• 기술혁신학회지
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• 제9권4호
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• pp.796-811
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• 2006

본고에서는 통신시장의 구조를 최대한 반영하면서 투명성, 객관성, 규제 비용, 정책목표 구현 등을 고려한 평가체계를 개발하여, 기존 평가 방법 대비 개선된 새로운 평가 기준을 만들었다. 그리고 국내 이동통신시장에 대해 새로운 평가기준을 적용하여 경쟁상황 평가를 시도하였다. 경쟁상황에 대한 1차 판단 결과 국내 이동통신시장은 지배적 사업자로의 지속적인 쏠림현상이 존재하여 유효경쟁 상태에 있지 않은 것으로 나타났다.

• Journal of the Optical Society of Korea
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• 제8권4호
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• pp.163-167
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• 2004

We propose and demonstrate an external optical modulation method based on TE/TM-mode absorption nulls in a Multiple Quantum Well(MQW) Fabry-Perot laser diode(FP-LD). The center wavelength of the absorption nulls is rapidly shifted to short-wavelength by the small current change(~1mA) in the FP-LD, which can modulate an optical signal with more than 10 dB of extinction ratio(ER). The shift of the center wavelength comes from the refractive index change due to anomalous dispersion and the plasma effect in MQW FP-LD waveguide. Non-inverting and inverting signals are made by TE- and TM-mode absorption nulls at 155.52 Mbps and BERs for the signals are measured.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 추계 학술발표회논문집
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• pp.295-302
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• 2003

A quantitative approach for the retrofit prioritization of bridges is developed based on the damage risk of seismic vulnerable components. In the developed approach, seismic damage risk is estimated in the probabilistic perspectives with an analytical bridge model, which can consider various phenomena found in the seismic behaviors of girder-type bridges and damage models of various vulnerable components. Based on the total cost due to failure of structural components, weighting factors are proposed. Finally, the ranking index and retrofit priority of bridges are estimated from the overall damage risk and weighting factors of bridges. As a result, the retrofit priority of four PSC girder bridges is evaluated by using the proposed approach. The vulnerable components in need of seismic retrofit are selected accordingly. From simulated results, the validity of the proposed approach is verified by comparison with the existing approach. In addition, the proposed approach is found to be appropriate in evaluating the priority of existing bridges.

• Structural Monitoring and Maintenance
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• 제2권3호
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• pp.237-252
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• 2015

This paper addresses the issue of reliability and performance in wireless sensor networks (WSN) based structural health monitoring (SHM), particularly with decentralized damage identification techniques. Two decentralized damage identification algorithms, namely, the autoregressive (AR) model based damage index and the Wiener filter method are developed for structural damage detection. The ambient and impact testing have been carried out on the steel beam structure in the laboratory. Seven wireless sensors are installed evenly along the steel beam and seven wired sensor are also installed on the beam to monitor the dynamic responses as comparison. The results showed that wireless measurements performed very much similar to wired measurements in detecting and localizing damages in the steel beam. Therefore, apart from the usual advantages of cost effectiveness, manageability, modularity etc., wireless sensors can be considered a possible substitute for wired sensors in SHM systems.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2008년도 추계학술대회
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• pp.569-578
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• 2008

The aim of this study is to propose economical safety driving speed index which those are geometric road status; examine the levels of which those cost-benefit of driving fuel expenditure; are search road safety design and operational technology for driving simulators. For the objective, we analyzed the current status of driving fuel expenditure and driving scenarios by the road alignments, and reviewed driving and technical specifications by the geometric types of road according to the implementation, and extended completion. Throughout the result of this study, diverse related driving information provision service, efficiently driving system is expected to be implemented in the national highway design system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권9호
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• pp.3384-3400
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• 2021

With the advent of the data era, people pay much more attention to data corruption. Aiming at the problem that the majority of existing schemes do not support corruption detection of ciphertext data stored in cloud environment, this paper proposes a data corruption detection scheme based on ciphertexts in cloud environment (DCDC). The scheme is based on the anomaly detection method of Gaussian model. Combined with related statistics knowledge and cryptography knowledge, the encrypted detection index for data corruption and corruption detection threshold for each type of data are constructed in the scheme according to the data labels; moreover, the detection token for data corruption is generated for the data to be detected according to the data labels, and the corruption detection of ciphertext data in cloud storage is realized through corresponding tokens. Security analysis shows that the algorithms in the scheme are semantically secure. Efficiency analysis and simulation results reveal that the scheme shows low computational cost and good application prospect.

• 한국컴퓨터정보학회논문지
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• 제24권3호
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• pp.105-112
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• 2019

In this paper, we propose a technique to analyze similarity between SQL queries and to assist integrating similar tables. First, the table information was extracted from the SQL queries through the query structure analyzer, and the similarity between the tables was measured using the Jacquard index technique. Then, similar table clusters are generated through hierarchical cluster analysis method and the co-occurence probability of the table used in the query is calculated. The possibility of integrating similar tables is classified by using the possibility of co-occurence of similarity table and table, and classifying them into an integrable cluster, a cluster requiring expert review, and a cluster with low integration possibility. This technique analyzes the SQL query in practice and analyse the possibility of table integration independent of the existing business, so that the existing schema can be effectively reconstructed without interruption of work or additional cost.

• 보건행정학회지
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• 제29권1호
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• pp.90-97
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• 2019

This study investigated the healthcare status of South Korea and member states of the Organization for Economic Cooperation and Development (OECD). By employing the position value for relative comparison index, healthcare status was measured through the following components: demand, supply, accessibility, quality, and cost. Statistical analysis was conducted through the Mann-Kendall test from analyzing trends from 2000 onwards. Results showed that while Korea, on average, scores higher than the OECD average in most of the investigated components, it is below average in certain indexes including primary care and mental health care. Considering the various health issues that have been raised about these indexes, it is important these components be improved upon by policy-makers.

• Journal of Korea Trade
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• 제23권4호
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• pp.115-130
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• 2019

Purpose - This paper examines the impact of labor market regulations on FDI and the production of foreign firms. Design/methodology - We use an index of employment protection along with data on the FDI and production of foreign affiliates that are provided by the OECD. Findings - The empirical results show that strict employment protection discourages both the production and initial entry of foreign firms, with its impact on production being larger than that on the initial entry decision. The result is robust to various specifications in which instrumental variable estimations are used by applying a unionization rate and a severance pay for redundancy dismissal as instruments, respectively. Therefore, policymakers should not limit their focus to tax incentives, cash grants, and relaxation of market regulations, but they should also extend their attention to labor market deregulation and decreasing non-wage cost to attract more foreign firms into their countries. Originality/value - This paper attempts to answer the question on the impact of employment protection rules on the foreign firm's decisions regarding production as well as initial entry.

• International Journal of Advanced Culture Technology
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• 제10권4호
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• pp.555-560
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• 2022

In this study, the insertion loss and phase delay according to the multi-layer structure radome parameters were analyzed using the boundary value solution approach, and the multi-layer structure and hexa mesh structures with low-loss electrical characteristics for the Ku-band transmission/reception frequency of 10.7 ~ 14.5 GHz were designed and manufactured. A hexa mesh was applied to minimize radio wave transmission and scattering, which lowered the transmittance refractive index according to the radio incident angle and minimized dielectric loss through high-density foam. Similar to the simulation result, the transmission loss obtained the gain in a specific receiving frequency band, and in the transmission frequency band, an excellent low loss characteristic was obtained with an insertion loss of 0.8dB or less. The results of this study can be used in radio transmission radomes of low-weight, low-cost end-system protection devices.