• Phonetics and Speech Sciences
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• v.10 no.3
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• pp.9-18
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• 2018

This paper presents an acoustic and phonological study of the alveolar flaps in American English. Based on the Buckeye Corpus, the flapping tokens produced by twenty men are analyzed at both lexical and post-lexical levels. The data, analyzed with Pratt speech analysis, include duration, F2 and F3 in voicing during the flap, as well as duration, F1, F2, F3, and f0 in the adjacent vowels. The results provide evidence on two issues: (1) The different ways in which voiced and voiceless alveolar stops give rise to neutralized flapping stops by following lexical and post-lexical levels, (2) The extent to which the vowel features (height, frontness, and tenseness) affect flapping sounds. The results show that flaps are affected by pre-consonantal vowel features at the lexical as well as post-lexical levels. Unlike previous studies, this study uses the Praat method to distinguish flapped from unflapped tokens in the Buckeye Corpus and examines connections between the lexical and post-lexical levels.

• Proceedings of the Korean Magnestics Society Conference
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• 2009.12a
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• pp.91-91
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• 2009

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.4
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• pp.876-886
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• 1994

Process design in superplastic forming to produce a Nickel-base jet engine disk has been carried out using the rigid-viscoplastic finite element method. This study aims at deriving systematic procedures in forging of superalloy engine disk, and develops a simple scheme to control strainrate within a range of superplastic deformation during the forging operation. The new process, a pancake type preform being used, is designed to have less manufacturing time, and more even distribution of effective strain in the final product, while the conventional superplastic forging of an engine disk has been produced from a cylindrical billet. The jet engine company, Pratt & Whitney, provided the basic information on the manufacturing process of superplastic forging of a jet engine disk.

• Journal of Power Electronics
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• v.3 no.1
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• pp.49-54
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• 2003

A novel control scheme of using a single electronic drive to synchronize two synchronous motors is investigated analytically. The developed control strategy extends the conventional vector control technology, Specifically, it utilizes the property that the motion of two motors can be independently controlled by the q-axis currents provided the desired q-axis currents can be achieved by adjusting physical armature currents. The latter part is indeed guaranteed by adding a position offset to one of the motors. This work has a potential of cost saving in practice where the cost of drive is a major concern.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10a
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• pp.658-660
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• 1999

Ziv-Lempel 코딩 방식은 문자열이 반복해서 나올 때 뒤에 나오는 문자열을 앞에 나온 문자열에 대한 포인터로 대칭시킴으로써 압축을 한다. 따라서 이 방식을 위해서는 앞서 나온 문자열을 유지하는 사전과 문자열 매칭이 필수적이다. 그래서 이 두 가지에 효율적인 자료구조인 접미사 트리를 Ziv-Lempel 코딩 방식에 적용시키려고, 그 이후에 Fiala, Greene와 Larsson은 각각 McCreight와 Ukkonen의 접미사 트리 생성 알고리즘을 LZ77 코딩에 이용하였다. 접미사 트리를 이용한 Zv-Lempel 코딩에는 만들어진 사전, 즉 접미사 트리와 앞으로 압축될 문자열과의 가장 긴 매치는 찾는 과정이 있다. 이는 단순히 접미사 트리의 루트부터 차례로 검색해 나가도 되지만 이렇게 했을 때 걸리는 시간은 노드에서 자식을 찾는데 걸리는 분기 결정 시간에 의해 좌우된다. 즉 분기에 성형 시간 이상이 걸리면 가장 긴 매치를 찾는데도 역시 선형 시간 이상이 걸린다. 게다가 이 방법은 자기 중복(self-overlapping)의 이점을 살릴 수가 없다. Rodeh, Pratt와 Even은 McCreight의 생성 알고리즘을 이용할 때 가장 긴 매치를 바로 찾을 수 있다는 것을 발견했다. 그러나 Ukkonend의 알고리즘에 대해서는 아직 이러한 방법이 알려지지 않았다. 본 논문에서는 Ukkonen의 알고리즘에 몇가지 작업을 추가하여 전체적으로 선형시간안에 가장 긴 매치를 찾는 방법을 소개한다.

• Journal of Chest Surgery
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• v.54 no.4
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• pp.314-318
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• 2021

In this paper, I present the technique of subxiphoid single-port video-assisted thoracic surgery (VATS) thymectomy for thoracic surgeons to perform this procedure safely. This procedure is indicated for all anterior mediastinal masses and may be extended to lung cancer. The patient is placed in the lithotomy position, and the operator should be on the midline. Below the xiphoid process, a skin incision is made 4-5 cm horizontally at a single thumb's width down. Under two-lung ventilation, CO₂ is insufflated, maintaining 10 mm Hg. The fat tissue and thymic tissue are all resected from the sternum and pericardium between both phrenic nerves using an articulated grasper and an energy device. After retrieval of the mass with a wrap bag, a Jackson-Pratt drain is inserted instead of a chest tube. One of the advantages of this procedure is less postoperative pain than intercostal VATS. The subxiphoid approach can be used for bilateral pneumothorax, bilateral pulmonary metastasectomy, and simple lobectomy for both upper lobes and the right middle lobe.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.21-31
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• 2017

In this paper, the Zynq system-on-chip (SoC) platform is used to design an adaptive noise reduction and edge-detection system using partial reconfiguration. Filters are implemented in a partially reconfigurable (PR) region to provide high computational complexity in real-time, 1080p video processing. In addition, partial reconfiguration enables better utilization of hardware resources in the embedded system from autonomous replacement of filters in the same PR region. The proposed edge-detection system performs adaptive noise reduction if the noise density level in the incoming video sequences exceeds a given threshold value. Results of implementation show that the proposed system improves the accuracy of edge-detection results (14~20 times in Pratt's Figure of Merit) through self-reconfiguration of filter bitstreams triggered by noise density level in the video sequences. In addition, the ZyCAP controller implemented in this paper enables about 2.1 times faster reconfiguration when compared to a PCAP controller.

• Journal of Industrial Convergence
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• v.19 no.6
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• pp.21-35
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• 2021

The purpose of this paper is to examine how demand for labor affects the job seeker's decision on the level of investment in education. In the current paradigm of economic growth in which innovations and technological developments generally weaken the strength demand for labor and increases the uncertainty related to employment, this paper provides a theoretical framework that can be used as a basic framework in understanding the decision of investment in education in varying conditions of demand for labor. The following are the findings of this paper. First, the level of investment in education can generally be regarded to be higher as the demand for labor exacerbates but for the job seekers with a certain characteristic. Second, the Arrow-Pratt absolute risk-aversion measure is the characteristic of the job seeker that determines in what direction the job seeker changes in the level of investment in education, For an arbitrary level of demand for labor there exists a certain threshold which determines the minimum degree of risk-aversion required for the job seeker's Arrow-Pratt should go over to increase the level of education as demand for labor weakens. Third, the job seekers lower the level of education even though the demand condition in labor markets weakens if the compensation function does not depend on the level of education. This is surprising because it turns out that one of the reasons why job seekers invest in education is that they want to be recognized in their compensation for their level of education even when more education still raises the probability of employment.

• Journal of the Korean Society of Radiology
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• v.81 no.6
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• pp.1389-1396
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• 2020

Purpose The aim of this study was to analyze several technical and clinical factors associated with the successful management of postoperative leakage by percutaneous Foley catheter placement. Materials and Methods Thirty-two patients were included in this retrospective study. Postoperative gastrointestinal leakage was diagnosed by computed tomography (CT) and the patients underwent percutaneous Foley catheter placement into the leakage site through Jackson-Pratt tubes or imaging-guided methods. Clinical success was defined as successful Foley catheter removal without symptom recurrence within 1 week and the risk factors for clinical failure were analyzed. Results In all patients, percutaneous Foley catheter placement was successfully achieved without complications. Foley catheter was placed at a median of 10 days (range, 1-68) after the confirmation of leakage on CT. Clinical success was achieved in 26 of the 32 patients (81%). Systemic comorbidity (p < 0.001) and failed oral intake (p = 0.015) were the statistically significant risk factors for clinical failure. Conclusion Percutaneous Foley catheter placement can be considered an effective approach for the management of postoperative bowel leakage. The presence of systemic comorbidity and successful oral diet after Foley catheter placement are significant factors for successful clinical recovery.

• Advances in nano research
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• v.1 no.4
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• pp.219-228
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• 2013

We report on the preparation of iron pyrite ($FeS_2$) using pulsed electron ablation of two targets, namely, a mixture of sulfur and iron compound target, and a natural iron pyrite target. Thin films of around 50 nm in thickness have been deposited on glass substrates under Argon background gas at 3 mTorr, and at a substrate temperature of up to $450^{\circ}C$. The thin films have been analyzed chemically and examined structurally using x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and visible Raman spectroscopy. The morphology and thickness of the films have been assessed using scanning electron microscopy (SEM) and visible spectroscopic reflectance. The preliminary findings, using a synthetic target, show the presence of iron pyrite with increasing proportion as substrate temperature is increased from $150^{\circ}C$ to $250^{\circ}C$. The data have not shown any evidence of pyrite in the deposited films from a natural target.