• Korean Journal of Remote Sensing
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• v.13 no.2
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• pp.151-163
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• 1997

In this paper, an algorithm for retrieving soil moisture from measurement of microwave reflection at the end of a coaxial canble is presented. Because the wave reflection from the boundary between air and soil layers depends on the dielectric constant of the soil layer, the dielectric constant can be obtained from measured reflection coefficient. At first, an equivalent circuit for the coaxial probe contaced on the soil surface was chosen with two unknown circuit elements. Then, the unknown circuit elements are obtained experrmentally by measuring the reflection constants of 20 soil samples, and consequently, an empirical formula for computing the dielectric constant from the reflection coefficient is obtained. The dielectric constant is mainly influenced by the soil moisture, and the soil moisture can be computed from the dielecfic constant using an existing empirical formula. HP Network Analyzer 8510C was used to measure the magnitude and the phase of the reflection coeffcient at 4.65 GHz, and the measured data set were used to obtain an empirical formula for computing the dielectric constant. The empirical formula obtained in this study was proven by other soil samples.

• The Journal of the Acoustical Society of Korea
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• v.40 no.2
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• pp.169-175
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• 2021

Recently, an ultrasound hologram and its applications have gained attention in the ultrasound research field. However, the determination technique of transmit signal phases, which generate a hologram, has not been significantly advanced from the previous algorithms which are time-consuming iterative methods. Thus, we applied the deep learning technique, which has been previously adopted to generate an optical hologram, to generate an ultrasound hologram. We further examined the Deep learning-based Holographic Ultrasound Generation algorithm (Deep-HUG). We implement the U-Net-based algorithm and examine its generalizability by training on a dataset, which consists of randomly distributed disks, and testing on the alphabets (A-Z). Furthermore, we compare the Deep-HUG with the previous algorithm in terms of computation time, accuracy, and uniformity. It was found that the accuracy and uniformity of the Deep-HUG are somewhat lower than those of the previous algorithm whereas the computation time is 190 times faster than that of the previous algorithm, demonstrating that Deep-HUG has potential as a useful technique to rapidly generate an ultrasound hologram for various applications.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.204-204
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• 2020

환경부는 기존 대형 강우레이더 관측망에 대한 동해안 지역 관측공백 해소와 집중호우에 의한 재해예방을 목적으로 2기의 전파강수관측소를 삼척과 울진 통고산에 구축 운영하고 있다. 본 연구에서는 삼척 및 울진 전파강수관측소 관측 자료 품질 향상을 위한 다양한 품질 분석 기법을 소개하고 그 결과를 제시한다. 설치된 전파강수관측소의 시스템 특성 중 하나인 Short/Long 펄스 신호에 따른 자료의 연속/불연속성 및 피뢰침에 의한 자료 품질, 그리고 강수에 의한 신호감쇠에 따른 유효관측거리 등을 분석하였다. 이러한 분석을 기반으로 신호보정옵셋 및 피뢰침 위치 등을 조정하여 자료 품질을 향상하였다. 또한 삼척과 울진 전파강수관측소를 대상으로 분포형 비차등위상차 산정 기술을 적용하고 그 결과를 분석하였다. 비차등위상차는 시스템 편차나 우박 등의 영향에서 자유로워 특히 전파강수관측소와 같은 X 밴드 정량강우 추정에서 중요하다. 일반적으로 비차등위상차는 차등위상차에 대한 필터링 기법으로 산출하는데, 이 방법은 약한 강수에 대해 변동성이 크며 지형에코 등에 의해 영향을 크게 받는다는 단점이 있다. 본 연구에서는 일반적인 필터링 기법에 의한 비차등위상차와 분포형 기법을 적용한 비차등위상차에 대해 비교 분석을 하였다. 전파강수관측소 강우 자료를 이용한 분포형 비차등위상차 시험적용 결과 기존 비차등위상차에 비해 정성적으로 우위를 보임을 알 수 있었다.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.339-343
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• 2015

To rapidly recover ceased functionality of a facility after a catastrophic seismic event, critical decisions on facility repair works are made within a limited period of time. However, prolonged damage assessment of facilities, due to massive damage in the surrounding region and the complicated damage judgment procedures, may impede restoration planning. To assist reliable structural damage estimation without a deep knowledge and rapid interactive analysis among facility damage and restoration operations during the approximate restoration project planning phase, we developed a prototype of distributed facility restoration simulations through the use of high-level architecture (HLA) (IEEE 1516). The simulation prototype, in which three different simulations (including a seismic data retrieval technique, a structural response simulator, and a restoration simulation module) interact with each other, enables immediate damage estimation by promptly detecting earthquake intensity and the restoration operation analysis according to estimated damage. By conducting case simulations and experiments, research outcomes provide key insights into post-disaster restoration planning, including the extent to which facility damage varies according to disaster severity, facility location, and structures. Additional insights arise regarding the extent to which different facility damage patterns impact a project's performance, especially when facility damage is hard to estimate by observation. In particular, an understanding of required type and amount of repair activities (e.g., demolition works, structural reinforcement, frame installation, or finishing works) is expected to support project managers in approximate work scheduling or resource procurement plans.

• Journal of Intelligence and Information Systems
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• v.8 no.1
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• pp.119-139
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• 2002

In electronic catalogs, each item is represented as an independent unit while the parts of the item can be composed of a higher level of functionality. Thus, the search for this kind of product database is limited to the retrieval of most similar standard commodities. However, many industrial products need to configure optional parts to fulfill the required specifications. Since there are many paths in finding the required specifications, we need to develop a search system via the configuration process. In this system, we adopt a two-phased approach. The first phase finds the most similar template, and the second phase adjusts the template specifications toward the required set of specifications by the Constraint and Rule Satisfaction Problem approach. There is no guarantee that the most similar template can find the most desirable configuration. The search system needs backtracking capability, so the search can stop at a satisfied local optimal satisfaction. This framework is applied to the configuration of computers and peripherals. Template-based reasoning is basically the same as case-based reasoning. The required set of specifications is represented by a list of criteria, and matched with the product specifications to find the closest ones. To measure the distance, we develop a thesaurus of values, which can identify the meaning of numbers, symbols, and words. With this configuration, the performance of the search by configuration algorithm is evaluated in terms of feasibility and admissibility.

• Clinical and Experimental Reproductive Medicine
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• v.37 no.1
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• pp.41-48
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• 2010

Objectives: The aim of this study was to assess appropriate time to convert intramuscular progesterone support to oral administration for luteal phase support in in vitro fertilization (IVF). Methods: Seventy-six cycles of IVF in which fetal heart beat was identified after treatment were included. Patients underwent controlled ovarian hyperstimulation with GnRH agonist long protocol (n=7) or GnRH antagonist protocol (n=66). Cryopreserved embryo transfer was performed in three cycles. Luteal support was initiated by daily intramuscular injection of progesterone, and after confirmation of fetal heart beat, converted to oral micronized progesterone (Utrogestan, Laboratoires Besins International, France) 300 mg daily before or after 8 gestational weeks. The oral progesterone was continued for 11 weeks. Results: Overall clinical abortion rate was 3.9% (3/76) and mean time to conversion was $8^{+4}$ gestational weeks ($46{\pm}5.8$ days after oocytes retrieval). The abortion rate was 5.6% (1/17) and 3.4% (2/59) in patients with conversion before 7 weeks and after 8 weeks, respectively, which were not statistically significant (p=0.678). The miscarriages were occurred at $9^{+4}$ weeks, $11^{+3}$ weeks and $11^{+4}$ weeks. Conclusion: Sequential luteal support using intramuscular and oral progesterone yields a relatively low clinical abortion rate. If fetal heart beat confirmed, sequential regimen appears to be safe and convenient method to reduce patients' discomfort induced by multiple injections.

• Korean Journal of Construction Engineering and Management
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• v.16 no.3
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• pp.113-122
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• 2015

VE workshop is performed based on VE expert' experiences without retrieving VE data of similar previous projects. Moreover, it usually omitted or applied for the sake of formality due to insufficiently understanding VE function, limited time, space and budget. Even though many studies have established VE databases for retrieving and reusing VE data, VE workshop is still inefficient and ineffective to improve projects' values. With this regard, this study proposes a preliminary prototype for improving VE workshop, which utilizes the state-of-the-art information communication technologies(ICTs) including Building Information Modeling(BIM), Mobile Computing(MC), Network Service System(NSS), and Database Management System(DBMS) for better managing, storing and reusing VE data. The prototype was developed to evaluate advantages and limitations. The results show that the proposed prototype can support visual VE data retrieval from similar previous projects, enhance communication among VE team and save much time and cost comparing to traditional VE. Through this, the productivity of VE workshop can improve efficiently and effectively.

• Journal of Korea Water Resources Association
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• v.55 no.9
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• pp.679-686
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• 2022

As the occurrences of flash floods have increased due to climate change, faster and more accurate precipitation observation using X-band radar has become important. Therefore, the Ministry of Environment installed two dual-pol X-band radars at Samcheok and Uljin. The radar data used in this study were obtained from two different elevation angles and composed to reduce the shielding effect. To obtain quantitative rainfall, quality control (QC), K_DP retrieval, and Hybrid Surface Rainfall (HSR) methods were sequentially applied. To improve the accuracy of the quantitative precipitation estimation (QPE) of the X-band radar, we retrieved parameters for the relationship between rainfall rate and specific differential phase, which is commonly called the R-K_DP relationship; hence, an empirical approach was developed using multiple rain gauges for those two radars. The newly suggested relationship, R = 27.4K^0.81_DP, slightly increased the correlation coefficient by 1% more than the relationship suggested by the previous study. The root mean square error significantly decreased from 3.88 mm/hr to 3.68 mm/hr, and the bias of the estimated precipitation also decreased from -1.72 mm/hr to -0.92 mm/hr for overall cases, showing the improvement of the new method.

• Korean Journal of Construction Engineering and Management
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• v.25 no.1
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• pp.50-61
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• 2024

The market for compact houses is growing due to the demand for floor plans prioritizing user needs. However, clients often have difficulty communicating their spatial requirements to professionals including architects because they lack the means to provide evidence, such as spatial configurations or cost estimates. This research aims to create a framework that can translate sketched data-driven spatial requirements into 3D building components in BIM models to facilitate spatial understanding and provide building performance analysis to aid in budgeting in the early design phase. The research process includes developing a process model, implementing, and validating the framework. The process model describes the data flow within the framework and identifies the required functionality. Implementation involves creating systems and user interfaces to integrate various systems. The validation verifies that the framework can automatically convert sketched space requirements into walls, floors, and roofs in a BIM model. The framework can also automatically calculate material and energy costs based on the BIM model. The developed frame enables clients to efficiently create 3D building components based on the sketched data and facilitates users to understand the space and analyze the building performance through the created BIM models.