• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.4
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• pp.766-771
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• 2008

As the practical range of SAW Device extended into various fields including physical sensor, chemical sensor and ID Tag, the platform for various SAW Devices is required more than ever. While SAW ID or Sensors advanced remarkably, the development of platform which applies to SAW Sensor left much to be desired. Therefore this paper represents the SAW platform in order to use SAW ID such as ID Tag or Sensors more conveniently. The SAW platform consists of a RF module which can recognize SAW ID and a main module which has a hish performance processor in order to process the response signal of SAW ID. The main module which has a high performance processor is designed by GUI environmental type to ensure that users are able to use the platform more easily. In this paper, the SAW platform, which is based on ARM9 core processor, used Windows Embedded CE 6.0 OS which brings friendly interface to users. Also the developers can make less effort to design various applications with sensors.

• Journal of KIISE:Databases
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• v.33 no.3
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• pp.271-281
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• 2006

Recently the need for Location-Based Service (LBS) has increased due to the development and widespread use of the mobile devices (e.g., PDAs, cellular phones, labtop computers, GPS, and RFID etc). The core technology of LBS is a moving-objects database that stores and manages the positions of moving objects. To search for information quickly, the database needs to contain an index that supports both real-time position tracking and management of large numbers of updates. As a result, the index requires a structure operating in the main memory for real-time processing and requires a technique to migrate part of the index from the main memory to disk storage (or from disk storage to the main memory) to manage large volumes of data. To satisfy these requirements, this paper suggests a unified index scheme unifying the main memory and the disk as well as migration policies for migrating part of the index from the memory to the disk during a restriction in memory space. Migration policy determines a group of nodes, called the migration subtree, and migrates the group as a unit to reduce disk I/O. This method takes advantage of bulk operations and dynamic clustering. The unified index is created by applying various migration policies. This paper measures and compares the performance of the migration policies using experimental evaluation.

• Journal of the Korea Society of Computer and Information
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• v.20 no.2
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• pp.99-112
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• 2015

Datum point for displaying location and altitude of point has being advantage usefully in various measurement parts. However, datum point has been increasing loss cases owing to weather changes and stratum changes and neglecting meaninglessly. In this paper, we design and implement a multi electronic measurement system monitoring software with functions such as include maximize utilization of existing measurement datum system as well as collected various environment data and detection stratum changes of surround area. Proposed software is implemented to support that reusability and extensibility of software using object oriented modeling method. Our software supports a GUI for electronic measurement datum point administrator as well as for web user and mobile user. Our system can support a graph GUI for various data analysis and reposition in realtime to database that measured location information and various sensing information to prevent loss of electronic measurement datum point and to detected stratum changes. In addition, we include a QR code and RFID recognition function. Finally, we suggest performance evaluation result to confirm stratum changes detection and GPS location error rate.

• Journal of Korea Society of Industrial Information Systems
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• v.14 no.2
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• pp.23-31
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• 2009

Since 9.11 terrorist attacks against the USA, the new paradigm for "supply chain security" has been established. And at the same time a lot of researches are being made on supply chain security by many foreign companies or research institutes. However, domestically the terms "supply chain security" themselves are not yet familiar, and the paradigm of security are not being used in the logistics, while little researches are being made on them But recently along with development of "ConTracer," a supply chain security technology, which is to be used as the equipment for container cargo transportation safety based on RF1D technology, related researches have begun to be activated. The key issues for the development of equipment for container transportation safety are to obtain both a high recognition rate and enough recognition distance. To this end, this study has tested the ConTracer (433 MHz type and 2.4 GHz type) by using Taguchi Method. According to our test results, in the case of 433 MHz type, it is a little more effective that the reader faces to the front-right side, and in the case of 2.4 GHz, reader direction does not make difference in the view of sensitivity. The test also has proved that it is better that antenna location, as expected, is to be installed on the outside for both types alike.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.7 no.4
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• pp.228-235
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• 2007

The main purpose of this paper is to manage the container property effectively at the container yard by applying the RTLS technology to the field of port logistics. Yet, many kinds of noises happen to be inputted with the distance value(between the reader and the tag) which is to be inputted into the location identification algorithm, which makes the distance value jumped due to the system noise of the ultrasonic sensor module and the measurement noise. The Kalman Filter is widely used to prevent this jump occurrence; the noises are eliminated by using the EKF(Extended Kalman Filter) while considering that the distance information of the ultrasonic sensor is non-linear. Also, the 3D RTLS system at the port container yard suggested in this research is designed not to be interrupted for its ultrasonic transmission by positioning the antenna at the front of each sector of the container where the active tags are installed. We positioned the readers, which function as antennas for location identification, to four places randomly in the absolute coordinate and let the positions of the active tags identified by using the distance data delivered from the active tags. For the location identification algorithm used in this paper, the triangulation measurement that is most used in general is applied and newly reorganized to calculate the position of the container. In the first experiment, we dealt with the error resulting in the angle and the distance of the ultrasonic sensor module, which is the most important in the hardware performance; in the second, we evaluated the performance of the location identification algorithm, which is the most important in the software performance, and tested the noise cancellation effects for the EKF. According to the experiment result, the ultrasonic sensor showed an average of 3 to 5cm error up to $45^{\circ}$ in case of $60^{\circ}$ or more, non-reliable linear distances were obtained. In addition, the evaluation of the algorithm performance showed an average of $4^{\circ}{\sim}5^{\circ}$ error due to the error of the linear distance-this error is negligible for most container location identifications. Lastly, the experiment results of noise cancellation and jump preservation by using the EKF showed that noises were removed in the distance information which was entered from the input of the ultrasonic sensor and as a result, only signal was extracted; thus, jumps were able to be removed and the exact distance information between the ultrasonic sensors could be obtained.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12B
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• pp.1444-1451
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• 2009

This paper first proposes diverse C determining models in the Q algorithm which is proposed in the EPCglobal C1 Gen 2 standard and then compares and analyzes its performance. EPCglobal C1 Gen 2 standard proposes the slot-count (Q) selection algorithm for multiple tag identification environment, but there is no such definition for the C value which modifies the Q value depending on collision or no reply. During the tag anti-collision process, the Q algorithm adds C to the Q when there is a collision and reduces the Q by C when there is no reply. The modified Q value updates new slot-counts for tags which determines the tag identification speed, so the C value is an important factor. However, many researches only intend to increase the tag identification speed by proposing a new method or modifying the Q algorithm without any research about the C value. This paper suggests diverse C models which satisfies the EPCglobal C1 Gen 2 and analyzes their performance in the multi tag identification environment. The result of this paper can be used as an index for future researches on EPCglobal C1 Gen 2 C models and multiple tag identification performance.

• Korean Journal of Construction Engineering and Management
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• v.19 no.4
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• pp.3-11
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• 2018

The Construction Workers Mutual Aid Association is carrying out a number of strategic tasks with the goal of "contributing to improving employment and stabilizing the return of workers to construction workers through employment welfare and retirement deduction services." One of them is the retirement deduction system. The retirement allowance system is a system for the retirement income and livelihood security of construction workers who are not adequately protected by the Labor Standards Act, such as retirement allowances due to the nature of day labor. The Construction Workers Mutual Aid Association has promoted the introduction of electronic manpower management. For the efficient management of the pilot sites and the plans for the future, comprehensive evaluation of the pilot sites as well as the evaluation of the status and operation results of each pilot project site are needed. Therefore, in this study, we will develop performance indicators to evaluate the current state of electronic manpower pilot projects and analyze the actual situation of pilot project sites through actual application, and try to derive future implementation strategies.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.1
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• pp.10-18
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• 2017

In this paper, we designed and implemented a visible light identification(VLID) system consisting of a VLID reader and a tag which backscatters incident lights from the reader. A VLID tag sends its ID to the reader by switching an LCD shutter which is located on its surface. The VLID reader consists of six LEDs and a photodiode(PD). The LEDs emit visible light and a PD located in a center position of LEDs receives backscattered light from the VLID tag. A microcontroller and a commercial liquid crystal display(LCD) shutter for 3D-TV glasses are used to implement a VLID tag. Experiments were conducted to confirm VLID system performance. We successfully demonstrated experiments to send NRZ-OOK signal of 100 bps over a distance of 35 cm at daytime. Also, we suggested the theoretical maximum transmission rate and the various methods to enhance the separation distance between a VLID reader and a tag.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.548-553
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• 2006

Activity-based productivity data can be used as an significant reference in many areas of project management such as performance evaluation and project planning. However, the existence of various factors influencing construction productivity makes it difficult to collect and analyze the productivity data. In the most of the domestic construction sites, there is no systematic method to collect and analyze the productivity data along with information on influencing factors; it is common to heavily rely on experience and intuition of field managers when dealing with construction productivity data. Therefore it is necessary to develop a management system for collecting and utilizing the productivity data as well as the factors influencing construction productivity. The main objective of this research is to define the construction productivity and its influencing factors at the activity level. In addition, methodologies on how to analyze the productivity data and to estimate productivity of future projects are proposed.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.1
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• pp.82-86
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• 2016

This paper proposes a method for the immobilization of motorbike brakes in conjunction with near-field communication (NFC) technology in order to meet the increasing demand for security and convenience of motorbike drivers. We thought about the concept of wireless key, NFC security devices and automatic solenoid valve for setting the lock and unlock module. This paper propose the design and development of an innovative anti-theft alarm system for motorcycles using NFC smart devices based on RFID system, the basis of IoT and AES(advanced encryption standard) encryption Algorithm. The design concept is based on NFC communication strategy between the vehicle and owner. To do this concept, we designed motorcycle smart key system with general-purpose NFC system and the automatic solenoid valve for setting the lock and unlock module. First, we designed control unit and NFC card reader for motorcycle smart key system. Then we propose an AES encryption algorithm and prove that the motorcycle key system is controllable by showing the result of implementing and testing, after installing.