86 research outputs found

    The impact of CEO/CFO outside directorships on auditor selection and audit quality

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    We examine whether outside directorships of chief executive officer/chief financial officer (CEO/CFO) and resulting network ties to auditors affect auditor selection decisions and subsequent audit quality. The network ties arise when the CEO/CFO of a firm (home firm) serves as an outside director of another firm that hires an auditor (connected auditor). Using a sample of firms that switch auditors in the post-Sarbanes-Oxley Act period, we find that home firms are more likely to appoint connected auditors. We also find that home firms hiring connected auditors experience a significant decline in subsequent audit quality, compared to those hiring non-connected auditors. Specifically, the increases in the likelihood of misstatements, the magnitude of absolute discretionary accruals, and the propensity to meet or beat earnings benchmarks after home firms appoint connected auditors are significantly greater, compared to those for other firms switching to non-connected auditors. We further find that the decline in audit quality is more pronounced when the network is established at the local office level

    Can COVID-19 mark a tipping point for home-based telework? Conflict between untact technology and rigid institutions in Korea

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    BackgroundPreviously, Korea showed a passive attitude toward home-based telework; however, this stance rapidly changed after the COVID-19 pandemic. Sustaining home-based telework entails adjusting productivity conditions, introducing performance-based evaluations, and modifying employment rules, as required by the Korean Labor Standards Act, which demand the consent of most workers. This study aims to explore the societal and institutional shifts necessary for ongoing home-based telework post-pandemic.MethodsThis study discusses the sustainability of home-based work based on survey data and materials from institutions and previous research. It used data from the Workplace Panel Survey provided by the Korea Labor Institution for 3 years (2015, 2017, and 2019) to examine the status of home-based work and business responses. It also addresses legal issues related to changes in working conditions and worker-management agreements resulting from telework implementation. Legal aspects of telework are explained using relevant sections of Korea’s labor laws.ResultsTo establish home-based telework as a working method relevant to the Fourth Industrial Revolution after the pandemic, essential discussions are needed regarding its fundamental applicability to specific job sectors. Moreover, to activate home-based telework without deteriorating working conditions, achieving agreement between workers and management is imperative. However, legal complexities necessitate systemic changes for effective resolution. For the sustainable continuity of telework, a blend of societal awareness and institutional transformations is indispensable.DiscussionThe growth of home-based telework through untact technology expansion is hindered by inflexible Korean labor laws, judicial precedents, and worker-management relations. The absence of necessary legal and organizational changes could lead Korea to revert to pre-pandemic norms or slow implementation. Initially prevalent in IT, home-based telework has expanded across sectors due to the pandemic. Leading the “new normal,” companies creatively enhance productivity through telework, but rigid systems and outdated cultures could impede post-pandemic progress.ConclusionThe study highlights the need for forward-looking institutional changes and adaptation to advancing technology. It provides valuable insights for organizations and policymakers to optimize work dynamics and enhance employee and employer well-being in the post-COVID-19 era

    Design of a High Performance Earth Imaging Microsatellite

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    Multispectral Earth Imaging Satellite (MEISAT) is SaTReCi’s 100 kg micro satellite which will be adequate to support a high resolution multispectral Earth imaging camera. MEISAT, whose development is currently in progress, is capable of achieving a ground resolution of 8.5 meters with a 47 km swath width and 400 km scan length from its intended orbit of 730 km. The low-cost satellite is also capable of storing 8 Gbits of image data which will be transmitted to ground at 10 Mbps with an X-band transmitter. This paper provides an overview of MEISAT mission operation concept. The mission requirements and the system specifications are also discussed. The paper then describes the overall system configuration. The design of the command and data handling system, the power system, the attitude control system, the RF system, and the payload system is presented

    Intercultural Usage of Mori Folium: Comparison Review from a Korean Medical Perspective

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    Objectives. A review on studies related to the use of Mori folium, the leaves of Morus alba, was conducted with the goal of identifying new clinical applications in Korean medicine. Methods. Global literature search was conducted using three electronic databases up to January 2015 with the term Morus alba and its Korean terms. KM literatures including textbooks and standard pharmacopoeia were separately hand-searched and reviewed to provide comparison. Data were extracted according to predetermined criteria, and clinical uses were standardized with ICD-10 categories. Results. 159 potentially relevant studies were identified, and 18 articles including 12 ethnopharmacologic and 6 clinical studies were finally included in this analysis. Ethnopharmacologic studies from 8 countries provided 17 clinical uses. We found that five out of six clinical trials were related to diabetes and suggested a moderate short-term to mild long-term effect. And 43 Korean texts also provided 156 clinical uses in 35 categories including ocular and respiratory disorders. Discussion and Conclusions. Though majority of the clinical uses were also found in Korean medicine literature, treatment of infertility, jaundice, cognitive disorder, and hyperpigmentation was found to be effective and diabetes with Morus alba was recognized to have clinical importance

    Efficacy and Safety of Guardcel Nasal Packing After Endoscopic Sinus Surgery: A Prospective, Single-Blind, Randomized Controlled Study

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    Objectives Nasal packing after endoscopic sinus surgery is frequently used to control postoperative bleeding, enhance the wound healing process, and prevent lateralization of the middle turbinate, which causes insufficient ventilation. Many biodegradable materials have been developed to reduce pain and mucosal damage during packing removal. The purpose of this study was to compare the efficacy of Guardcel (Genewel Co.) middle meatal packing with a traditional nonabsorbable middle meatal packing, Merocel (Medtronic Xomed), on wound healing and patient satisfaction. Methods In this prospective, single-blind, randomized controlled study, we enrolled 32 consecutive patients (64 nostrils) undergoing bilateral endoscopic sinus surgery at Korea University Guro Hospital from February 2015 to August 2015. Guardcel and Merocel were inserted postoperatively into a randomly assigned side. Objective findings about bleeding, hemostasis, adhesion, and infection were evaluated with nasal endoscopy. Patients’ symptoms including pain and nasal obstruction were evaluated with a visual analog scale. Each evaluation was done at 2–3 days, 1 week, 2 weeks, and 4 weeks after surgery. Results At 2–3 days after endoscopic sinus surgery, the Guardcel side had a significantly less hemostasis time than the Merocel side (P=0.001). During this period, the pain during packing removal was significantly lower on the Guardcel-inserted side than the Merocel-inserted side (P=0.002). At two weeks after surgery, the adhesion score on the Guardcel side was significantly lower than that of the Merocel side (P=0.011). Other parameters during the study follow-up periods were not statistically significant. There were no severe adverse reactions. Conclusion Guardcel, a newly developed packing material, appeared to shorten the hemostasis time and reduce pain sensation at 2–3 days after surgery; it also prevented adhesion formation 2 weeks after surgery when compared with the control. Guardcel can be an effective and safe candidate to replace conventional packing materials after endoscopic sinus surgery

    Privacy-Preserving Federated Model Predicting Bipolar Transition in Patients With Depression:Prediction Model Development Study

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    BACKGROUND: Mood disorder has emerged as a serious concern for public health; in particular, bipolar disorder has a less favorable prognosis than depression. Although prompt recognition of depression conversion to bipolar disorder is needed, early prediction is challenging due to overlapping symptoms. Recently, there have been attempts to develop a prediction model by using federated learning. Federated learning in medical fields is a method for training multi-institutional machine learning models without patient-level data sharing. OBJECTIVE: This study aims to develop and validate a federated, differentially private multi-institutional bipolar transition prediction model. METHODS: This retrospective study enrolled patients diagnosed with the first depressive episode at 5 tertiary hospitals in South Korea. We developed models for predicting bipolar transition by using data from 17,631 patients in 4 institutions. Further, we used data from 4541 patients for external validation from 1 institution. We created standardized pipelines to extract large-scale clinical features from the 4 institutions without any code modification. Moreover, we performed feature selection in a federated environment for computational efficiency and applied differential privacy to gradient updates. Finally, we compared the federated and the 4 local models developed with each hospital's data on internal and external validation data sets. RESULTS: In the internal data set, 279 out of 17,631 patients showed bipolar disorder transition. In the external data set, 39 out of 4541 patients showed bipolar disorder transition. The average performance of the federated model in the internal test (area under the curve [AUC] 0.726) and external validation (AUC 0.719) data sets was higher than that of the other locally developed models (AUC 0.642-0.707 and AUC 0.642-0.699, respectively). In the federated model, classifications were driven by several predictors such as the Charlson index (low scores were associated with bipolar transition, which may be due to younger age), severe depression, anxiolytics, young age, and visiting months (the bipolar transition was associated with seasonality, especially during the spring and summer months). CONCLUSIONS: We developed and validated a differentially private federated model by using distributed multi-institutional psychiatric data with standardized pipelines in a real-world environment. The federated model performed better than models using local data only.</p

    Older Adults’ Avoidance of Public Transportation after the Outbreak of COVID-19: Korean Subway Evidence

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    With the spread of the coronavirus worldwide, nations have implemented policies restricting the movement of people to minimize the possibility of infection. Although voluntary restriction is a key factor in reducing mobility, it has only been emphasized in terms of the effect of governments’ mobility restriction measures. This research aimed to analyze voluntary mass transportation use after the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak by age group to explore how the perception of the risk of infection affected the public transit system. Mass transportation big data of Seoul Metro transportation use in the capital city of Korea was employed for panel analyses. The analysis results showed that in the period with both the highest and lowest number of infections of SARS-CoV-2, users aged 65 years and over reduced their subway use more than people aged between 20 and 64. This study also found that the decrease in subway use caused by the sharp increase of coronavirus disease 2019 (COVID-19) cases was the most prominent among people aged 65 years and over. The results imply that the elders’ avoidance of public transportation affected their daily lives, consumption, and production activities, as well as their mobility

    Integrated Pose Estimation Using 2D Lidar and INS Based on Hybrid Scan Matching

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    Point cloud data is essential measurement information that has facilitated an extended functionality horizon for urban mobility. While 3D lidar and image-depth sensors are superior in implementing mapping and localization, sense and avoidance, and cognitive exploration in an unknown area, applying 2D lidar is inevitable for systems with limited resources of weight and computational power, for instance, in an aerial mobility system. In this paper, we propose a new pose estimation scheme that reflects the characteristics of extracted feature point information from 2D lidar on the NDT framework for exploiting an improved point cloud registration. In the case of the 2D lidar point cloud, vertices and corners can be viewed as representative feature points. Based on this feature point information, a point-to-point relationship is functionalized and reflected on a voxelized map matching process to deploy more efficient and promising matching performance. In order to present the navigation performance of the mobile object to which the proposed algorithm is applied, the matching result is combined with the inertial navigation through an integration filter. Then, the proposed algorithm was verified through a simulation study using a high-fidelity flight simulator and an indoor experiment. For performance validation, both results were compared and analyzed with the previous techniques. In conclusion, it was demonstrated that improved accuracy and computational efficiency could be achieved through the proposed algorithms

    ODPA-CNN: One Dimensional Parallel Atrous Convolution Neural Network for Band-Selective Hyperspectral Image Classification

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    Recently, hyperspectral image (HSI) classification using deep learning has been actively studied using 2D and 3D convolution neural networks (CNN). However, they learn spatial information as well as spectral information. These methods can increase the accuracy of classification, but do not only focus on the spectral information, which is a big advantage of HSI. In addition, the 1D-CNN, which learns only pure spectral information, has limitations because it uses adjacent spectral information. In this paper, we propose a One Dimensional Parellel Atrous Convolution Neural Network (ODPA-CNN) that learns not only adjacent spectral information for HSI classification, but also spectral information from a certain distance. It extracts features in parallel to account for bands of varying distances. The proposed method excludes spatial information such as the shape of an object and performs HSI classification only with spectral information about the material of the object. Atrous convolution is not a convolution of adjacent spectral information, but a convolution between spectral information separated by a certain distance. We compare the proposed model with various datasets to the other models. We also test with the data we have taken ourselves. Experimental results show a higher performance than some 3D-CNN models and other 1D-CNN methods. In addition, using datasets to which random space is applied, the vulnerabilities of 3D-CNN are identified, and the proposed model is shown to be robust to datasets with little spatial information
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