842 research outputs found

    Analysis of Change in the Wind Speed Ratio according to Apartment Layout and Solutions

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    Apartment complexes in various forms are built in downtown areas. The arrangement of an apartment complex has great influence on the wind flow inside it. There are issues of residents’ walking due to gust occurrence within apartment complexes, problems with pollutant emission due to airflow congestion, and heat island and cool island phenomena in apartment complexes. Currently, the forms of internal arrangements of apartment complexes are divided into the flat type and the tower type. In the present study, a wind tunnel experiment and computational fluid dynamics (CFD) simulation were performed with respect to internal wind flows in different apartment arrangement forms. Findings of the wind tunnel experiment showed that the internal form and arrangement of an apartment complex had significant influence on its internal airflow. The wind velocity of the buildings increased by 80% at maximum due to the proximity effects between the buildings. The CFD simulation for relaxing such wind flows indicated that the wind velocity reduced by 40% or more at maximum when the paths between the lateral sides of the buildings were extended

    Leader's Role in Fostering Creativity: The Creativity Creation Model at KT AIT

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    To achieve innovation, constraints that block the effect of a company's creative culture on innovation and creativity in the organization have to be removed. We propose the creativity creation model that takes account of these constraints and suggest that, to cultivate an innovative climateleaders should receive feedback from innovation performance. To improve creativity and achieve successful innovation, leaders should be involved in every procedure of the model. We explore the three main procedures of the model and present a practical application to the case of a Korean telecommunications company's research and development institute, KT AIT. [ABSTRACT FROM AUTHOR] Copyright of Seoul Journal of Business is the property of Seoul National University, College of Business Administration and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)This research was supported by the Institute of Management Research at Seoul National University

    Third-order exceptional point in an ion-cavity system

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    We investigate a scheme for observing the third-order exceptional point (EP3) in an ion-cavity setting. In the lambda-type level configuration, the ion is driven by a pump field, and the resonator is probed with another weak laser field. We exploit the highly asymmetric branching ratio of an ion's excited state to satisfy the weak-excitation limit, which allows us to construct the non-Hermitian Hamiltonian (HnH)(H_{\textrm{nH}}). Via fitting the cavity-transmission spectrum, the eigenvalues of HnHH_{\textrm{nH}} are obtained. The EP3 appears at a point where the Rabi frequency of the pump laser and the atom-cavity coupling constant balance the loss rates of the system. Feasible experimental parameters are provided.Comment: 9 pages, 6 figure

    Report of a case of ischemic colitis with bilaterally patent internal iliac arteries after endovascular abdominal aneurysm repair

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    During endovascular aneurysm repair (EVAR), interruption of the internal iliac arteries (IIAs) or the inferior mesenteric artery by stents or embolization is thought to cause colon ischemia. To minimize this risk, attempts have been made to preserve the IIAs using iliac branch devices or IIA revascularization. Here we present our experience of colon ischemia after EVAR in a patient with bilaterally patent IIAs without evidence of embolism. A 70-year-old man had abdominal pain and a ruptured abdominal aortic aneurysm was found. We performed EVAR with custom-made tube grafts preserving the bilateral IIAs. On postoperative day 2, the patient complained of abdominal pain, a sigmoidoscopy was performed revealing colon ischemia. On laparotomy, transmural infarction of the sigmoid colon was found and resected. Because IIA preservation cannot guarantee protection against colon ischemia, surgeons should maintain a high level of suspicion and use surveillance liberally after EVAR for early diagnosis of colon ischemia, even if both IIAs are preserved

    Demineralized Bone Matrix, as a Graft Enhancer of Auto-Local Bone in Posterior Lumbar Interbody Fusion

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    Study DesignA case controlled study with prospective data collection.PurposeTo evaluate the early influence and the final consequence of demineralized bone matrix (DBM) on auto-local bone as a graft enhancer in posterior lumbar interbody fusion (PLIF).Overview of LiteratureDBM is known as an osteoinductive material; however, it has not been clearly recognized to enhance auto-local bone with a small amount.MethodsPatients who had a PLIF were allocated into two groups. Group I (70 cases) used auto-local bone chips and group II (44 cases) used DBM as an additive to auto-local bone, 1 mL per a segment. Group selection was alternated. Early assessment was performed by computed tomography at 6 months and final assessment was done by simple radiography after 24 months at least. The degree of bone formation was assessed by 4 grade scale.ResultsThe subjects of both groups were homogenous and had similar Oswestry Disability Index at final assessment. The ratio of auto-local bone chips and DBM was 6:1. The degree of bone formation at 6 months after surgery was superior in group II. However, there was no significant difference between the two groups at the final assessment.ConclusionsDBM was not recognized to enhance auto-local bone with small amount

    Aortic Dissection and Rupture in a Child

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    After developing sudden severe chest pain, an 11-year-old boy presented to the emergency room with chest pain and palpitations and was unable to stand up. The sudden onset of chest pain was first reported while swimming at school about 30 minutes prior to presentation. Arterial blood pressure (BP) was 150/90 mmHg, heart rate was 120/minute, and the chest pain was combined with shortness of breath and diaphoresis. During the evaluation in the emergency room, the chest pain worsened and abdominal pain developed. An aortic dissection was suspected and a chest and abdomen CT was obtained. The diagnosis of aortic dissection type B was established by CT imaging. The patient went to surgery immediately with BP control. He died prior to surgery due to aortic rupture. Here we present this rare case of aortic dissection type B with rupture, reported in an 11-year-old Korean child
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