ho Lee, In-Young Lee, and Jong-Soo Kim
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- 2007
- Full Text
- View/download PDF
17. Development of Numerical Model of KSTAR PF Conductor and Magnet for the Analyses of AC Loss on the Results of KSTAR PF Magnet Test Run.
- Author
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Dong Keun Oh, Hyun Jung Lee, Sang-Hee Hahn, Yeong-Kook Oh, and Keeman Kim
- Subjects
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MAGNETS , *NUMERICAL analysis , *MATHEMATICAL models , *FLUCTUATIONS of superconducting magnets , *ALTERNATING currents - Abstract
To analyse the experimental results of PF magnet during the commissioning test of KSTAR, a numerical model of the PF1 magnet and its CICC was developed for the evaluation of Joule heat from the AC loss due to the time varying field profile along the conductor during ramping-up or down taking into account the ferromagnetic effect of Incoloy 908 jacket. The calculation routines was carefully updated to make a proper estimation of the AC loss and applied to the estimation of AC loss parameters of the CICC of the KSTAR PF magnet. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
18. KSTAR Magnetic Field Measurement During the Commissioning and Remanent Field Evaluation.
- Author
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Yonekawa, Hirofumi, Kim, Y. O., Hyun Jung Lee, Yoon, S. W., Hahn, S. H., Lee, K. S., Lee, D. K., Soo Hwan Park, Yong Chu, Bang, E. N., Park, K. R., Oh, Y. K., Bak, J. S., and Leuer, J. A.
- Subjects
MAGNETIC fields ,SUPERCONDUCTING magnets ,PALEOMAGNETISM ,TOROIDAL magnetic circuits ,FERROMAGNETISM ,HYSTERESIS - Abstract
An in-situ measurement of the magnetic field generated by the assembled superconducting magnet coils was held by using precision Hall sensors during the commissioning of the Korea Superconducting Tokamak Advanced Research (KSTAR) device. This was done in order to investigate the magnetic influence of Incoloy 908, which is the jacket material for the cable-in-conduit conductors (CICCs) of the Nb3 Sn coils. After the PF coils were discharged from 1 kA the vertical remanent field at the plasma center was more than 10 G, while the TF coils were not energized. The vertical magnetic field generated by the PF coils had a discrepancy of up to 50 G between measurement and the calculation assuming no magnetic influence of Incoloy 908. Thus, non-negligible ferromagnetism was identified and attributed to Incoloy 908. In contrast, most of the hysteresis observed in the magnetic measurements was eliminated when the Incoloy 908 of the TF windings was saturated by the TF coil charging. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
19. Hydraulics of KSTAR Central Solenoid Model Coil 2nd Campaign.
- Author
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Soo Hwan Park, Han, W. S., Moon, K. M., Park, W. W., Kim, J. S., Yonekawa, Hirofumi, Yong Chu, Hyun Jung Lee, Cho, K. W., Park, K. R., Kim, W. C., Yaung-Soo Kim, Oh, Y. K., and Bak, J. S.
- Subjects
SUPERCONDUCTING magnets ,SOLENOIDS ,HYDRAULICS ,HELIUM ,TOROIDAL magnetic circuits ,LOW temperature engineering ,FRICTION - Abstract
KSTAR (Korea Superconducting Tokamak Advanced Research) superconducting magnet consists of a CICC (Cable-In-Conduit Conductor) and is cooled down less than 5 K using supercritical helium. The length of CICC is 610 m for TF coil and maximum about 2,500 m for PF coil respectively, especially the cooling channel is about maximum 300 m in PF coil because of continuous winding scheme. There are many cooling channels in KSTAR coils especially 84 channels in TF magnet system and 100 channels in PF magnet system. Flow imbalance affects cool down of magnet and leads to a difficulty of flow control. The pressure drop between CICC terminals has a close relationship with CICC hydraulic characteristic, helium refrigerator's performance and efficiency. The friction factor which is a representative parameter can be obtained under cryogenic operation condition. We attempt to find out the friction factor of KSTAR CS and PF CICC according to the test result of KSTAR CSMC (Central Solenoid Model Coil) 2nd campaign and compare the results with previous tests. The hydraulic characteristics of KSTAR superconducting magnet system like mass flow distribution, friction factor in conductor, pressure drop and etc during CSMC test and initial commissioning of KSTAR are presented. We can confirm the KSTAR CICC's unique hydraulic behavior in states of cool down and current charging period. Also, we expect that measured data will help to operate KSTAR and be a reference for thermo-hydraulic simulation. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
20. Qualification Test Results of the KSTAR Superconducting Coils From the Construction to the Commissioning Steps.
- Author
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Park, K. R., Yong Chu, Yonekawa, Hirofumi, Baang, E. N., Kim, Y. O., Hyun Jung Lee, Park, Y. M., Lee, Y. J., Chang, H. S., Lee, D. K., Choi, J. H., Park, S. H., Hahn, S. H., Kim, K. H., Hwang, I. S., Park, M. K., Cho, K. W., Kim, Y. S., Oh, Y. K., and Bak, J. S.
- Subjects
SUPERCONDUCTORS ,TOROIDAL magnetic circuits ,MAGNETIC fields ,STRAINS & stresses (Mechanics) ,LOW temperatures - Abstract
To achieve the first plasma of the Korea superconducting tokamak advanced research (KSTAR), the KSTAR superconducting coils were tested in advance. As they should operate in excessively low temperature of 4.5 K and high magnetic field environment of 7.5 T, it is crucial to monitor the cryogenic and the structural behaviors of KSTAR device during the commissioning period including a cool-down. The temperatures of the KSTAR toroidal field (TF) coil and the poloidal field (PF) coils were measured during the entire operating period. The mechanical stresses on the TF and PF structures were continuously monitored to check if they go beyond the limiting value calculated through the simulation. The alignment of the KSTAR device was checked by using displacement sensors. The TF coils were successfully supplied with 15 kA DC current for 8 hours, and the maximum 5 kA/s current variation of the PF coils were tested. For the main experiment, the interlock test of the quench detection system for the KSTAR coils was carried out at reduced currents of 1 kA. From these results the quench protection circuit, and the current-flow of the KSTAR superconducting coils proved to be well performed for the first plasma operation. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
21. Quench Detection Based on Voltage Measurement for the KSTAR Superconducting Coils.
- Author
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Yong Chu, Yonekawa, Hirofumi, Kim, Y. O., Park, K. R., Hyun Jung Lee, Park, M. K., Park, Y. M., Lee, S. J., Ha, T. H., Oh, Y. K., and Bak, J. S.
- Subjects
ELECTRIC potential ,SUPERCONDUCTORS ,TOKAMAKS ,TOROIDAL magnetic circuits ,MAGNETIZATION - Abstract
To protect the KSTAR (Korea Superconducting Tokamak Advanced Research) superconducting coils against a quench, the quench detection system based on voltage measurement was fabricated. It used a detect/dump scheme which detects the presence of non-recovering normal zones and activates a dump circuit that transfers most of the stored energy into a dump resistor. Even though it is desirable to discharge the coil energy as fast as possible after quench detection, a time delay between the quench detection and the complete dump circuit actuation will be necessary in order that the quench voltage is to be distinguished from various noises. The quench threshold voltage and the delay time should be set before operation for quench voltage detection so that the maximum hot-spot temperature could be limited to 150 K. This paper describes the hardware techniques to prevent the malfunction of the quench detection due to voltage noises arising from the KSTAR operating scenarios. During the first operation of the KSTAR machine, the inductive voltages and other voltage noises were measured and effectively compensated below voltage thresholds. A quench did not occur and the quench detection system was well operated without any false activation. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
22. Comparison of Electrical Properties and Bias Stability of Double-Gate a-HIZO TFTs According to TFT Structure.
- Author
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Young Wook Lee, Sun-Jae Kim, Soo-Yeon Lee, Woo-Geun Lee, Kap-Soo Yoon, Hyun-Jung Lee, Ji-Soo Oh, Jae-Woo Park, and Min-Koo Han
- Subjects
ELECTRIC properties of solids ,HAFNIUM ,ZINC oxide films ,STRAINS & stresses (Mechanics) ,ELECTRODES ,ELECTRIC charge - Abstract
We fabricated two types of double-gate amorphous hafnium-indium-zinc oxide thin-film transistors: a back-channel etch (BCE) type and an etch stopper (ES) type. The normalized on-current and field-effect mobility of the BCE type are larger than those of the ES type. Furthermore, when applied with a positive bias stress, stability trends compared for each single-gate device are different according to structures. We suggest that the reason for the different electrical properties and bias stability originates from the ES structure in which some regions under the source/drain electrodes block the top-gate field; thus, there is no carrier accumulation or charge trapping into the dielectric layer. [ABSTRACT FROM PUBLISHER]
- Published
- 2012
- Full Text
- View/download PDF
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