• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제18권3호
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• pp.17-22
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• 2018

This study suggests that 'Will not we use more smartphones while watching TV commercials? Then, will the TV advertising effect decrease due to the distributed concentration?". As a result of the preliminary study, it was confirmed that about 63% of users watching TV commercials use smartphones together. In this study, we propose the possibility of a new mobile advertising service by experimenting and analyzing the effect of high frequency technology based TV advertising linked mobile advertising service. Experimental results show that the response rate of the same content is improved about 9 times as compared with that of the general mobile advertisement when the advertisement of the same content is provided by the TV advertisement interlocking type. It can be confirmed that it is quite effective to provide the same content advertisement to the customers who are in front of the TV at the time of sending the TV advertisement. Therefore, it is expected that various services based on high frequency technology will be activated as a new advertising service that will preserve the effect of TV commercials in the future.

• Journal of the Korean GEO-environmental Society
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• 제5권4호
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• pp.57-63
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• 2004

In general steel sheet piles are used in the containment system, which are vertical barrier systems for waste disposal and landfill purposes, and roads in excavation for temporary structure. This paper presents case study of the use of an interlocking sheet pile for water and containment. Cut-off Z-type sheet pile joints are investigated to determine their permeability from the field test. Four different joint sealing materials are used in field test. The results showed joint permeability is significant time-dependent and joint-dependent. These are explored and conclusions on permeability characteristics of different sealants are noted. A case study gives a design example as well as suggestion on permeability and water tightness can be implemented in using the sheet pile barrier in civil and environment works. From the test results, the effective sealing programs of sheet pile interlocks are suggested.

• Journal of the Korean Association of Geographic Information Studies
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• 제10권1호
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• pp.84-91
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• 2007

As GPS equipments improve, one can acquire GPS data easily in the field. To obtain precise and accurate coordinates, however, post processing is additionally required and the processing needs high degree of skills. Besides, it is very common that we cannot operate processing softwares in the field because the required system environment is usually not prepared. The aim of this study is the development of an internet-based GPS data processing service. For post processing, we used GIPSY developed by JPL. It has many advantages such as obtaining coordinates quickly by using precise or predicted ephemeris. This service proceeds as following orders by interlocking GIPSY software and internet service which is operated on a Linux platform: Users upload the raw data file on the internet, then GIPSY runs automatically and then the user gets the result in the field. We use an Apache web server as the hosting program and PHP scripts are used in coding web pages. The total processing time including data-uploading was around 30 seconds for a 24-hour data with a 30-second sampling rate.

• The Journal of the Korea institute of electronic communication sciences
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• 제12권4호
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• pp.671-678
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• 2017

Recent advances in Internet of Things (IoT) encourage us to use IoT devices in daily living areas. However, as IoT devices are being ubiquitously used, concerns onsecurity and privacy of IoT devices are getting grown. Key management is an important and fundamental task to provide security services. For better security, we should restrict reusing a same key in sequential authentication sessions, but it is difficult to manually update and memorize keys. In this paper, we propose a hardware security module(HSM) for automated key management in IoT devices. Our HSM is attached to an IoT device and communicates with the device. It provides an automated, secure key update process without any user intervention. The secure keys provided by our HSM can be used in the user and device authentications for any internet services.

• Wind and Structures
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• 제26권2호
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• pp.75-87
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• 2018

A large number of low-rise buildings experienced serious roof covering failures under strong wind while few suffered structural damage. Clay and concrete tiles are two main kinds of roof covering. For the tile roof system, few researches were carried out based on Finite Element (FE) analysis due to the difficulty in the simulation of the interface between the tiles and the roof sheathing (the bonding materials, foam or mortar). In this paper, the FE analysis of a single clay or concrete tile with foam-set or mortar-set were built with the interface simulated by the equivalent nonlinear springs based on the mechanical uplift and displacement tests, and they were expanded into the whole roof. A detailed wind tunnel test was carried out at Tongji University to acquire the wind loads on these two kinds of roof tiles, and then the test data were fed into the FE analysis. For the purpose of validation and calibration, the results of FE analysis were compared with the full-scale performance ofthe tile roofs under simulated strong wind impact through one-of-a-kind Wall of Wind (WoW) apparatus at Florida International University. The results are consistent with the WoW test that the roof of concrete tiles with mortar-set provided the highest resistance, and the material defects or improper construction practices are the key factors to induce the roof tiles' failure. Meanwhile, the staggered setting of concrete tiles would help develop an interlocking mechanism between the tiles and increase their resistance.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제42권9호
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• pp.779-788
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• 2014

The satellite should generate electric power efficiently to perform the mission successfully within limited power. For this reason, the electrical power system of LEO satellites usually regulates the power which is generated from the solar cells using MPPT (Maximum Power Point Tracking) method. This paper proposes advanced MPPT algorithm based on the fuzzy logic applied to small CubeSat satellite. The simulation has been performed to confirm the validity of the proposed method by interlocking between MATLAB/Simulink and STK (Systems Tool Kit). The EBA(Energy Balance Analysis) has also been performed at two different pointing modes of KAUSAT-5 for solar irradiation according to the satellite orbit and attitude, and load capacity varied with operation modes by Simulink and STK. The performance of fuzzy logic-based MPPT algorithm was verified through the EBA. The validity of the proposed MPPT algorithm based on the fuzzy logic was also confirmed by comparing with P&O (Perturbation & Observation) algorithm that is general in the MPPT.

• Polymer(Korea)
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• 제29권5호
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• pp.481-485
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• 2005

In this work, the thermal and mechanical properties of vapor grown carbon nanofibers (VGCNFs)-reinforced difunctional epoxy (EP) composites were investigated in the presence of the 0, 0.1, 0.5, 1.0, and $2wt\%$ VGCNFs. The thermal properties of the VGCNFs/EP composites were studied by thermo-mechanical analysis (TMA) and dynamic mechanical analysis (DMA). The mechanical properties of the VGCNFs/EP composites were also examined by universal testing machine (UTM), falling impact test, and the friction and wear tests. From experimental results, the thermal and mechanical properties of the VGCNFs/EP composites were improved with increasing the VGCNFs contents. This was due to the increase of crosslinking structure of the composites, resulting in improving the mechanical interlockings between VGCNFs and epoxy resins in the present composite system.

• International Journal of Highway Engineering
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• 제2권2호
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• pp.129-138
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• 2000

This study presents the mechanical characteristics, such as the permanent deformation and the crack, of the large stone asphalt mixtures. The large stone mixture was studied by Kandhal at NCAT(National Center for Asphalt Technology) in 1989. Japan and Arabian countries adopted the large stone mixture for the pavement construction. The experience and the study results showed that the interlocking of the aggregate system of the large stone mixtures is stable and less dependent on the binder characteristics in high temperature. These properties are known as the rutting resistant parameters. However, the mechanical test results should be supported to prove the benefits of the large stone mixtures. The creep test, resilient modulus tests on three different temperature, wheel tracking test and ravelling tests were conducted to evaluate the performance of the large stone mixtures in this study. The test results were compared with the conventional mixtures and modified asphalt concrete mixtures. The large stone mixtures showed better rutting resistance performance.

• Journal of Internet of Things and Convergence
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• 제8권3호
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• pp.63-68
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• 2022

Due to COVID-19, many paradigm shifts in existing manufacturing facilities and the expansion of non-face-to-face services are accelerating worldwide. A representative technology is digital twin technology. Such digital twin technology, which existed only conceptually in the past, has recently become feasible with the construction of a 5G-based network. Accordingly, this paper designed and implemented a part of the USB process to enable digital twins based on OPC UA communication, which is a standard interlocking structure, between real object objects and virtual reality-based USB process in accordance with this paradigm change. By reflecting the physical characteristics of real objects together, it is possible to simulate real-time synchronization of these with real objects. In the future, this can be applied to various industrial fields, and it is expected that it will be possible to reduce costs for decision-making and prevent dangerous accidents.

• The Journal of Korean Orthopaedic Ultrasound Society
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• 제6권1호
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• pp.1-9
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• 2013

Purpose: The purpose is to perform objective evaluation for rotator cuff using ultrasonography and validate factors influencing cuff integrity as well as efficacy of follow-up ultrasonography after unreamed antegrade intramedullary nailing for humerus fracture. Materials and Methods: Seventeen patients with an average age of $55.7{\pm}18.6$ years underwent antegrade intramedullary nailing for humerus fracture and follow-up ultrasonography of shoulder joint. Mean follow-up period was $43.5{\pm}32.2$ months. Intraoperative evaluation for preoperative cuff tear was performed, of which four cuffs were repaired by single row repair technique. Clinical evaluation included visual analogue scale (VAS), range of motion, Korean Shoulder Scoring System (KSS) and American Shoulder and Elbow Society (ASES) score. Ultrasonographic evaluation was performed on cuff integrity and protrusion of proximal nail tip as well. Radiographic evaluation included time to union, protrusion of proximal nail tip and migration of proximal interlocking screw which could affect shoulder joint function. Results: Mean VAS at last follow-up was $1.65{\pm}1.84$ points. Range of motion showed forward flexion of $137.0{\pm}33.5^{\circ}$, external rotation of $43.5{\pm}12.7^{\circ}$ and internal rotation of $16.4{\pm}2.0^{\circ}$ while KSS score and ASES score were $79.6{\pm}20.7$ and $83.7{\pm}17.0$ points, respectively. Bone union was demonstrated in all cases and average time to union was $3.4{\pm}1.3$ months. Migration of proximal interlocking screw was shown in 6 cases (35%). On ultrasonographic evaluation, there were normal in 8 (47%), weaving in 4 (24%), partial tear in 5 cases (29%), but no complete tear. Protrusion of proximal nail tip was demonstrated in 8 cases (47%) on plain radiographs whereas in 11 cases (65%) on ultrasonography and was associated with increasing age (p=0.038). Ultrasonographic weaving and partial tear was associated with protrusion of proximal nail tip (p=006), but not with repair of preoperative tear (p>0.05). Conclusion: Because weaving and partial tear on ultrasonography originated from protrusion of proximal nail tip, careful insertion of nail and meticulous repair of cuff during operation lead to stable fixation with satisfactory recovery of shoulder function follow-up ultrasonography can be a useful tool for evaluating protrusion of nail tip and rotator cuff tear, of which diagnosis is difficult on plain X-ray after antegrade intramedullary nailing for humerus fracture.