• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1655-1658
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• 2003

The application area of parallel mechanism is limited in spite of many advantages of that because the workspace of platform is a very small. Thus enlargement of workspace is important issue in design of parallel mechanism. In this paper a parallel mechanism design method is described using commercial simulation program. Firstly strokes of the assembled parallel mechanism's active joints are simulated from kinetic simulation mode to get required workspace, Secondly, dynamic parameters(velocity, acceleration, force, moment) are simulated for the gravity, friction and exit load. Finally, workspace of moving platform is displayed and workspace of area is simulated by motion analysis. The results of this paper will help engineer to design parallel mechanism with optimize workspace.

• Journal of Multimedia Information System
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• v.6 no.1
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• pp.7-14
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• 2019

This work presents a virtual prototyping design approach for an area-based image stitching hardware. The virtual hardware obtained from virtual prototyping is equivalent to the conceptual algorithm, yet the conceptual blocks are linked to the actual circuit components including the memory, logic gates, and arithmetic units. Through the proposed method, the overall structure, size, and computation speed of the actual hardware can be estimated in the early design stage. As a result, the optimized virtual hardware facilitates the hardware implementation by eliminating trail design and redundant simulation steps to optimize the hardware performance. In order to verify the feasibility of the proposed method, the virtual hardware of an image stitching platform has been realized, where it required 10,522,368 clock cycles to stitch two $1280{\times}1024$ sized images. Furthermore, with a clock frequency of 250MHz, the estimated computation time of the proposed virtual hardware is 0.877sec, which is 10x faster than the software-based image stitch platform using MATLAB.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.5
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• pp.1540-1560
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• 2022

Latest technological innovation in the development of compact lower power radios has led to the explosion of Internet of Things. With Wi-Fi, Zigbee and other physical layer protocols offering short coverage area there was a need for a RF protocol that had a larger coverage area with low power consumption. LoRa offers Long Range with lower power consumption. LoRa offers point to point and point to multipoint connections. with Single hop communication in place the need for routing protocols are eliminated. LoRa Wide Area Network stack can accommodate thousands of nodes under a single LoRa gateway with a single hop communication between the end nodes and LoRaWAN gateway. This paper takes an experimental approach to analyze the basic physical layer parameters of LoRa and the practical coverage offered by a LoRaWAN under highly dense urban conditions with variable topography. The insights gained from the practical deployment of the LoRaWAN network, and the subsequent performance analysis is used to design a novel public utility monitoring platform. The second half of the papers is designing a robust platform to integrate both existing wired sensor water meters, current and future generation wireless water meters. The Common Automated Metering Platform is designed to integrate both wired sensors and wireless (LoRaWAN and Wi-Fi) supported water meters. This integrated platform reduces the number of nodes under each LoRaWAN gateway and thus improves the scalability of the network. This architecture is currently designed to accommodate one utility application but can be modified to integrate multi-utility applications.

• Journal of Dental Rehabilitation and Applied Science
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• v.18 no.4
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• pp.277-288
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• 2002

Seven finite element models were constructed in mandible having single screw-type implant fixture connected to the premolar superstructure, in order to evaluate how the length, diameter and platform shape of a screw-type fixture influence the stress in the supporting tissue around fixtures. Each finite element model was varied in terms of length, diameter, and platform shape of the fixture. In each model, 250N of vertical load was placed on the central pit of an occlusal plane and 250N of oblique load placed on the buccal cusp. The stress distribution in the supporting tissue and the other components was analysed using 2-dimensional finite element analysis and the maximum von Mises stress in each reference area was compared. Under lateral loading, the stress was larger at the abutment/fixture interface, and in the crestal bone, compared to the stress pattern under vertical loading. The amount of stress at the superstructure was similar regardless of the length, diameter and platform shape of a fixture. Around the longer fixture, the stress was decreased at the bone crest and subjacent cancellous bone and increased in the cancellous bone area apical to the fixture. Around the wider fixture, the stress was decreased at the abutment/fixture interface, and the bone crest and increased in the cancellous bone area apical to the fixture. Around the fixture having wider platform, less stress was produced at the abutment/fixture interface and the upper part of the cortical bone, compared to the fixture having standard platform. In conclusion, the stress distribution of the supporting tissue was affected by length, diameter, and platform shape of a fixture, and the fixture which was larger in diameter and length could reduce the stress in the supporting tissues at the bone-fixture interface and bone crest area.

• Wind and Structures
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• v.20 no.6
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• pp.751-761
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• 2015

A multi-platform offshore wind farm is receiving the worldwide attention for the sake of maximizing the wind power capacity and the dynamic stability at sea. But, its wind power efficiency is inherently affected by the interference of wake disturbed by the rotating blades, so its layout should be appropriately designed to minimize such wake interference. In this context, the purpose of this paper is to introduce a layout optimization for multi-platform offshore wind farm consisted of 2.5MW spar-type floating wind turbines. The layout is characterized by the arrangement type of wind turbines, the spacing between wind turbines and the orientation of wind farm to the wind direction, but the current study is concerned with the spacing for a square-type wind farm oriented with the specific angle. The design variable and the objective function are defined by the platform length and the total material volume of the wind farm. The maximum torque loss and overlapping section area are taken as the constraints, and their meta-models expressed in terms of the design variable are approximated using the existing experimental data and the geometry interpretation of wake flow.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.12
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• pp.6098-6104
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• 2012

Currently, dozens of CCTVs are widely used in railway station for monitoring passengers in danger and security areas. The most frequent accidents occur at the platform area where passengers boarding the train. However, It is almost impossible that station operator monitors dozens of CCTV screens and recognizes immediately accidents and handle them. Therefore, railway platform monitoring system using image processing technology which automatically detects platform accidents is needed, and in order to that, preferentially, accurate determination of train state in the platform is required. In the paper, we propose train state detection algorithm for vision based railway platform monitoring system. the proposed algorithm determines four different states i.e. trains approach(IN), departure(OUT), stop(ON), and empty(OFF) of the train, in the platform. To evaluate the proposed algorithm, we present the train detection results for the Seoul Metro Line 4 Dongjak and Namtaeryeong Station.

• The Journal of Information Systems
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• v.31 no.1
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• pp.59-90
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• 2022

Purpose This paper presents a new method of classifying online platforms. It also explains how to apply the framework using case studies and generate new insight about platform strategies and policy development. Design/methodology/approach This paper focuses on the relationship between platforms, especially the hierarchy and power relations, and broadly classifies platforms as follows: content/services, meta information, app stores, operating systems, and cloud. Both the content/service platform and the meta information platform have matching as their main function. However, most content/services tend to collect and access information through meta-information platforms, so meta-information platforms are closer to infrastructure than content/service platforms. App store, operating system, and cloud can be said to be platforms of platforms. A small number of companies in the US and China dominate platforms of platforms, and become the recent development and regulatory targets of their respective governments. Findings We should be wary of the attempts to regulate domestic platforms by importing foreign regulations that ignore the hierarchical structure that our framework highlights. We believe that Korea's strategy to become a true platform powerhouse is clear. As one of the few countries with significant companies in the area of meta information platforms, it will be necessary to fully utilize the position and advance into the strategically important area of platforms of platforms. Furthermore, it is necessary to encourage world-class companies to appear in Korea in the app store, operating system, and cloud. To do so, the government needs to introduce promotion policies to strategically nurture such platforms rather than to regulate them.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.58-58
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• 2022

With the development of advanced technology, automation of agricultural work is spreading. In association with the 4th industrial revolution-based technology, research on field smart farm technology is being actively conducted. A state-of-the-art unmanned automated agricultural production demonstration complex was established in Naju-si, Jeollanam-do. For the operation of the demonstration area platform, it is necessary to build a sophisticated, advanced, and intelligent field smart farming model. For the operation of the unmanned automated agricultural production demonstration area platform, we are building data on the growth of soybean for smart cultivated crops and conducting research to determine the optimal time for agricultural work. In order to operate an unmanned automation platform, data is collected to discover digital factors for water management immediately after planting, water management during the growing season, and determination of harvest time. A subsurface drip irrigation system was established for smart water management. Irrigation was carried out when the soil moisture was less than 20%. For effective water management, soil moisture was measured at the surface, 15cm, and 30cm depth. Vegetation indices were collected using drones to find key factors in soybean production prediction. In addition, major growth characteristics such as stem length, number of branches, number of nodes on the main stem, leaf area index, and dry weight were investigated. By discovering digital factors for effective decision-making through data construction, it is expected to greatly enhance the efficiency of the operation of the unmanned automated agricultural production demonstration area.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.116.4-116
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• 2002

$\textbullet$In case of using overhead camera system, mobile robot moves under static working area. $\textbullet$Mobile robot must use onboard camera system to work under wide working area. $\textbullet$Mobile robot must have wireless LAN to remove restriction of movement. $\textbullet$Onboard camera system must have wireless LAN environment. $\textbullet$We develop embedded vision platform using onboard camera.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.191-194
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• 2005

In this paper the platform system for IEEE 802.15.4 Low Rate WPAN is designed and fabricated. IEEE 802.15.4 Low Rate WP AN system serves the functions and realization of home-area network. According to the IEEE 802.15.4 standard, there are two modes, One is BPSK modulation in 868/915MHz frequency band. The other is O-QPSK modulation in 2.45GHz frequency band. In this paper we implemented the platform system mounted in one PCB board in 868/915MHz frequency band of IEEE 802.15.4 Low Rate WPAN system. We measured that the platform system which consists of digital part and RF part has good performance. Also RF part is realized by design and fabrication of the RF transceiver IC. The key issue is to make the platform system which provides the function of Low Rate WPAN system to meet the requirement of IEEE 802.15.4 standards.