• Journal of the Economic Geographical Society of Korea
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• v.24 no.1
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• pp.1-13
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• 2021

The POSCO Outsourcing Partners(POSOP) consisted of 59 companies plays an important role in creating jobs in Gwangyang City of Jeonnam Province, the representative steel city of Korea. However POSOP are suffering from a job shortage. The purpose of this study is to analyze the mismatch between job-seekers and job-openers in relation to employment in Gwangyang City. As a result of the job-mismatch analysis of nine factors, there was a clear mismatch in recognition of suppliers, access to corporate and employment information, employment information acquisition path, and employment preference factors. However, there was no mismatch in the factors of employment avoidance and difficulty in the job-seeking and recruitment process. As solutions to the mismatch, it proposes to redefine the role of POPOS, promote capacity building projects for labor-management co-prosperity and cooperation, and gradually promote related projects in connection with the master plan related a comprehensive plan for youth jobs.

• Current Optics and Photonics
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• v.5 no.2
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• pp.93-100
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• 2021

Three factors that degrade the accuracy of modal decomposition are extensively studied using simulated and measured beams. These include a beam size mismatch, beam center mismatch, and signal-to-noise ratio of the images. The beam size and beam center are scanned using simulated noisy beams, and the result of the modal decomposition is compared with that of real beams. Based on the suggested procedure, error functions of approximately 1-4 × 10-3 can be acquired for real beams. This study provides important information regarding the impact of the three factors on the practical modal decomposition and tolerances of a mismatch, helping estimate the achievable values of the error function in a real beam modal decomposition.

• Current Photovoltaic Research
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• v.7 no.4
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• pp.111-120
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• 2019

The output power of a crystalline silicon (c-Si) photovoltaic (PV) module is not directly the sum of the powers of its unit cells. There are several losses and gain mechanisms that reduce the total output power when solar cells are encapsulated into solar modules. Theses factors are getting high attention as the high cell efficiency achievement become more complex and expensive. More research works are involved to minimize the "cell-to-module" (CTM) loss. Our paper is aimed to focus on electrical losses due to interconnection and mismatch loss at PV modules. Research study shows that among all reasons of PV module failure 40.7% fails at interconnection. The mismatch loss in modern PV modules is very low (nearly 0.1%) but still lacks in the approach that determines all the contributing factors in mismatch loss. This review paper is related to study of interconnection loss technologies and key factors contributing to mismatch loss during module fabrication. Also, the improved interconnection technologies, understanding the approaches to mitigate the mismatch loss factors are precisely described here. This research study will give the approach of mitigating the loss and enable improvement in reliability of PV modules.

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.3
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• pp.347-353
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• 2017

We present a STT-MRAM read-circuit which mitigates the performance degradation caused by offsets from device mismatches. In the circuit, a single current source supplies read-current to both the data and the reference cells sequentially eliminating potential mismatches. Furthermore, an offset-free pre-amplification using a capacitor storing the mismatch information is employed to lessen the effect of the comparator offset. The proposed circuit was implemented using a 130-nm CMOS technology and Monte Carlo simulations of the circuit demonstrate its effectiveness in suppressing the effect of device mismatch.

• Journal of the Korean Solar Energy Society
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• v.39 no.6
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• pp.15-25
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• 2019

As the installation of photovoltaic systems increases, fire accidents of PV system grow every year. Most of PV system fires have been reported to be caused by electrical components. The majority of fire accidents occurred in combiner box, which is presumed to be short-circuit accidents due to dustproof and waterproof failures or heat deterioration of blocking diode. For this reason, the blocking diode installation became optional by revised PV combiner regulation. In this paper, according to the revised regulation, reverse current that generated by voltage mismatch was measured and analyzed in PV array without a blocking diode. The factors that cause voltage mismatch in array are assumed to be shaded PV module and short circuit failure of bypass diode. As the result of experiment, there is no reverse current to flow under shading condition in module, but reverse current flows on the failure of bypass diode in module. According to the module's I-V characteristic curve analysis, open voltage was slightly reduced due to operation of bypass diode in shading. However, it showed that open circuit voltage has decreased significantly in the failure of bypass diode. This indicates that the difference in open voltage reduction of voltage mismatch factor causes reverse current to flow.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.260-262
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• 2002

The determination of DNA hybridization can apply the molecular biology research. clinic diagnostics. bioengineering, environment monitoring, food science and other application area. So, The determination of hybridization is very important for the improvement of DNA detection system. In this study, we report the characterization of the DNA hybridization by the electricalchemical methods. The probe oligonucleotide was used to determine the amount of target oligonucleotide in solution using Methylen Blue(MB) as the electrochemical indicators. The cathodic peak currents($I_{peak}$) of MB were linearly related to the concentration of the target oligonucleotide sequence in the range $1[{\mu}M]{\sim}0.1[{\mu}M]$. The detection limit of this approach was 0.01[nM]. As a result, the match oligonucleotide(CR-1) was most stable state and the peak of redox current measured by DNA hybridization detection sensors by using electrochemical method seem to be similar to 1-mer terminal mismatch oligonucleotide(MR-3). The MR-2, MR-3, MR-22 and MR-33 have each mismatching sequence of central and terminal. With this set the role of point mutations was to be investigated. Terminal mismatch oligonucleotide (MR-3, 33) is shown more stable state than central mismatch oligonucleotide(MR-2, 22). And 1-mer mismatch oligonucleotide(MR-2 or 3) is shown more stable state than 2-mer mismatch oligonucleotide(MR-22 or 33).

• Journal of Electrical Engineering and Technology
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• v.12 no.4
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• pp.1593-1599
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• 2017

This paper presents a multi-channel light-emitting diode (LED) driver IC with a current-mode current regulator. The proposed current regulator replaces resistors for current sensing with a sequentially controlled single current sensor and a single regulation loop for sensing and regulating all LED channel currents. This minimizes the current mismatch among the LED channels and increases voltage headroom or, equivalently, power efficiency. The proposed LED driver IC was fabricated in a $0.35-{\mu}m$ BCD 60-V high voltage process, and the chip area is $1.06mm^2$. The measured maximum power efficiency is 93.4 % from a 12-V input, and the inter-channel current error is smaller than as low as ${\pm}1.3%$ in overall operating region.

• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.209-212
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• 2000

Charge pump based upon a phase locked loop(PLL) is described. This charge pump show that it is possible to overcome the issue of charge pump current mismatch by using a current subtraction circuit. Also, this charge pump can suppress reference spurs and disturbance of the VCO control voltage. HSPICE simulations are performed using 0.25$\mu\textrm{m}$ CMOS process.

• Journal of Power Electronics
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• v.10 no.5
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• pp.485-490
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• 2010

Sensorless control methods are generally used in motor control for home-appliances because of the material cost and manufactureing standard restrictions. The current model-based control algorithm is mainly used for PMSM sensorless control in the home-appliance industry. In this control method, the rotor position is estimated by using the d-axis and q-axis current errors between the real system and a motor model of the position estimator. As a result, the accuracy of the motor model parameters are critical in this control method. A mismatch of the PMSM parameters affects the speed and torque in low speed, steadystate responses. Rotor position errors are mainly caused by a mismatch of the stator resistance. In this paper, a stator resistance compensation algorithm is proposed to improve sensorless control performance. This algorithm is easy to implement and does not require a modification of the motor model or any special interruptions of the controller. The effectiveness of the proposed algorithm is verified through experimental results.

• Tribology and Lubricants
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• v.15 no.1
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• pp.8-16
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• 1999

The electrorheological (ER) behavior of suspensions in silicone oil of phosphoric ester cellulose powder (average particle size : 18$\pm$1 ${\mu}{\textrm}{m}$) was investigated on the elevated temperature up to 10$0^{\circ}C$. For development of anhydrous ER fluids using at wide temperature range, it should be researched to how the effect of temperature on the ER activities. As a first step, the anhydrous ER suspensions mixing with the phosphoric ester cellulose particles which were made from the phosphoric ester reaction of cellulose were measured. As increasing the temperature, not only the analysis of electrical properties such as dielectric constant current density and electrical conductivity but also the rheological properties of ER fluids were studied. From the experimental results, the temperature had a large influence to the ER properties of anhydrous ER fluids. The current density, conductivity and elecoorheological effect ($\tau$$_{A}$$\tau$$_{0}$) of phosphoric ester cellulose ER fluids were proportional to the temperature with power law. And the shear stress of them was closely related with the square of dielectric constant mismatch parameter ($\beta$$^2$) under constant shear rate and electric field.d.