• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.2
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• pp.216-223
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• 2018

Since solar cells have non-linear voltage-current output characteristics, Photovoltaic systems require the Maximum Power Point Tracking(MPPT) function. For this reason, a large number of MPPT techniques have been studied. However, the conventional MPPT techniques may fail to track the maximum power point when partial shading occurs in the solar cell array due to its characteristics. Therefore, it is necessary to research the MPPT technique that can follow the maximum power point in the partial shadow condition. In this paper, the characteristics of solar cell arrays in partial shadowing are analyzed and the MPPT technique which can follow the maximum power point in partial shadow condition has been proposed. To validate the proposed MPPT method, simulation and experimentation results are provided.

• The Journal of Information Systems
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• v.32 no.2
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• pp.25-43
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• 2023

Purpose In online delivery platforms, platform workers are required to perform both platform labor, which is compensated with immediate wages, and shadow work which is a kind of unpaid job to support the platform labor. Thus, the objective of this study is to empirically examine how platform workers' platform labor and shadow work affect their job burnout and their turnover intention in the online delivery platform context. Design/methodology/approach This study developed a research model by employing platform labor and shadow work to influence job burnout and turnover intention. This study also tested the model by partial least square techniques after collecting 169 cross-sectional data from food delivery riders in Korea. Findings This study found that both platform labor and shadow work affected platform workers' job burnout. In addition, the results showed that shadow work influenced their turnover intention while platform labor did not affect the turnover intention. Based on the results, this study contributed to relevant researchers who are interested in platform contexts by offering measurable constructs on platform labor and shadow work. In addition, this study could provide practitioners with practical implications on managing platform workers.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.2
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• pp.94-102
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• 2020

Considering that the output voltage and current of a single PV panel are limited in PV power generation, a PV array should be constructed by connecting several PV panels in series and parallel to meet the required voltage/power levels for power generation capacity. When a PV array is partially shaded, the maximum power generation depends on the configuration of a PV array and the presence or absence of blocking diodes. This study considers six PV array configurations and the presence or absence of blocking diodes. An optimum connection structure was proposed to maximize power generation in a partial shadow condition. Results were verified through simulation and an experiment.

• Information Systems Review
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• v.23 no.4
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• pp.165-182
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• 2021

In nowadays, Covid-19 has transformed patterns of consumers' behavior into a non-face-to-face mode. As the patterns of consumption have been digitalized, it has become a daily routine for consumers who perform so-called shadow work, which involves unpaid jobs that they have to do by themselves. In mobile grocery service context, consumers' shadow work could lead to shopping avoidance as well as switching toward other shopping channels. Thus, this study is to examine how consumers' perception of shadow work affect mobile shopping avoidance and switching intention toward other shopping channels. This study collected 283 survey data from online respondents who have experience on subscription services for ordering groceries in online. We also tested our research model by using partial least squares. Based on our results, this study has found that the perception of shadow work had a positive effect on mobile shopping avoidance as well as switching intention. We expect that our findings could contribute to relevant research on shadow work and suggest practical implications for digital platforms dealing with subscription business models

• Informatization Policy
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• v.30 no.4
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• pp.62-88
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• 2023

While the introduction of kiosk has become an essential element, enjoying the effect of labor cost reduction, it has not been able to embrace the senior population due to the digital divide. This study investigated which factors have relationships with conflict over use for kiosk from the viewpoint of shadow work that appears during self-service kiosk use. An analysis of 159 seniors through survey revealed that both technostress and subjective norms had significant relationships with conflict over use for kiosk, and that the perception of shadow work had a partial mediating effect on these relationships. Further, user experience showed a moderating effect on the relationship between technostress and perception of shadow work. These results suggest theoretical and practical implications related to digital shadow work, providing the relevant policy regarding digital inclusion for seniors.

• Asia pacific journal of information systems
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• v.33 no.3
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• pp.603-623
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• 2023

While prior work has conducted individuals' password security behavior, there is a relatively neglect to examine individuals' affect and feelings of password fatigue in password change context. Therefore, this study explicated individuals' affective response to the feelings of password fatigue by drawing on several theoretical lens. Survey data collected from 267 users were used to test the model using partial least square analysis. This study found that feelings of password fatigue positively affected the negative password fatigue-induced affect, and also both the feelings of password fatigue and the negative password fatigue-induced affect were negatively related to attitude toward changing passwords, which in turn, leads to the intention to change passwords. Furthermore, this study found that shadow work recognition negatively moderated the relationship between attitude and behavioral intention. This study could offer a new theoretical perspective to understand an individual's security behavior and provide empirical evidences for practitioners in charge of IT security in organizations.

• Proceedings of the KIPE Conference
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• 2015.11a
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• pp.21-22
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• 2015

The maximum power point of a photovoltaic array alters with changing atmospheric conditions, temperature conditions, shadow conditions, so it is required to track maximum power point. As much as MPPT(Maximum Power Point Tracking) is important in photovoltaic systems, many MPPT techniques have been developed. In this paper, several major existing MPPT methods are comparatively analyzed and novel hybrid MPPT algorithm is proposed. The proposed hybrid MPPT algorithm is developed in combination with traditional MPPT methods to complement each other for improving performance and mitigating partial shading effects. The proposed algorithm is validated by using PISIM simulation tool and experiment in 3kW system.

• Korean Journal of Head & Neck Oncology
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• v.32 no.1
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• pp.37-40
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• 2016

The pilomatricoma is a benign skin neoplasm arising from hair follicle matrix cells, and it comprises approximately 0.12% of all benign skin tumors. It occurs most commonly in head and neck. It usually tends to occur in childhood or school-age. Mainly, it exists in single subcutaneous or intradermal nodule and grows very slowly. The diagnosis is confirmed by histopathologic examination. Histopathologically, it is characterized by basaloid cells, enucleated shadow cells and calcifications in the shadow cell. However, it is rare to present extensive ossification in pilomatricoma. The treatment of choice is wide local excision. A 66-year-old man came to our clinic and he complained of two masses on right parotid tail and posterior neck. We performed excisional biopsy on posterior neck and partial parotidectomy. The pathology of former was pilomatricoma with extensive ossification. We report a rare unique case of pilomatricoma with brief review of literature.

• Korean Chemical Engineering Research
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• v.58 no.3
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• pp.416-423
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• 2020

Majority of over 100 kW capacity photo voltaic (PV) power generation system was constructed on the plate ground of soil. Rarely PV system installed on concrete or building but it usually be under 25 kW capacity. On the soil ground the weeds growen up and it's shadow influenced to decrease of amount of PV power generation. This work analysis the weeds shadow's effect to decrease of PV power generation with 100 kW capacity of real PV power generation system in Yeungnam University, Finally the weed shadow"s influence value through the real field monitoring Data is suggested for give a standard management time of weeds to avoid the negative influence on whole power plant. Moreover the hot spot which is generated by long term partial shallow on PV module also can detected with the result of this work. It also suggested as a standard value of monitoring Data.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.308-310
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• 2005

In recent years, the research and development for the photovoltaic(PV) energy system are making rapidly progress around the world and specially this country, too due the deregulation law for the renewable energy system seems to be born sooner or later. In PV generation system, the partially shaded PV array is the one of the worst case which reduces the efficiency of the total PV generation system. The partial shaded condition is the result of shadowing by cloud and dust building of on the surface of the panel. Some structural elements, such as antennas, booms etc. is also the reason of the shadowing. Even if only a small part of PV is shaded, the overall generation power of PV is significantly decreased. Therefore, several researchers who are focusing on the PV generation system take a time for the research related with the shadowing problem of PV array. In this paper, authors have developed the method which users can achieved the modeling of partially shaded PV array with. With several papers authors have already announced the availability of the EMTDC/PSCAD PV panel model component. This research result is the developed version of the previous papers.