• KIEAE Journal
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• v.6 no.3
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• pp.11-18
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• 2006

Attention on daylighting should be focused not so much on a simple maximization of the natural light available in a space, as on improving the quality of lighting by ensuring as even but intense distribution of illumination in inner areas. An architectural means of optimal daylight distribution is by using so-called light shelf systems, horizontal shading and redirecting devices. The overall performance of the daylighting system can be improved by the incorporation with electric lighting control devices. This paper aims to exemplify the benefit of daylighting in term of economic consideration. In such a case a reasonable technique to compare system costs is by life-cycle costing. Stated simply, a life-cycle cost represents the total cost of a system over its entire life cycle, that is, the sum of first cost and all future costs. Four different electric lighting system designs are proposed and a lighting control system that is continuously operating according to the level of daylight in the space has been adapted. The result shows clearly that although denser layout of lighting fixtures might be more effective to interface to the level of daylight ceaselessly changeable, its economic benefit may not meet the expected criterion the reason of increased initial investment and maintenance cost for the fixtures and control devices.

• International Journal of Internet, Broadcasting and Communication
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• v.11 no.1
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• pp.27-38
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• 2019

Sensors collect information for Internet of Things (IoT)-based services. However, indoor construction sites have a poor communication environment and many interfering elements that make it difficult to collect sensor information. In this study, a network was constructed between a Bluetooth Low Energy (BLE)-based IoT device based on a serverless IoT framework and a router. This experimental environment was applied to large- and small-scale indoor construction sites. Experiments were performed to test the communication performance of BLE-based IoT devices and routers at indoor construction sites. An analysis of the received signal strength indication (RSSI) graph patterns collected from the communication between the BLE-based IoT devices and routers for different testbed site situation revealed areas with good communication performance and poor communication performance due to interfering factors. The results confirmed that structural components of the building as well as the materials, equipment, and temporary facilities used in indoor construction interfere with the communication performance. Construction project managers will require improved technical knowledge of IoT, such as optimizing the router placement and matching communication between the router and workers, to improve the communication performance for large-scale indoor construction.

• Journal of Information Processing Systems
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• v.17 no.1
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• pp.191-202
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• 2021

In an Internet of Things (IoT)-configured system, each device executes on-chip software. Recent IoT devices require fast execution time of complex services, such as analyzing a large amount of data, while maintaining low-power computation. As service complexity increases, the service requires high-performance computing and more space for embedded space. However, the low performance of IoT edge devices and their small memory size can hinder the complex and diverse operations of IoT services. In this paper, we propose a remote on-demand software code execution unit using the cloudification of on-chip code memory to accelerate the program execution of an IoT edge device with a low-performance processor. We propose a simulation approach to distribute remote code executed on the server side and on the edge side according to the program's computational and communicational needs. Our on-demand remote code execution unit simulation platform, which includes an instruction set simulator based on 16-bit ARM Thumb instruction set architecture, successfully emulates the architectural behavior of on-chip flash memory, enabling embedded devices to accelerate and execute software using remote execution code in the IoT environment.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.11
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• pp.4122-4144
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• 2021

In this fast-paced technological world, the Internet of Things is a ground breaking technology which finds an immense role in the present electronic world which includes different embedded sensors, devices and most other things which are connected to the Internet. The IoT devices are designed in a way that it helps to collect various forms of data from varied sources and transmit them in digitalized form. In modern era of IoT technology data security is a trending issue which greatly affects the confidentiality of important information. Keeping the issue in mind a novel light encryption strategy known as LCB is designed for IoT devices for optimal security. LCB exploits the benefits of Feistel structure and the architectural benefits of substitution permutation network both to give more security. Moreover, this newly designed technique is tested on (Virtex-7) XC7VX330T FPGA board and it takes much little area of 224 GE (Gate Equivalent) and is extremely fast with very less combinational path delay of 0.877 ns. An in-depth screening confirms the proposed work to promise more security to counter cryptographic attacks. Lastly the Avalanche Effect (AE) of LCB showed as 63.125% and 63.875% when key and plaintext (PT) are taken into consideration respectively.

• Journal of the Korean Solar Energy Society
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• v.35 no.2
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• pp.93-101
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• 2015

Zero energy building is a self sufficient building that minimizes energy consumption through passive elements such as insulation, high performance window system and installing of high efficiency HVAC system and uses renewable energy sources. The Korea Government has been strengthening the building energy efficiency standard and code for zero energy building. The building energy performance is determined by the performance of building envelope. Therefore it is important to optimize facade design such as insulation, window properties and shading, that affect the heating and cooling loads. In particular, shading devices are necessary to reduce the cooling load in summer season. Meanwhile, BIPV shading system functions as a renewable energy technology applied in solar control facade system to reduce cooling load and produce electricity simultaneously. Therefore, when installing the BIPV shading system, the length of shadings and angle that affect the electricity production must be considered. This study focused on the facade design applied with BIPV shading system for maximizing energy saving of the selected standard building. The impact of changing insulation on roof and walls, window properties and length of BIPV shading device on energy performance of the building were investigated. In conclusion, energy consumption and electricity production were analyzed based on building energy simulations using energyplus 8.1 building simulation program and jEPlus+EA optimization tool.

• Journal of the Korea Institute of Building Construction
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• v.14 no.5
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• pp.407-413
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• 2014

Appropriate selection of lifting equipments for a high-rise building construction project is one of the important factors to the project's success. Proper position of a tower crane on a construction site is so important to be determined by an expert or an experienced construction manager who draws working range of a tower crane and moves it over 2D(dimensional) site layout plan. 3D CAD, BIM, and virtual reality are is used for building design and construction, but it is not usual to use them for temporary facility planning or selection of a tower crane. This study proposes a suitable method to use augmented reality to select proper position of tower cranes. An augmented reality prototype is implemented by Vuforia and Unity 3D on a smart device to verify the practicability of the proposed method. The prototype application installed on a smart device shows several tower cranes on different markers in a real architectural drawing to locate the proper tower crane.

• Smart Structures and Systems
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• v.34 no.1
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• pp.33-40
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• 2024

We aimed to assess the evolution of small-strain stiffness and relative density in non-compacted embankment layers. We developed embedded type in-situ soil stiffness measurement devices for monitoring small-strain stiffness occurring after filling at a test site and conducted comprehensive laboratory compaction tests using an oedometer cell with a bender element. However, direct comparison is extremely difficult because the shear wave velocity measured in the field and laboratory depend on depth and effective stress, respectively. Therefore, we propose a method for establishing a relationship between effective stress and depth using a compressibility model. In this study, the shear wave velocity measured in the field was compared to the estimated shear wave velocity-depth profiles for completely dry and saturated conditions with different relative densities. The relative density under saturated soil conditions may vary between 50% and 90% and tends to be closer to 95%. Under dry soil conditions, the relative density of the embankment can vary from 30% to 70% and tends to approach 76%. For model validation, the relative density estimated from shear wave velocity-depth profiles was compared to that estimated from DCPI data. In other words, the results analyzed in the context of an effective stress-depth model enable the prediction of engineering properties such as the small-strain stiffness and relative density of embankment layers. This study demonstrates that physics-based data analyses successfully capture the relative density of non-compacted embankment layers.

• Architectural research
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• v.22 no.2
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• pp.41-52
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• 2020

Laboratory buildings with specialized equipment and ventilation systems pose challenges in terms of efficient energy use and initial construction costs. Additionally, lab spaces should have flexible and efficient layouts and provide a comfortable indoor research environment. Therefore, this study aims to identify the correlation between the facade of a building and its interior layout from case studies of energy-efficient research labs and to propose passive energy design strategies for the establishment of an optimal research environment. The case studies in this paper were selected from the American Institute of Architects Committee on the Environment Top Ten Projects and Leadership in Energy and Environmental Design (LEED) certified research lab projects. In this paper, the passive design strategies of space zoning, façade design devices to control heating and cooling loads were analyzed. Additionally, the relationships between these strategies and the interior lab layouts, lab support spaces, offices, and circulation areas were examined. The following four conclusions were drawn from the analysis of various cases: 1) space zoning for grouping areas with similar energy requirements is performed to concentrate similar heating and cooling demands to simplify the HVAC loads. 2) Public areas such as corridor, atrium, or courtyard can serve as buffer zones that employ passive solar design to minimize the mechanical energy load. 3) A balanced window-to-wall ratio (WWR), exterior shading devices, and natural ventilation systems are applied according to the space programming energy requirements to minimize the dependence on mechanical service. 4) Lastly, typical laboratory space zoning categories can be revised, reversed, and even reconfigured to minimize the energy load and adjust to the site context. This study can provide deep insights into various design strategies employed for construction of green laboratories along with intuitive arrangement of various building components such as laboratory spaces, lab support spaces, office spaces, and common public areas. The key findings of this study can contribute towards creating improved designs of laboratory facilities with reduced carbon footprint and greenhouse emissions.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.1067-1074
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• 2022

An architect creates his/her design to meet owner's requirements. Floor plans, perspective drawings, and scale models are used in order for the owner to choose the design. The tools are a little helpful for communication between the architect and the owner in case the owner does not know architecture. The scale models are good, but it is hard to make scale models while design is in progress. 3D CAD is a good tool for communication, but it is time-consuming and requires high-performance computer hardware. Augmented reality is able to show 3D virtual models that are updated by the architect with smart devices such as a smart phone and a tablet PC. The owner frequently reviews the updated design anytime anywhere. This study proposes a method to use augmented reality for architectural design and construction management. The method supports the communication between the owner, the architect and the contractor to review updated designs, and to complete the building project. 3D models expressed in augmented reality are created using SketchUp with 2D drawings for building construction. An Android application implementing augmented reality is developed by Qualcomm Vuforia and Unity on smart devices. Drawings as markers and 3D models are connected in Unity. And functions that temporarily hide unnecessary parts can be implemented in C# programming language. If an owner, an architect, or a contractor looks at a smart phone on a 2D drawing, he/she can identify building elements such as 3D buildings or columns on a screen. This can help communication between them.

• Journal of the Korean Society of Safety
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• v.32 no.6
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• pp.81-88
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• 2017

This study deals with the optimal design of a hybrid control system composed of a combination of active control system and passive control system for effective seismic performance improvement of two adjacent structures. The proposed hybrid control system adopts a configuration of installing an active control device in one building and connecting two adjacent structures with a passive control device so that the one-side active control force can be bi-directionally applied to both buildings through the passive connecting devices. In order to derive the optimal performance of the proposed system, the design parameters of the passive and active control systems were searched using the genetic algorithm. Numerical simulations of 10-story and 8-story buildings have been performed to verify the effectiveness of the proposed technique. For the purpose of comparison, the conventional independent control system with two identical active control systems being installed separately for each structure was also optimally designed and its seismic response has been evaluated as well. From the comparative results of the two control systems, it is demonstrated that the proposed hybrid control system requires larger control force for its one-side active control device than the conventional independent control system does for each of both-side active devices, but quite less than the total control force required for both-side devices of the independent control system, while maintaining similar seismic performance. Therefore, the proposed system is more economical and reliable than the conventional independent control system with two identical active devices.