• KDI Journal of Economic Policy
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• 제28권1호
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• pp.117-144
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• 2006

본 연구는 기초재고스톡이 고정투자 수요에 미치는 영향을 반영하는 '실질완충효과(real buffer effect)'와 기말재고스톡과 고정투자를 위한 자금조달 원천 사이의 대체효과를 반영하는 '재무적 완충효과(financial buffer effect)'가 존재하는가를 1990~2003년 기간 동안 361개 상장 제조기업 자료를 이용하여 분석하였다. 또한 재고스톡과 고정투자 간의 관계가 외환위기 전 후에 차이가 있는가를 아울러 살펴보았다. 먼저 재고스톡과 고정투자 간의 이론적인 연관성을 Bo(2004)의 논문을 통해 살펴본 후, Dynamic GMM-SYS 방법을 이용하여 재고스톡과 고정투자 사이의 구조적 관계를 검정하였다. 전체 기간 및 기간 구분에 따른 추정결과는 기말재고스톡이 고정투자와 음의 관계를 나타내고 있고, 또한 기초재고스톡이 고정투자와 통계적으로 유의한 음의 관계를 보이고 있음도 확인하였다. 이러한 결과는 두 가지 측면에서 해석이 가능하다. 기업은 예상치 못한 높은 수요에 직면했을 때 재고스톡을 완충장치(buffer)로 이용하고 있을 뿐만 아니라 재고투자를 고정투자를 위한 재원의 대비책으로 보유한다는 것이다. 이러한 결과를 통해서 알 수 있는 것은 기업의 의사결정은 생산 및 재고스톡 조정 그리고 고정투자에 대한 의사결정과 재무적 의사결정이 상호 연관되어 있다는 것이다.

• Journal of Korean Neurosurgical Society
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• 제41권2호
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• pp.111-117
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• 2007

Objective : The objective of this study was to validate the effects of a titanium mesh cage and dynamic plating in anterior cervical stabilization after corpectomy. Methods : A retrospective study was performed on 31 consecutive patients, who underwent anterior cervical reconstruction with a titanium mesh cage and dynamic plating, from March 2004 to February 2006. Twenty-four patients had 1-level and 7 had 2-level corpectomies. Ten patients underwent surgery with a cage of 10-mm diameter and 21 with 13-mm diameter. Neurological status and outcomes were assessed according to Odom's criteria. Sagittal angle, coronal angle, settling ratio, sagittal displacement, and cervical lordosis were used to evaluate the radiological outcomes. Results : In overall, 26 [83.9%] of 31 showed excellent or good outcomes. Thirteen percent [4 cases] of the patients developed surgical complications, such as hoarseness, transient dysphagia, or nerve root palsy. Seven [22.6%] patients had reconstruction failure:5 [20.8%] in the 1-level corpectomy group and 2 [28.5%] in the 2-level corpectomy group. Revisions were required in 2 patients with plate pullout due to significant instability. However, none of 5 patients who demonstrated cage displacement or screw pullout, underwent a revision. Radiographs revealed bony consolidation in 96.3% of the patients, including 6 patients with implantation failure during the follow-up period. Conclusion : Based on our preliminary results, the titanium mesh cage and dynamic plating was effective for cervical reconstruction after corpectomy. The anterior cervical reconstruction performed with dynamic plates is considered to reduce stress shielding and greater graft compression that is afforded by the unique plate design.

• 대한기계학회논문집A
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• 제38권11호
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• pp.1193-1199
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• 2014

서비스 로봇이 충돌안전성을 확보한 상태에서 고속 주행 임무를 수행하기 위해서는 동적 장애물의 속도를 고려한 궤적 계획이 필요하다. 정적 장애물만을 고려한 상태에서 궤적을 계획하는 경우 장애물과의 상대속도로 인해서 로봇이 장애물과 충돌할 수 있다. 본 연구에서는 동적 장애물의 속도를 고려한 궤적시간조정기법을 제안한다. 제안된 기법을 통해서 기존에 생성된 궤적의 시간을 조정해서 장애물 회피가 가능한지를 평가할 수 있다. 만일 회피가 불가능할 경우 생성된 경로가 아닌 다른 경로를 선택할 수 있다. 모의 시험 결과를 통해서 제안된 기법을 통해서 짧은 시간 내에 장애물 회피를 수행할 수 있음을 보였다.

• 한국정밀공학회지
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• 제23권12호
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• pp.88-94
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• 2006

In this study, the dynamic impact analysis for the passenger air-bag(PAB) module has been carried out by using FEM to predict the dynamic characteristics of vehicle ride safety against head impact. The impact performance of vehicle air-bag is directly related to the design parameters of passenger air-bag module assembly, such as the tie bar bracket's width and thickness, respectively, However, the product's design of PAB module parameters are estimated through experimental trial and error according to the designer's experience, generally. Therefore, the dynamic analysis of head impact test of the passenger air-bag module assembly of automobile is needed to construct the analytical methodology At first, the FE models, which are consist of instrument panel, PAB Module, and head part, are combined to the whole module system. Then, impact analysis is carried out by the explicit solution procedure with assembled FE model. And the dynamic characteristics of the head impact are observed to prove the effectiveness of the proposed method by comparing with the experimental results. The better optimized impact performance characteristics is proposed by changing the tie bracket's width md thickness of module. The proposed approach of impact analysis will provides an efficient vehicle to improve the design quality and reduce the design period and cost. The results reported herein will provide a better understanding of the vehicle dynamic characteristics against head impact.

• Journal of Korean Neurosurgical Society
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• 제53권3호
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• pp.174-179
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• 2013

Objective : Many studies have investigated paraspinal muscle changes after posterior lumbar surgery, including lumbar fusion. However, no study has been performed to investigate back muscle changes after pedicle based dynamic stabilization in patients with degenerative lumbar spinal diseases. In this study, the authors compared back muscle cross sectional area (MCSA) changes after non-fusion pedicle based dynamic stabilization. Methods : Thirty-two consecutive patients who underwent non-fusion pedicle based dynamic stabilization (PDS) at the L4-L5 level between February 2005 and January 2008 were included in this retrospective study. In addition, 11 patients who underwent traditional lumbar fusion (LF) during the same period were enrolled for comparative purposes. Preoperative and postoperative MCSAs of the paraspinal (multifidus+longissimus), psoas, and multifidus muscles were measured using computed tomographic axial sections taken at the L4 lower vertebral body level, which best visualize the paraspinal and psoas muscles. Measurements were made preoperatively and at more than 6 months after surgery. Results : Overall, back muscles showed decreases in MCSAs in the PDS and LF groups, and the multifidus was most affected in both groups, but more so in the LF group. The PDS group showed better back muscle preservation than the LF group for all measured muscles. The multifidus MCSA was significantly more preserved when the PDS-paraspinal-Wiltse approach was used. Conclusion : Pedicle based dynamic stabilization shows better preservation of paraspinal muscles than posterior lumbar fusion. Furthermore, the minimally invasive paraspinal Wiltse approach was found to preserve multifidus muscles better than the conventional posterior midline approach in PDS group.

• 한국산업융합학회 논문집
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• 제25권2_2호
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• pp.219-232
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• 2022

The aim of this study is to provide the dynamic convergence index that reflected the inherent characteristics of the convergence phenomenon and utilized the nationally-funded R&D projects data, thereby suggesting useful information about the direction of the national convergence R&D strategy. The dynamic convergence index that we suggested was made of two indicators: persistency and diversity. From a time-series perspective, the persistency index, which measures the degree of continuous convergence of multidisciplinary nationally-funded R&D projects, and the diversity index, which measures the degree of binding with heterogeneous research areas. We conducted the empirical experiment with 151,248 convergence R&D projects during the 2015~2021 time period. The results showed that convergence R&D projects in both public health and life sciences appeared the highest degree of persistency. It was presumed that the degree of persistency has increased again due to the COVID-19 pandemic. Meanwhile, the degree of diversity has risen with combining with disciplinary such as materials, chemical engineering, and brain science areas to solve social problems including mental health, depression, and aging. This study not only provides implications for improving the concept and definition of dynamic convergence in terms of persistency and diversity for national convergence R&D strategy but also presented dynamic convergence index and analysis methods that can be practically applied for directing public R&D programs.

• Steel and Composite Structures
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• 제43권1호
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• pp.79-90
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• 2022

In this study, the dynamic behavior of functionally graded layered deep beams with viscoelastic core is investigated including the porosity effect. The material properties of functionally graded layers are assumed to vary continuously through thickness direction according to the power-law function. To investigate porosity effect in functionally graded layers, three different distribution models are considered. The viscoelastically cored deep beam is exposed to harmonic sinusoidal load. The composite beam is modeled based on plane stress assumption. The dynamic equations of motion of the composite beam are derived based on the Hamilton principle. Within the framework of the finite element method (FEM), 2D twelve -node plane element is exploited to discretize the space domain. The discretized finite element model is solved using the Newmark average acceleration technique. The validity of the developed procedure is demonstrated by comparing the obtained results and good agreement is detected. Parametric studies are conducted to demonstrate the applicability of the developed methodology to study and analyze the dynamic response of viscoelastically cored porous functionally graded deep beams. Effects of viscoelastic parameter, porosity parameter, graduation index on the dynamic behavior of porous functionally graded deep beams with viscoelastic core are investigated and discussed. Material damping and porosity have a significant effect on the forced vibration response under harmonic excitation force. Increasing the material viscosity parameters results in decreasing the vibrational amplitudes and increasing the vibration time period due to increasing damping effect. Obtained results are supportive for the design and manufacturing of such type of composite beam structures.

• 대한두개안면성형외과학회지
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• 제25권1호
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• pp.22-26
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• 2024

Background: This study analyzed the demographic characteristics of patients with facial palsy who were treated using either dynamic or static procedures. This study aimed to compare the frequency of procedure implementation and age distribution between the two groups. Methods: This study retrospectively analyzed the medical records of patients treated for facial palsy at a single institution from 2014 to 2022. Among cases included in our study, dynamic procedures involved cross-facial nerve graft and latissimus dorsi or gracilis muscle flap transfer. Static procedures included gold weight insertion, canthopexy, browlift, and thread lift/static slings. Results: Among the 31 patients included in our study, eight (25.8%) incorporated dynamic techniques, and the average age of patients was 44.75 years (range, 24-68 years) with a male to female ratio of 1:4. The remaining 23 patients (74.2%) underwent a static procedure, of which the average age was 59.17 years (range, 23-81 years) which was statistically significantly higher than the average age of 44.75 of dynamic patients (p= 0.013). Regarding the timing of treatment after diagnosis, no patient underwent dynamic procedures more than 20 years after initial diagnosis. A greater diversity in the timing of treatment was observed in the static group. All patients who underwent dynamic procedures were treated using static procedures during the study period. Conclusion: Because aesthetics-based static techniques are typically quick outpatient procedures that can be performed under local anesthesia, our study shows that these are often preferred treatments for all age groups, especially for debilitated or older patients. Further research is required to investigate the long-term functional outcomes of these surgical techniques in a wider population of patients.

• 한국IT서비스학회지
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• 제13권1호
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• pp.23-42
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• 2014

This study investigates the impact of Internet Banking Systems on the business performance of bank. Although Internet Banking Systems were introduced about 15 years ago in Korea, there were few studies which evidenced the relationship between Internet Banking Systems and the performance of banks. For this empirical investigation, this study collected the panel data of 13 domestic banks over 8.5 years and divided the dataset into two parts-the first half period (2003~2007) and the second half period (2008~2011) in order to examine the dynamic changes in the impact of Internet Banking Systems. The fixed-effects panel regression results were different in the two parts of dataset. Internet Banking Systems showed only cost-efficiency impact in the first half period. However, in the second half period, Internet Banking Systems showed positive impact on the bank profitability. Moreover, the dummy variable regarding local bank showed no additional impact on this result, implying that the impact of Internet Banking Systems was still significant for the local banks. The results will deliver managerial interpretation on the value of Internet Banking Systems and additional implication on the strategic planning of Internet Banking Systems for many domestic banks.

• 한국의류산업학회지
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• 제6권5호
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• pp.565-574
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• 2004

The purpose of this study is to investigate the historical background and basic composition of costume of the Baekje period. Main official hats of Baekje include the transformed hat, jougwan and daeryun-style ipsikgwan. Daeryun-style ipsikgwan employed chowha shape in most cases, symbolizing good auspice under the harmony of the male and female principles. Main types of costume of the Baekje period are po, yu, go and sang. The king, governmental officials and the common people all put on po of jikryeong gyoim style. Yu' is classified into two styles, chaksu with the narrow sleeve and daesu with the broad one. 'Go' has two styles, gunggo and gwango. The former is narrow in the breadth of the trouser and the latter, wide. 'Sang' is classified into various style according to whether it contains stripes of many colors, thin wrinkles or thick wrinkles. For the decoration of official hat used in the period of the Three Kingdoms, Baekje employed chowha in shape, Kokuryo, chowha and joik and Shilla, joik. In Baekje, rhythmic patterns of flame were applied to official hats, presenting brilliance. In Shilla, shaking geumyeongrak was used for official hats to show movement. In Kokuryo, such hats used flapping feathers, symbolizing dynamic power. Most necklaces and bracelets of the Baekje period were simple and plain.