• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.3
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• pp.378-391
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• 1999

When the time-harmonic plane wave is incident upon a high-contrast spherical cavity in a lossy medium, the incoherent shadow intensity pattern is acquired by averaging out the multi-frequency intensities of the co-polarized total electric field calculated at the measurement plane perpendicular to the propagating direction of the incident wave in the forward direction. In the spherical rotational measurement configuration, an incoherent imaging of the spherical cavity is obtained via the back-projections of the incoherent shadow intensity pattern. This imaging method is validated by imaging an air sphere in the lossy medium of ${\epsilon}_r$ = 2 and $\sigma$ = 0.001, 0.003 S/m and the conditions for obtaining better images are investigated.

• Nuclear Engineering and Technology
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• v.49 no.1
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• pp.277-284
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• 2017

This paper presents the establishment and characterization of a neutron calibration field using a bare $^{252}Cf$ source of low neutron source strength in Vietnam. The characterization of the field in terms of neutron flux spectra and neutron ambient dose equivalent rates were performed by Monte Carlo simulations using the MCNP5 code. The anisotropy effect of the source was also investigated. The neutron ambient dose equivalent rates at three reference distances of 75, 125, and 150 cm from the source were calculated and compared with the measurements using the Aloka TPS-451C neutron survey meters. The discrepancy between the calculated and measured values is found to be about 10%. To separate the scattered and the direct components from the total neutron flux spectra, an in-house shadow cone of 10% borated polyethylene was used. The shielding efficiency of the shadow cone was estimated using the MCNP5 code. The results confirmed that the shielding efficiency of the shadow cone is acceptable.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.4
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• pp.87-93
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• 2003

This paper presents a new harmonics reduction methodology using shadow price. First, we employed shadow price of each bus to reduce harmonics effectively. Second, we developed a new algorithm which can reduce harmonics under limits at PCC and each bus. As a result economical design of filters and its location of the distribution system is possible. This method is applied to the real system, and the usefulness of the method is verified.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.8
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• pp.100-105
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• 2000

In this study the structural design concepts of main parameters of a Cathode Ray Tube(CRT) such as frame spring and shadow mask were proposed to guarantee a failure-proof CRT under mechanical shock. With computer simulation and experiments some information on the structural design concept was obtained as followings: the frame and the shadow mask of the CRT needed designing to increase strength so double-beads shape at the corner of frame was newly designed for it, And the spring which interconnected frame with panel glass was required to deform elastically for the purpose of absorbing the shock energy in the direction of drop. A new type of spring 'twisting spring' was designed to achieve the flexibility in that direction. By using it the deformation energy of a shadow mask could reduced to some degree. To accomplish those simulations commerical codes Pam-Crash and I-DEAS were used and a typical CRT was analyzed as an example to prove the usefulness of this study.

• The Journal of Korea Robotics Society
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• v.16 no.3
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• pp.276-282
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• 2021

The system for recognizing text in natural scenes has been applied in various industries. However, due to the change in brightness that occurs in nature such as light reflection and shadow, the text recognition performance significantly decreases. To solve this problem, we propose an adversarial shadow generation and training algorithm that is robust to shadow changes. The adversarial shadow generation and training algorithm divides the entire image into a total of 9 grids, and adjusts the brightness with 4 trainable parameters for each grid. Finally, training is conducted in a adversarial relationship between the text recognition model and the shaded image generator. As the training progresses, more and more difficult shaded grid combinations occur. When training with this curriculum-learning attitude, we not only showed a performance improvement of more than 3% in the ICDAR2015 public benchmark dataset, but also confirmed that the performance improved when applied to our's android application text recognition dataset.

• Journal of Korean Society for Quality Management
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• v.50 no.3
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• pp.545-570
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• 2022

Purpose: The purpose of this study was to explore dimensions to improve airline non-face-to-face(untact) service quality and identify shadow work dimensions in the digital environment among them. Methods: This study conducted mixed method. First of all, For finding out the dimensions of airline untact service quality, in-depth interviews were conducted from passengers. The collected data through the survey were analyzed using improved importance-performance analysis(IPA). Second, An online survey was conducted to quantitatively analyze user perception about airline untact service quality, and the importance performance of service quality at each dimension was identified through the revised IPA method. Results: The results of this study are as follows; Through in-depth interviews, 11 dimensions found out and 32 measurement items were developed. and then, through the revised IPA analysis, passengers were highly satisfied with "Cleanliness of in-flight service" and "Reliability of self check-in". Also, We found 3 shadow work dimensions such as "Ease of use of self check-in", "Usefulness of self check-in", and "Responsiveness of self check-in". Conclusion: Airline service providers have to keep high-satisfaction services and urgently improve less satisfied services. In particular, the dimensions related to shadow work have to be improved.

• The Journal of Information Systems
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• v.31 no.3
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• pp.109-129
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• 2022

Purpose The purpose of this study is to examine whether customers' shadow work and risk perception have an impact on revisit intention to the fast-food restaurant, with mediating role of different types of attribution tendencies. We also added perceived unfairness in the research model, in order to verify its mediating effect on the relationship between attribution tendencies and revisit intention. Design/methodology/approach Applying the shadow work perspective and attribution theory, we designed a research model to confirm the hypotheses. After collecting the data from 331 customers who have used self-service technology in a fast-food restaurant, we conducted an analysis of measurement model and structural model by using Smart-PLS 3.0. Findings This study confirmed that Forced Use of self-service technology can enhance the tendency of dispositional attribution which would negatively affect perceived unfairness and revisit intention. On the other hand, affective risk perception was proven to affect situational attribution, which positively affects revisit intention.

• Asia pacific journal of information systems
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• v.33 no.2
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• pp.389-417
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• 2023

Social distancing required the use of doorstep delivery for nearly all purchases during the COVID-19 pandemic. Foreign users in Korea are forced to participate in superfluous tasks, leading to an increase in their anxiety and fatigue while online shopping. This study examines how digital shadow work stemming from the language barrier can affect the emotions and behaviors of foreign shoppers that use Korean shopping sites. By interviewing 37 foreign users in Korea, this draft examined their experiences, behaviors, and emotional output, classifying them into 14 codes and seven categories. Using grounded theory, we found that online shoppers' emotions, feelings, experiences, and decision making may be changed in the stages of the pre-use, use, and post-use activities. User responses regarding shadow work and related obstacles can be seen with the continue, discontinue, and optional (occasional use) of Korean online shopping sites. Pleasure and satisfaction come from high efficiency and privileges, whereas anger and disappointment come from poor self-confidence and pessimism. Furthermore, buyer behavior and product orientation are identified as intervening conditions, while the online vs. offline shopping experiences are identified as contextual conditions. In conclusion, language barriers and other factors make online shopping difficult for foreign shoppers, which negatively affects their psychological mechanisms and buying behaviors. The implications from the study findings and future research are also discussed.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.12 no.3
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• pp.34-41
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• 1990

The pilomatricoma (calcifying epithelioma of Malherbe) is rare benign hard, spherical and freely movable cutaneous tumor, which was differentiated from hair cells, particulary hair cortex cells. It is usually occured as a single, asymptomatic, 0.5 cm to 3.0 cm sized, deep seated, firm nodule, covered by normal or pink skin. It arises chiefly in young people, including children, and most often in the head, neck and upper extrimites. The authers experienced a case of pilomatricoma which occured in preauricular region. This case was summarized as follows. 1. 10 years old female has suffered from hard subepidermal mass on preauricular area and she visited our out patient clinic. So we performed surgical extirpation and the excised specimen was pathologically examined. 2. Grossly the tumor measures 2.0 cm in diameter and firm, bosselated, spherical shaped which covered by a thin layer of fibrous tissue. On cut section, it shows spicular gritty surfaces, well encapsulation, interwoven and keratotic lamellae. 3. Histopathologically, the epithelial masses of the tumor are composed of two type of cells, basophilic cells and shodow cells. The basophilic cells resemble hair matrix cells which posses round or elogated, deeply basophilic nuclei and scanty cytoplasm. The shadow cells show a central, unstained shadow at the site of the lost nucleus. Gradual development of basophilic cells into shadow cells can be observed. Foci of calcification are present within the lobule of shadow cells. The stroma of the tumor shows a considerable foreign body giant cell reaction adjacent to the shadow cells. 4. No recurrence was observed until post-operative 40 months.

• Journal of Korea Game Society
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• v.15 no.5
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• pp.99-108
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• 2015

To identify the location of the object and improve the realism in 3D game, shadow mapping is widely used to compute the depth values of vertices in view of the light position. Since the depth value of the shadow map is calculated by the world coordinate, the depth values of the static object don't need to be updated. In this paper, (1) in order to improve the rendering speed, using multiple render targets the depth values of static objects stored only once are separated from those of dynamic objects stored each time. And (2) in order to improve the shadow quality in the quarter view 3D game, the position of the light is located close to dynamic objects traveled along the camera each time. The effectiveness of the proposed method is verified by the experiments according to the different static and dynamics object configuration in 3D game.