• Journal of the Korean Geotechnical Society
• /
• v.23 no.7
• /
• pp.65-76
• /
• 2007

Recently, there have been many construction projects on soft ground with growth of industry and various construction problems concerning soft soil behavior also have been reported. Especially, foundation piles of abutments and (or) buildings which were constructed on the soft ground have been suffering from a lot of stability problems of inordinary displacement due to lateral flow of soft ground. Although many researches for this phenomena have been carried out, it is still difficult to assess the mechanism of lateral flow on soft ground quantitatively. And reliable design method for judgement of lateral flow occurrence is not established yet. In this study, PNN (probabilistic neural network) and CNN (committee neural network) theories were applied for judgment of lateral flow occurrence based on eat data compiled from Korea and Japan. Predictions of PNN and CNN models for new data which were not used during model development are compared with those predicted by conventional empirical methods. It was found that the developed PNN and CNN models can predict more precise and reliable judgment of lateral flow occurrence than conventional empirical methods.

• Journal of the Korean Regional Science Association
• /
• v.39 no.2
• /
• pp.47-61
• /
• 2023

Satisfaction on the residential environment is a major factor influencing the choice of residence and migration, and is directly related to the quality of life in the city. As online services of real estate increases, people's evaluation on the residential environment can be easily checked and it is possible to analyze their satisfaction and its determining factors based on their evaluation. This means that a larger amount of evaluation can be used more efficiently than previously used methods such as surveys. This study analyzed the residential environment reviews of about 30,000 apartment residents collected from 'Zigbang', an online real estate service in Seoul. The apartment review of Zigbang consists of an evaluation grade on a 5-point scale and the evaluation content directly described by the dweller. At first, this study labeled apartment reviews as positive and negative based on the scores of recommended reviews that include comprehensive evaluation about apartment. Next, to classify them automatically, developed a model by using Bidirectional Encoder Representations from Transformers(BERT), a deep learning-based natural language processing model. After that, by using SHapley Additive exPlanation(SHAP), extract word tokens that play an important role in the classification of reviews, to derive determining factors of the evaluation of the residential environment. Furthermore, by analyzing related keywords using Word2Vec, priority considerations for improving satisfaction on the residential environment were suggested. This study is meaningful that suggested a model that automatically classifies satisfaction on the residential environment into positive and negative by using apartment review big data and deep learning, which are qualitative evaluation data of residents, so that it's determining factors were derived. The result of analysis can be used as elementary data for improving the satisfaction on the residential environment, and can be used in the future evaluation of the residential environment near the apartment complex, and the design and evaluation of new complexes and infrastructure.

• Tunnel and Underground Space
• /
• v.33 no.3
• /
• pp.109-125
• /
• 2023

Disposal repository for high-level radioactive waste secures its safety by means of engineered and natural barriers. The performance of these barriers should be tested and verified through various aspects in terms of short and/or long-term. KAERI has been conducting various in-situ demonstrations in KURT (KAERI Underground Research Tunnel). After completing previous experiment, a conceptual design of an improved in-situ experiment, i.e. K-COIN (KURT experiment of THMC COupled and INteraction), was established and detailed planning for the experiment is underway. Preliminary characterizations were conducted in KURT for siting a K-COIN test site. 15 boreholes with a depth of about 20 m were drilled in three research galleries in KURT and intact rock specimens were prepared for laboratory tests. Using the specimens, physical measurements, uniaxial compression, indirect tension, and triaxial compression tests were conducted. As a result, specific gravity, porosity, elastic wave velocities, uniaxial compressive strength, Young's modulus, Poisson's ratio, Brazilian tensile strength, cohesion, and internal friction angle were estimated. Statistical analyses revealed that there did not exist meaningful differences in intact rock properties according to the drilled sites and the depth. Judging from the uniaxial compressive strength, which is one of the most important properties, all the specimens were classified as very strong rock so that mechanical safety was secured in all the regions.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.43 no.4
• /
• pp.501-510
• /
• 2023

The importance of using construction data is increasing in accordance with the recent trend in the smart construction. However, construction project and maintenance information is distributed on the web, and the existing BIM(Building Information Modeling) information exchange and linking method using IFC(Industry Foundation Classes) cannot support connection with BIM data and web resources. This study aims to establish the BIM-based port facility data integration system using linked data(LD) technology in order to integrate BIM and heterogeneous data in the port maintenance domain. To this end, the port BIM-based ifcOWL and port facility maintenance ontology were designed, and LD was built for the BIM and maintenance information of Busan New Port 2-1 Pier3, a BIM pilot project. In addition, service prototypes such as search, statistics and SPARQL(SPARQL Protocol and RDF Query Language) endpoint functions were implemented using the issued LD. The LD-based information utilization system is expected to improve the reusability of information by converting the existing closed information system into an open system and BIM and maintenance data as a web resource in a standard format.

• Journal of Cadastre & Land InformatiX
• /
• v.53 no.1
• /
• pp.83-105
• /
• 2023

A robot-friendly building certification system was established in 2022 to accommodate the growing number of service robots introduced into buildings. However, this system primarily targeted office buildings, with limitations in applying other functional architectures. To address this problem, we developed a certification model of a robot-friendly environment to extend the existing system to apartment complexes. Using focus group interviews and the analytic hierarchy process, we established 28 evaluating items categorized as (a) architecture and facility design, (b) networks and systems, (c) building operations management, and (d) support for robot activity and other services. These indicators were weighted based on their relative importance within and between categories, resulting in scores ranging from 1 to 18 points and a total of 176 points. According to evaluations with the 28 items, each apartment complex could be graded as "best," "excellent," or "general" based on its total achieved scores. This study is significant, as we present the world's first certification model of a robot-friendly environment for apartment complexes that considers human-robot interactions

• Proceedings of the Korea Water Resources Association Conference
• /
• 2020.06a
• /
• pp.261-261
• /
• 2020

물관리의 기본이 되는 연속적인 유량 자료 확보를 위해서는 정확도 높은 수위-유량 관계 곡선식 개발이 필수적이다. 수위-유량 관계곡선식은 모든 수문시설 설계의 기초가 되며 홍수, 가뭄 등 물재해 대응을 위해서도 중요한 의미를 가지고 있다. 그러나 일반적으로 유량 측정은 많은 비용과 시간이 들고, 식생성장, 단면변화 등의 통제특성(control)이 변함에 따라 구간분리, 기간분리와 같은 비선형적인 양상이 나타나 자료 해석에 어려움이 존재한다. 특히, 국내 하천의 경우 자연적 및 인위적인 환경 변화가 다양하여 지점 및 기간에 따라 세밀한 분석이 요구된다. 머신러닝(Machine Learning)이란 데이터를 통해 컴퓨터가 스스로 학습하여 모델을 구축하고 성능을 향상시키는 일련의 과정을 뜻한다. 기존의 수위-유량 관계곡선식은 개발자의 판단에 의해 데이터의 종류와 기간 등을 설정하여 회귀식의 파라미터를 산출한다면, 머신러닝은 유효한 전체 데이터를 이용해 스스로 학습하여 자료 간 상관성을 찾아내 모델을 구축하고 성능을 지속적으로 향상 시킬 수 있다. 머신러닝은 충분한 수문자료가 확보되었다는 전제 하에 복잡하고 가변적인 수자원 환경을 반영하여 유량 추정의 정확도를 지속적으로 향상시킬 수 있다는 이점을 가지고 있다. 본 연구는 머신러닝의 대표적인 알고리즘들을 활용하여 유량을 추정하는 모델을 구축하고 성능을 비교·분석하였다. 대상지역은 안정적인 수량을 확보하고 있는 한강수계의 거운교 지점이며, 사용자료는 2010~2018년의 시간, 수위, 유량, 수면폭 등 이다. 프로그램은 파이썬을 기반으로 한 머신러닝 라이브러리인 사이킷런(sklearn)을 사용하였고 알고리즘은 랜덤포레스트 회귀, 의사결정트리, KNN(K-Nearest Neighbor), rgboost을 적용하였다. 학습(train) 데이터는 입력자료 종류별로 조합하여 6개의 세트로 구분하여 모델을 구축하였고, 이를 적용해 검증(test) 데이터를 RMSE(Roog Mean Square Error)로 평가하였다. 그 결과 모델 및 입력 자료의 조합에 따라 3.67~171.46로 다소 넓은 범위의 값이 도출되었다. 그 중 가장 우수한 유형은 수위, 연도, 수면폭 3개의 입력자료를 조합하여 랜덤포레스트 회귀 모델에 적용한 경우이다. 비교를 위해 동일한 검증 데이터를 한국수문조사연보(2018년) 내거운교 지점의 수위별 수위-유량 곡선식을 이용해 유량을 추정한 결과 RMSE가 3.76이 산출되어, 머신러닝이 세분화된 수위-유량 곡선식과 비슷한 수준까지 성능을 내는 것으로 확인되었다. 본 연구는 양질의 유량자료 생산을 위해 기 구축된 수문자료를 기반으로 머신러닝 기법의 적용 가능성을 검토한 기초 연구로써, 국내 효율적인 수문자료 측정 및 수위-유량 곡선 산출에 도움이 될 수 있을 것으로 판단된다. 향후 수자원 환경 및 통제특성에 영향을 미치는 다양한 영향변수를 파악하기 위해 기상자료, 취수량 등의 입력 자료를 적용할 필요가 있으며, 머신러닝 내 비지도학습인 딥러닝과 같은 보다 정교한 모델에 대한 추가적인 연구도 수행되어야 할 것이다.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.11 no.2
• /
• pp.131-140
• /
• 2009

It has been repeatedly reported that a drainage system of a drained tunnel is deteriorated. And consequently the water pressure on the lining increases with time. However, little research on the watertight tunnel was found in the literatures. According to field measurements, leakage of the undrained tunnel has increased with time, which is completely opposite to the behavior of the drained tunnel. It is evident that the hydraulic deterioration of the tunnel lining changes the water pressure on the lining and the amount of leakage, thus the design coneept in terms of groundwater is not maintained tightly throughout the life time of the tunnel. The Segment lining is generally constructed as watertight. However, it is frequently reported that the leakage in the segment tunnel increases with time. It is also reported that the leakage is generally concentrated at the joints of the segments. In this study structural and hydraulic interaetion of the segment lining due to the hydraulic deterioration of the segments and the joints is investigated using the numerical modeling method. An electric utility tunnel below groundwater table is considered for the analyses. The effects of hydraulic deterioration of the segment lining are identified in terms of ground loading, water pressure and lining behavior. A remedial grouting measure for leakage is also numerically simulated, and its appropriateness is evaluated.

• Korean Journal of Construction Engineering and Management
• /
• v.24 no.1
• /
• pp.3-11
• /
• 2023

According to the post evaluation scheme in Korea of a public construction project which is more than 30 Billion KRW, project performance is evaluated by investigating outcomes and effects of the construction after the completion of the project. The current post evaluation results can be used for planning and estimating a construction project in the future. However, it is not easy to utilized for an on-going project because the system does not provide the phase-based performance of a project. Although project planning performance is important for project initiation, few attempt has been made to evaluate planning performance in Korea. The purpose of this study is to provide a conceptual performance evaluation of planning performance using preliminary feasibility study conducted by Korea Development Institute. This study developed a planning performance database using data extracted from preliminary feasibility study reports of the completed 354 road construction projects. This study analyzed the performance of the planning stage of road projects by developing absolute metrics such as standard construction cost and standard construction schedule based on a Lane-Km. Using the standard construction cost and schedule metrics, the planning performance was analyzed by project characteristics. The results of this study can be used for phase-based performance evaluation from planning phase to construction phase.

• The Journal of the Convergence on Culture Technology
• /
• v.9 no.3
• /
• pp.391-398
• /
• 2023

This study focuses on the potential for creating spatial and atmospheric effects in small theaters using mobile stage equipment, without being constrained by physical space or theater facilities, for mega musical productions. With the continuous growth of mega musicals in the domestic market, the study analyzes the distribution and sales of musical works in Korea and proposes methods for creating spatial effects in university musical education to facilitate the production of mega musicals in small theaters. The mobile stage equipment is designed based on the principle of the periaktoi, a stage mechanism used in ancient Greek theater and the characteristics of mobile stage equipment used in musicals such as <Notre Dame de Paris> and <Laundry>. The mobile stage equipment is a four-sided column-shaped device, which is applied to the musical <Les Misérables> to derive the potential for creating spatial effects, representing the inner state of characters, and forming the mood of the drama. The study is expected to provide opportunities for performing mega musical productions in university musical education and to contribute to the development of the musical industry and education. The utilization of mobile stage equipment demonstrates the possibility of producing mega musical productions in small theaters.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.28 no.4A
• /
• pp.537-548
• /
• 2008

Recently, the prestressed unbonded concrete structures are increasingly being built. The mechanical behavior of prestressed concrete beams with unbonded tendon is different from that of normal bonded PSC beams in that the increment of tendon stress was derived by whole member behavior. The purpose of the present paper is therefore to evaluate the flexural behavior and to propose the equation of ultimate tendon stress by performing static flexural test according to span/depth, concrete compression strength, reinforcement ratio and the effect of existing bonded tendon. From experimental results, for cracking, yielding and ultimate load, the effect of reinforcement ratio was more effective than concrete compression strength, and the beams having high strength concrete had a good performance than having low concrete, but there was no difference between high strength and low strength. And as L/dp was larger, test beams had a long region of ductility. This means that unbonded tendon has a large contribution after reinforcement yielding. Especially, the equation of ACI-318 was not match with test results and had no correlations. After analysis of test results, the equation of ultimate unbonded tendon stress without slip was proposed, and the proposed equation was well matched with test results. So the proposed equation in this paper will be a effective basis for the evaluation of unbonded tendons without slip, analysis and design.