• Journal of the Korean earth science society
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• v.30 no.5
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• pp.671-681
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• 2009

In the equilibrium theory of tides by Newton, tide on the Earth is a phenomenon driven by differential gravity contributed both by the Sun and the Moon. Due to the direct link of the generic tidal effect to the oceanic tides, college students in the earth science education department are exposed to this theory through oceanography lectures as well as astronomy lectures. Common oceanography textbooks adopt a non-inertial reference frame fixed to the Earth in which the fictitious, centrifugal force appears. This has a potential risk to provide misconceptions among students in various aspects including the followings: 1) this is how Newton originally derived the equilibrium theory of tides, and 2) the tide is a phenomenon appearing only in rotating systems. We show that in astronomy, a much simpler description, which employs the inertial frame, is generally used to explain tides and thus causes less confusion. We argue that the description used in astronomy is preferable both in the viewpoints of simplicity and ease of interpretation. Moreover, on a historical basis, an inertial frame was adopted by Newton in Principia to explain tides. Thus, the description used in astronomy is consistent with Newton's original approach. We also present various astrophysical tides which do not comply with the concept of centrifugal force in general. We therefore argue that the description used in oceanography should be compensated by that in astronomy, due to its complexity, historical inconsistency and limited applicability.

• Journal of Yeungnam Medical Science
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• v.34 no.2
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• pp.293-297
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• 2017

Merkel cell carcinoma (MCC) is a rare neuroendocrine tumor that is highly aggressive in nature and indolent in progression. The common risk factors for MCC are senility, prolonged exposure to sunlight, and immune deficient states. Moreover, Merkel cell polyomavirus has recently been characterized to be significantly associated with pathogenesis of MCC, including the expression of Cytokeratin 20 (CK20). Diagnosis is often difficult since histopathological results require a number of differential diagnoses through immunohistochemical (IHC) stains with other cutaneous malignancies. A 67-year-old man presented with a solitary dome-shaped erythematous round mass on the left upper arm for 2 months. Biopsy and IHC studies revealed findings consistent with Merkel Cell Carcinoma of neuroendocrine origin. Common IHC stains usually confirm positive findings for CK20, which is also recognized as the key component in making the diagnosis. We present a CK20 negative MCC in light of expanding the knowledge of unusually stained IHC results in MCC.

• Archives of Plastic Surgery
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• v.37 no.1
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• pp.79-82
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• 2010

Purpose: Carcinosarcomas are rare neoplasms in which both malignant epithelial and mesenchymal elements are identified. We have found only twenty one cases of primary cutaneous carcinosarcoma in the English language literature. Therefore it has been difficult to diagnosis because its unclear etiology and low frequency. Methods: A 31-year-old young man with a protruding mass on his ankle dorsum was examined. The tumor was $7{\times}6{\times}3\;cm$ sized and arose from a burn scar. The mass was wide excised and applied split thickness skin graft. Characteristic pathologic finding was a mixture of squamous cell carcinoma and malignant fibrous histiocytoma. Results: Three months after the operation, the patient died of multiple metastasis to the liver, lung and finally of sepsis despite adjuvant chemotherapy and adjuvant radiotherapy. Conclusion: If a metastatic cutaneous carcinosarcoma is diagnosed, wide excision is required. There should be more aggressive management to minimize the risk of recurrence. Further research into the etiology and pathophysiology of the disease and a more careful differential diagnosis may allow improvement in treatment.

• Journal of Auto-vehicle Safety Association
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• v.5 no.2
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• pp.11-16
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• 2013

This paper presents a unified control algorithm of independent braking and steering for collision avoidance. The desired motion of the vehicle in the yaw plane is determined using the probabilistic risk assessment method based on target state estimation. For the purpose of coordinating the independent braking and steering, a non-linear vehicle model has been developed, which describes the vehicle dynamics in the yaw plane in both linear and extended non-linear ranges of handling. A control allocation algorithm determines the control inputs that minimize the difference between the desired and actual vehicle motions, while satisfying all actuator constraints. The performance of the proposed control algorithm has been investigated via computer simulations conducted using the vehicle dynamics software CARSIM and Matlab/Simulink.

• Korean Journal of Biological Psychiatry
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• v.3 no.1
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• pp.30-36
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• 1996

Tardive dyskinesia is a syndrome of involuntary hyperkinetic abnormal movements that occurs during or shortly after the cessation of neuroleptic drug treatment. Typically, the movements are choreoatheoid. Other movements such as tics and dystonia may be present. Nonetheless, any dyskinesia seen in a neuroleptic-treated patient is not always neuroleptic-induced tardive dyskinesia. The prevalence of tardive dyskinesia varies widely, which reflects many methodological problems, such as differential diagnosis. symptom fluctuation, masking effect of neuroleptics, validated diagnostic criteria. Of suggested risk factors, only old age has been consistently found to be associated with an increased frequency of tardive dyskinesia. Many hypotheses about the pathophysiolgy of tardive kinesia are proposeed, but time-honored ones are not present. No consistently safe and effective treatments are found. Various treatment modalities signifies the general ineffectiveness of these agents for most patients. In general, reduction or cessation of neuroleptics, if possible, is recommended. Remission or improvemets of tardive dyskinesia after neuroleptics withdrawal usually occurs among most patients within three months.

• Journal of Gastric Cancer
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• v.15 no.1
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• pp.68-73
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• 2015

Gastric cancer that mimics a submucosal tumor is rare. This rarity and the normal mucosa covering the protuberant tumor make it difficult to diagnosis with endoscopy. We report two cases of advanced gastric cancer that mimicked malignant gastrointestinal stromal tumors preoperatively. In both cases, the possibility of cancer was not completely ruled out. In the first case, a large tumor was suspected to be cancerous during surgery. Therefore, total gastrectomy with lymph node dissection was performed. In the second case, the first gross endoscopic finding was of a Borrmann type II advanced gastric cancer-like protruding mass with two ulcerous lesions invading the anterior wall of the body. Therefore, subtotal gastrectomy with lymph node dissection was performed. Consequently, delayed treatment of cancer was avoided in both cases. If differential diagnosis between malignant gastrointestinal stromal tumor and cancer is uncertain, a surgical approach should be carefully considered due to the possible risk of adenocarcinoma.

• Journal of the Korean Medical Association
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• v.61 no.11
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• pp.662-669
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• 2018

The cutaneous melanoma has been regarded as rare disease entity in Korea for long time but it shows a silent growth recently. Furthermore the management of cutaneous melanoma including staging system, surgical principle, sentinel lymph node biopsy and subsequent complete node dissection and, most importantly, immunotherapy and target therapy against cutaneous melanoma recently. The incidence of cutaneous melanoma is steadily increasing in Korea but its increase is rapid recent 2 decades to 4.3 times and should be greater soon according to the steeper increase of life expectancy. New staging system proposed by American Joint Committee on Cancer (2017) includes changes in individual TNM category and stage groups, particularly from a prognostic viewpoint. Dermoscopy has been successfully introduced in the differential diagnosis of pigmented skin lesion focusing on cutaneous melanoma by non-invasive simple diagnostic tool. Sentinel lymph node biopsy was a issue of long debate whether survival benefit is real or not. Temporary conclusion about this question is reached after two large scale studies and immediate complete node dissection should be performed in a certain situations. Most important change is drug therapy focusing on immunotherapy and target therapy. Braf- and MEK-inhibitor, immune checkpoint inhibitor and PD-1 blocker has been proved to be effective as a sole or combination regimen against advanced and/or high-risk adjuvant setting of cutaneous melanoma. In conclusion, these remarkable changes will be reviewed shortly here.

• Journal of the Semiconductor & Display Technology
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• v.20 no.3
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• pp.1-5
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• 2021

Sleep apnea refers to a condition in which a person does not breathe during sleep, and is a dangerous symptom that blocks oxygen supply in the body, causing various complications, and the elderly and infants can die if severe. In this paper, we present an algorithm that classifies sleep breathing by analyzing the intensity of breathing with images alone in preparation for the risk of sleep apnea. Only the chest of the person being measured is set to the Region of Interest (ROI) to determine the breathing strength by the differential image within the corresponding ROI area. The adult was selected as the target of the measurement and the breathing strength was measured accurately, and the difference in breathing intensity was also distinguished using depth information. Two videos of sleeping babies also show that even microscopic breathing motions smaller than adults can be detected, which is also expected to help prevent infant death syndrome (SIDS).

• Journal of Positioning, Navigation, and Timing
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• v.10 no.4
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• pp.263-269
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• 2021

The carrier-based differential global navigation satellite system (CD-GNSS) has been garnering significant attention as a promising technology for unmanned vehicles for its high accuracy. The CD-GNSS systems to be used for safety-critical applications should provide a certain level of integrity. The integrity of these systems must be analyzed under various conditions, including fault-free and satellite fault conditions. The systems should be able to detect the faults that can cause large biases on the user position errors and quantify the integrity risk by computing the protection level (PL) to protect the user against the faults that are left undetected. Prior work has derived and investigated the PL for the fault-free condition. In this study, the integrity of the CD-GNSS system under the fault condition is analyzed. The position errors caused by the satellite's fault are compared with the fault-free PL (PL_H0) to verify whether the integrity requirement can be met without computing the PLs for the fault conditions. The simulations are conducted by assuming the ephemeris fault, and the position errors are evaluated by changing the size of the ephemeris faults that missed detection. It was confirmed that the existing fault monitors do not guarantee that the position error under the fault condition does not exceed the PL_H0. Further, the impact of the faults on the position errors is discussed.

• Korea Trade Review
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• v.46 no.4
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• pp.131-148
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• 2021

This study examines how corporate social responsibility (CSR) affects corporate tax avoidance behavior. Using a sample of publicly listed U.S. firms, we find that legal CSR-which is required by law-reduces the level of corporate tax avoidance because this type of CSR reduces information asymmetry between investors and corporate management in such a way that investors are less likely to perceive tax avoidance behavior as a risk. On the other hand, we find that the relationship between normative CSR-which is a voluntary type of CSR behavior-and tax avoidance is not statistically significant. Instead, our additional analysis reveals that normative CSR increases the level of corporate tax avoidance conditional on reporting quality. This study provides meaningful implications to the academic literature and to practitioners. Not only does this study highlight the fact that not all CSR are alike, it highlights that it is important to provide transparent CSR information in order to allow stakeholders to estimate the net effects of firms' CSR activities and tax payment.