• KIPE Magazine
• /
• v.14 no.2
• /
• pp.27-31
• /
• 2009

• JOURNAL OF ELECTRICAL WORLD
• /
• s.404
• /
• pp.77-78
• /
• 2010

• Tunnel and Underground Space
• /
• v.28 no.6
• /
• pp.555-568
• /
• 2018

To perform efficient and safe haulage operations in mines, the condition of unsurfaced roads where dump trucks are moving should be regularly investigated, and systematic maintenance should be carried out according to the results. In this study, we developed a smartphone application that can be used to periodically investigate the unsurfaced road conditions in mines. Using the developed application, necessary data can be easily collected on site to evaluate the condition of unsurfaced roads according to the Unsurfaced Road Condition Index (URCI) evaluation system presented by the US Army Corps of Engineers. The smartphone application was tested at several sections of unsurfaced road in the Ilkwang mine, Busan, Korea. The results showed that the field investigation about 7 factors considered in the URCI evaluation system can be conducted through the user interface screen, and the URCI value can be calculated in the field to evaluate the condition of unsurfaced road. The smartphone application developed in this study can be useful for surveying and evaluating the unsurfaced road conditions at the mine site.

• Journal of the Korean Society of Mineral and Energy Resources Engineers
• /
• v.55 no.6
• /
• pp.604-613
• /
• 2018

In this study, we analyzed the variations in the received signal strength index (RSSI) measured from Bluetooth beacons based on the strength and propagation direction of Bluetooth low energy (BLE) signal. Using a smartphone, we performed field experiments to investigate RSSI variations in the BLE signal transmitted by non-directional and directional beacons in an amethyst mine. In case of non-directional beacons, as the distance between the Bluetooth beacon and smartphone decreased, the RSSI increases, whereas as the BLE signal strength increased, the RSSI average gradually increased. The mean value of RSSI measured from the directional beacons was changed without relation to the facing angle between the Bluetooth beacon and smartphone. The results of this study can be used as basic data for developing a Bluetooth beacon-based proximity warning system for underground mines.

• Journal of Korean Society of Steel Construction
• /
• v.28 no.4
• /
• pp.223-229
• /
• 2016

This study proposes a new technology for a smart damper with flag-shaped behavior using the combination of magnetic friction and rubber springs. The magnet provides friction and, thus, energy dissipation, and the rubber springs with precompression contribute to present self-centering capacity of the damper. To verify their performance, this study conducts dynamic tests of magnet frictional dampers and precompressed rubber springs. For the purpose, hexahedron Neodymium (NdFeB) magnets and polyurethane rubber cylinders are used. In the dynamic tests, loading frequency varies from 0.1 to 2.0 Hz. The magnets provide almost perfect rectangular behavior in force-deformation curve. The rubber springs are tested without or with precompression. The rubber springs show larger rigid force with increasing precompression. Lastly, this study discusses combination of rigid-elastic behavior and friction to generate 'flag-shaped' behavior for a smart damper and suggests how to combine the magnets and the rubber springs to obtain the flag-shaped behavior.

• Journal of Digital Contents Society
• /
• v.19 no.6
• /
• pp.1219-1224
• /
• 2018

Nowaday, smart mobile devices on Internet of Things are required to process and deliver greate amount of data in real-time. Therefore, heterogeneous mult-core architecture such the big.LITTLE core architecture, which shows high energy conservation while guaranteeing high performance, are widely employed on up to date smart mobile devices. The LITTLE cores should be highly utilized to gain higher energy conservation because LITTLE cores have much higher energy efficiency than big cores. In this paper, we propose a core selection algorithm, which tries to firstly assign a real-time task on a LITTLE core rather a big core while the task can be finished within its own deadline. We also perform simulation as performance evaluation to show that our proposed algorithm shows higher energy conservation while guaranteeing the required performance.

• Journal of KIISE
• /
• v.42 no.5
• /
• pp.566-572
• /
• 2015

We proposed a novel energy optimization technique for smartphone GPUs, more aggressively lowering the GPU frequency while obtaining higher energy efficiency with a negligible negative impact on the GPU performance. In order to achieve the Quality of Service (QoS) specified by the smartphone application, the proposed optimization technique employed the minimal acceptable GPU frequency based on average Frames per Second (FPS) for each GPU frequency level. Our experimental results on a smartphone development board showed that the proposed technique can reduce the GPU energy consumption by up to 23% over the default DVFS algorithm with only a 0.45 frame drop.

• Smart Media Journal
• /
• v.9 no.4
• /
• pp.109-117
• /
• 2020

Recently, with the advent of the 4th industrial revolution, digital twins are emerging as an important technology that connects and integrates physical systems and cyber systems. In this article, we analyzed the major requirements of digital twins required for the construction of digital twins of power equipments in the energy field, focusing on the industry 4.0-based Asset Administration Shell(AAS). However, since not so many studies have been conducted yet on a common platform or demonstration model for implementing digital twins both domestically and internationally, digital twin requirements are analyzed with the consideration of digital twinning of power equipment in the energy field. Also, we suggested necessary procedures and specific functions of AAS to establish a smart energy digital twin in the future by analyzing the core requirements necessary for the construction and designing the AAS design for specific power equipment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2011.05a
• /
• pp.593-595
• /
• 2011

본 논문에서는 기존에 전력소비자들의 전기요금을 낮추기 위해 전력사업자가 설치하는 스마트미터(smart meter)에 의존하는 대신 가정 내 PLC(Power Line Communication)망을 활용하여 소비자의 기기별로 에너지모니터링 환경을 구축하여 스마트그리드를 통해 소비자가 얻을 수 있는 많은 혜택을 제공할 수 있는 스마트플러그 기반 AMI 시스템을 개발하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2011.11a
• /
• pp.786-789
• /
• 2011

스마트그리드는 기존의 전력망에 디지털 시스템을 결합함으로써, 전력망의 안정성을 높이는 동시에 신재생 에너지의 활용 및 전력 사용량 분산 등과 같이 전력망의 효율성을 끌어올리는 기술이다. 이 같은 기술은 전력공급원과 각 가정에 연결되어 있는 스마트미터와의 실시간 통신을 통해 전력 데이터를 수집하여 이루어진다. 이렇게 수집된 전력데이터들은 기존의 정보통신기술을 사용하여 전송하고 있다. 이러한 이유로 스마트그리드 환경은 기존의 정보통신기술의 취약점뿐만 아니라 스마트그리드 환경에만 적용되는 보안위협이 예상된다. 따라서 본 논문에서는 이러한 보안위협 중 하나로 전력공급원과 실시간 통신을 하는 스마트미터와 각 가정의 디바이스들 간의 인증기술에 대하여 제안한다.