• International conference on construction engineering and project management
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• 2022.06a
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• pp.1187-1193
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• 2022

A construction site is a highly complex and constantly changing environment, where hazardous areas are difficult to detect if workers lack sufficient knowledge and awareness. Thus, frequent worker safety training is required. Numerous studies on using virtual reality (VR) for safety training were published. While they demonstrate the potential for improving the skills necessary to avoid accidents in the construction industry, they remain difficult to apply at actual construction sites. VR requires specialized hardware and software, limiting workers' access and restricting workers' participation in training sessions. As a result, this paper proposes multiple platforms for immersive virtual reality safety training (VRMP) based on Industry Foundation Classes (IFC) and web technologies such as immersive web (WebXR). The VRMP is compatible with mobile and desktop devices currently by workers and demonstrates scenario models familiar to workers. Also, it reduces development time by utilizing Building Information Models (BIM). Additionally, The VRMP collects data from workers in a virtual environment to assess each worker's safety level, assisting workers in effectively and comfortably gaining a better understanding and raising their awareness. This paper develops a case study based on the VRPM in order to assess its effectiveness.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.2
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• pp.102-114
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• 2021

NDF (No Defect Found) is a phenomenon in which defects have been found in the manufacturing, operation and use of a product or facility, but phenomenon of defects is not reproduced in the subsequent investigation system or the cause of the defects cannot be identified. Recently, with the development of the fourth industrial revolution, convergence of hardware and software technologies in various fields is spreading to products such as aircraft, home appliances, and mobile devices, and the number of parts is increasing due to functional convergence. The application of such convergence technologies and the increase in the number of parts are major factors that lead to an increase in NDF phenomena. NDF phenomena have a significant negative impact on cost, reliability, and reliability for both manufacturers, service providers and operators. On the other hand, due to the nature of NDF phenomena such as difficult and intermittent cause identification and ambiguity in judgment, it is common to underestimate the cost of NDF or fail to take appropriate countermeasures in corporate management. Therefore, in this paper, we propose a methodology for estimating NDF costs by the PAF model which is a quality cost analysis model and ABC (Activity Based Costing) technique. The methodology of this study suggests a detailed procedure and the concept to accurately estimate the NDF costs, using ABC analysis, accounting system information, and IT system data. In addition case studies have validated the methodology. We think this could be a valid methodology to refer to when estimating the cost of other parts. And, it is meaningful to provide important judgment information in the decision-making process based on quality management and ultimately reduce NDF costs by visualizing them separately by major variable factors.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.4
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• pp.363-368
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• 2008

Mobile devices become more complex and harder to manage due to the advance of technologies. In this paper, we designed and implemented the DM Agent based on OMA(Open Mobile Alliance) DM(Device Management) which is a standard for mobile device management. The proposed DM Agent basically can manage parameter configuration through the commands ADD, DELETE, REPLACE and GET currently. Each module of the agent was designed and implemented separately for additional functions such as error reporting and software management. So the additional functions can be added by modifying Adaptor part which processes the management commands instead of modifying other modules which analyze or generate management commands. The DM Agent proposed in this paper is implemented based on WIPI(Wireless Internet Platform for Interoperability), therefore portability of the agent can be improved. In addition, this research can give a development example for dissenminating OMA DM as well as verify functional compatibility of WIPI platform. SK WIPI SDK and a Funambol DM test server are used to test operations of the implemented DM Agent.

• Journal of Broadcast Engineering
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• v.19 no.1
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• pp.14-23
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• 2014

This paper proposed controlling methods for SDN(Software Defined Network) based multiple radio access technology as the solutions of following two issues which were mainly occurred by explosive increasing of video traffic. The first one is a requirement for traffic off-loading caused by 3rd-party video service providers from the mobile network operator's viewpoint. The other one is a provision of high-speed video contents transmission services with low price. Furthermore, the performance evaluation was also conducted on the real test-bed which is composed of OpenStack cloud and SDN technology such as OpenFlow and Open vSwitch. A virtual machine running on the OpenStack provide a video service and the terminal which is able to use multiple radio access technology supports two 2.4GHz WLANs(Wireless Local Area Network) and three 5GHz WLANs, concurrently. Finally, we can get 820Mbps of the maximum transmission speed by using that five WLAN links for the single service at the same time.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.4
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• pp.173-183
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• 2020

In the midst of the aging of underground facilities in urban areas and anxiety about road excavation safety accidents, the Ministry of Land, Infrastructure and Transport began to build Underground Geospatial Infomation Map from 2015 as part of the 「ground subsidence prevention measures」 and efficient use of underground spaces. So, the scope is spreading every year. The current Underground Geospatial Infomation Map information is web-based and is operated in a desktop environment, so it is true that there are some limitations in its use in a field environment such as an excavation construction site. The Underground Geospatial Infomation Map, built and operated in a web-based environment, is a large-scale 3D data. Therefore, in order to service by transmitting data to the field without delay, it is necessary to lighten the Underground Geospatial Infomation Map data. In addition, the current Underground Geospatial Infomation Map is not unified in data formats such as 3DS and COLLADA, and the coordinate system method is also different in relative coordinates and absolute coordinates. In this study, by analyzing domestic and overseas prior research and technical use cases, a mobile Underground Geospatial Infomation Map data format and a lightweight method were presented, and a technology development was conducted to create a mobile underground space integration map in the presented format. In addition, the weight reduction rate was tested by applying 3D data compression technology so that data can be transmitted quickly in the field, and technology was developed that can be used by decompressing 3D data compressed in the field. finally, it aims to supplement the technology experimentally developed in this study and conduct additional research to produce it as software that can be used in the excavation site and use it.

• Tunnel and Underground Space
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• v.33 no.4
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• pp.281-298
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• 2023

Continuous research efforts are being devoted to unmanned mobile platforms for lunar exploration. There is an ongoing demand for real-time information processing to accurately determine the positioning and mapping of areas of interest on the lunar surface. To apply deep learning processing and analysis techniques to practical rovers, research on software integration and optimization is imperative. In this study, a foundational investigation has been conducted on real-time analysis of virtual lunar base construction site images, aimed at automatically quantifying spatial information of key objects. This study involved transitioning from an existing region-based object recognition algorithm to a boundary box-based algorithm, thus enhancing object recognition accuracy and inference speed. To facilitate extensive data-based object matching training, the Batch Hard Triplet Mining technique was introduced, and research was conducted to optimize both training and inference processes. Furthermore, an improved software system for object recognition and identical object matching was integrated, accompanied by the development of visualization software for the automatic matching of identical objects within input images. Leveraging satellite simulative captured video data for training objects and moving object-captured video data for inference, training and inference for identical object matching were successfully executed. The outcomes of this research suggest the feasibility of implementing 3D spatial information based on continuous-capture video data of mobile platforms and utilizing it for positioning objects within regions of interest. As a result, these findings are expected to contribute to the integration of an automated on-site system for video-based construction monitoring and control of significant target objects within future lunar base construction sites.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.8
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• pp.1355-1362
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• 2000

Microstrip antennas are attractive for many applications because of their compact size, low profile, and light weight. Recently, the demand for the miniaturization of the personal communication equipment has been increasing along with the proliferation of personal communication systems. Thus, the development of small antenna has been highly demanded. In this paper, a new technique to reduce the overall dimension of a microstrip antenna with a locally non-homogeneous substrate configuration is proposed. The miniaturized microstrip antenna for a repeater system in a mobile communication cellular band(824~894 MHz) is designed with the proposed technique, and commercialized with low cost, light weight, and small size. Comparison between simulations, based on Agilent Technologies HFSS software, and measurements are provided. The proposed method will be more attractive for a light-weight, small-size, and low-cost microstrip array design. This paper also presents the bandwidth improvement technique for under-coupled microstrip patch antenna with a tuning stub.

• Korean Journal of Artificial Intelligence
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• v.11 no.2
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• pp.19-27
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• 2023

In recent times, an exponential increase in Internet traffic has been observed as a result of advancing development of the Internet of Things, mobile networks with sensors, and communication functions within various devices. Further, the COVID-19 pandemic has inevitably led to an explosion of social network traffic. Within this context, considerable attention has been drawn to research on network traffic analysis based on machine learning. In this paper, we design and develop a new machine learning framework for network traffic analysis whereby normal and abnormal traffic is distinguished from one another. To achieve this, we combine together well-known machine learning algorithms and network traffic analysis techniques. Using one of the most widely used datasets KDD CUP'99 in the Weka and Apache Spark environments, we compare and investigate results obtained from time series type analysis of various aspects including malicious codes, feature extraction, data formalization, network traffic measurement tool implementation. Experimental analysis showed that while both the logistic regression and the support vector machine algorithm were excellent for performance evaluation, among these, the logistic regression algorithm performs better. The quantitative analysis results of our proposed machine learning framework show that this approach is reliable and practical, and the performance of the proposed system and another paper is compared and analyzed. In addition, we determined that the framework developed in the Apache Spark environment exhibits a much faster processing speed in the Spark environment than in Weka as there are more datasets used to create and classify machine learning models.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.546-549
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• 2008

최근 모바일·임베디드 시스템의 품질 향상 노력의 일환으로 하드웨어보다 소프트웨어 개발에 더 관심을 가지며 비중 또한 증가하고 있다. 모바일·임베디드 소프트웨어는 특정 목적을 위해 개발되는 특성으로 인하여 표준화된 개발 프로세스 없이 개발되는 경우가 많다. 또는 기업 자체 개발 방법론으로 개발하거나 알려진 임베디드 소프트웨어 개발방법론으로 개발하기도 한다. 하지만 잦은 요구사항 변경과 시스템의 결함 등 프로젝트의 실패는 줄어들지 않고, 이에 대한 해결책으로 본 논문에서는 모바일·임베디드 개발 프로세스의 개선으로 품질향상이 필요하다고 주장한다. 소프트웨어 프로세스에 있어서 대기업에서는 CMMI 수준 달성을 위한 노력을 꾀하고 있다. 하지만 이 모델은 일반 중소규모 기업에 적용하기에는 부담이 너무 크다는 단점이 있고 비용 또한 만만치 않다. 이에 본 논문에서는 XP의 실천사항을 바탕으로 모바일 임베디드 소프트웨어 개발 프로세스 개선을 위한 프레임워크를 제안한다. 이를 통해 모바일·임베디드 소프트웨어 개발 기업은 제품 품질 향상과 함께 CMMI 수준 달성에 기여·활용하게 된다.

• Journal of Digital Convergence
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• v.16 no.8
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• pp.287-292
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• 2018

It's called masterpieces, which are made up of a lot of enthusiasts by adding a variety of configurations, high game quality, and colorful and realistic graphics. Since many classic games came out and disappear from the game companies, they have been revived in recent years as mobile. Although this phenomenon may have various hardware and software reasons, the present researcher intends to compare and analyze the graphical issues of the characters that can increase the game immersion by the user's autonomous selection among the factors for the immersion of the game. In addition to the birth of one of the most loved characters in the world among the characters of various games, it is considered to be a character who has developed the process of graphic and various expressive production centering on the character called Super Mario which shows various developments than the character in the game history of the world We will present various possibilities of development of game character through comparative analysis and research based on the character.