• Journal of Sensor Science and Technology
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• v.27 no.2
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• pp.112-117
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• 2018

In this study, a bender-type piezoelectric energy harvester was fabricated and evaluated to compensate for the disadvantages of high-power generation only in the resonance frequency range of a piezoelectric harvester using a piezoelectric cantilever. The generated power was investigated according to various changes in the vibration environment. Compared with the piezoelectric cantilever module, the bender-type piezoelectric module showed a larger number of peak voltages. The primary peak voltage shifted toward the low frequency when the spring was coupled to the bender-type piezoelectric module. The harvester of the three bender-type modules had a vibration frequency exceeding 1 mW in the 34-45 Hz range and generated 3.112 mW of power at the vibration frequency of 38 Hz. The harvester of the six bender-type modules had a vibration frequency exceeding 1 mW in the 31-45 Hz range and generated 3.081 mW of power at the vibration frequency of 35 Hz.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.8
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• pp.1851-1858
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• 2004

The goal of this paper is to develop a production management system based on XML that exclusively applies to a production line of machine-parts. This paper aims to develop the related management modules and integrate them into the production management system based on XML technology. In terms of the implementation of the client/server database module, it develops the GUI application program that supports the communication between the subsystem that controls machine-parts and the server-side database. By developing the RPC emulator, the system remotely executes server module in the client GUI module. By developing the integration control module that integrates the independently executed modules, it controls the production management system that works as a single organic management system and by developing the POP system, it builds the information system of machine-parts performance records. This information system collects performance data through the serial port of the sensor attached to the machine-parts manufacturing machine, analyzes these data and display them in the GUI fashion, and immediately reflects them in production planning. And also it develops production management system based on XML by using XML technology.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.4
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• pp.46-58
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• 2008

Naval combat management system is a kind of complex weapon systems performing naval ship's warfare mission by integrating various types of system including sensor systems, weapon systems and many kinds of communication system. Recently, there are many studies to apply commercial high-level communication middleware to naval combat system development to integrate and interoperate various kinds of heterogeneous on-board systems efficiently. An initial discovery mechanism is required for application modules to start communication with their relevant modules to apply middlware technology in developing naval combat system, which is characterized by large-scale, complex and real-time system. This paper suggests a fast hybrid discovery mechanism which combines static and dynamic discovery mechanism and confirms its adaptability by an experiment on testing environment.

• Journal of Platform Technology
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• v.6 no.4
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• pp.78-86
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• 2018

In this paper, a VR-based cyber hiking system was designed to provide virtual reality for famous mountains that can offer the real senses and feelings of hiking in supporting environmental factors of actual mountains such as the temperature, air, sound, echoes, etc., of the mountain the user wants to climb. The VR-based cyber hiking system that reflects real-time site conditions is largely consisted of the data collection module that collects data from the live site, multiple drive modules that enables the user to feel real senses using data from the sites, and sensor module to detect the stimuli provided by the drive modules and the user's physical body transition. Unlike existing VR-based hiking systems, the proposed cyber hiking system not only provides simple virtual reality for the wanted mountain, but can also provide the natural conditions of real mountains and implement the uphill and downhill of hiking routes. In particular, it has the effect of providing fun and game elements to users by excluding unnecessary conditions and risks that may arise in actual hiking and instead supporting augmented realities such as squirrels on actual hiking paths. In addition, in providing users with the changes in their body before and after hiking, it is expected to be effective in providing diverse feedback such as the height, gradient, and speed of mountain hiking.

• KIPS Transactions on Software and Data Engineering
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• v.8 no.4
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• pp.145-152
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• 2019

Unlike a single value from a sensor device, a massive data set has characteristics for various processing aspects; input data may be formed in a different format, the size of input data varies, and the processing time of analyzing input data is not predictable. Therefore, context aware systems may contain complex modules, and these modules can be implemented and used in different ways. In order to solve these problems, we propose a method to handle context information from the result of analyzing massive data. The proposed method considers analysis work as a different type of abstracting context and suggests the way of representing context information. In experiment, we demonstrate how the context processing engine works properly in a couple of steps with healthcare services.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.250-256
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• 2009

This paper presents a robotic tower-crane system using encoder and gyroscope sensors as path tracking devices. Tower crane work is often associated with falling accidents and industrial disasters. Such problems often incur a loss of time and money for the contractor. For this reason, many studies have been done on an automatic tower crane. As a part of 5-year 23-million-dollar research project in Korea, we are developing a robotic tower crane which aims to improve the safety level and productivity. We selected a luffing tower crane, which is commonly used in urban construction projects today, as a platform for the robotic tower crane system. This system comprises two modules: the automated path planning module and the path tracking module. The automated path planning system uses the 3D Cartesian coordinates. When the robotic tower crane lifts construction material, the algorithm creates a line, which represents a lifting path, in virtual space. This algorithm seeks and generates the best route to lift construction material while avoiding known obstacles from real construction site. The path tracking system detects the location of a lifted material in terms of the 3D coordinate values using various types of sensors including adopts encoder and gyroscope sensors. We are testing various sensors as a candidate for the path tracking device. This specific study focuses on how to employ encoder and gyroscope sensors in the robotic crane These sensors measure a movement and rotary motion of the robotic tower crane. Finally, the movement of the robotic tower crane is displayed in a virtual space that synthesizes the data from two modules: the automatically planned path and the tracked paths. We are currently field-testing the feasibility of the proposed system using an actual tower crane. In the next step, the robotic tower crane will be applied to actual construction sites with a following analysis of the crane's productivity in order to ascertain its economic efficiency.

• Journal of the Institute of Convergence Signal Processing
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• v.10 no.3
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• pp.207-213
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• 2009

The quality of tap water on the whole water-supply system, from a large filtration plant to a private faucet, has to be guaranteed the standards of drinking water. At this point in time, however, the supply process of the tap water has not been monitored and managed scientifically. The piped water, especially the most small-scale reservoirs(underground or overhead type) are always exposed to various contaminations and impurities. Recently monitoring systems of water-quality were spread on some large filtration plants or distributing reservoirs. In particular, the water quality monitoring method using the internet is adopted into some local government whose inhabitants can check up the water quality anytime and anywhere. The construction of this system that has to apply a large scale needs, and has a limitation on the small water-supply system, such as apartments, public facilities and small-scale underground or overhead reservoirs. In this work, we suggest the integration system of individual water-quality sensor modules that have a low price. By using the developed integration system and online monitoring program operated on the internet, the system managers of reservoirs can monitor and manage water-quality characteristic values of drinking water in online. Since the proposed system was modularized, the system can be applied easily into various reservoirs with a low cost and regardless of its scale, small or large.

• Journal of Information Technology Applications and Management
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• v.21 no.4
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• pp.203-223
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• 2014

This study proposes a novel context-aware recommender system, which is designed to recommend the items according to the customer's responses to the previously recommended item. In specific, our proposed system predicts the user's emotional state from his or her responses (such as facial expressions and movements) to the previous recommended item, and then it recommends the items that are similar to the previous one when his or her emotional state is estimated as positive. If the customer's emotional state on the previously recommended item is regarded as negative, the system recommends the items that have characteristics opposite to the previous item. Our proposed system consists of two sub modules-(1) emotion prediction module, and (2) responsive recommendation module. Emotion prediction module contains the emotion prediction model that predicts a customer's arousal level-a physiological and psychological state of being awake or reactive to stimuli-using the customer's reaction data including facial expressions and body movements, which can be measured using Microsoft's Kinect Sensor. Responsive recommendation module generates a recommendation list by using the results from the first module-emotion prediction module. If a customer shows a high level of arousal on the previously recommended item, the module recommends the items that are most similar to the previous item. Otherwise, it recommends the items that are most dissimilar to the previous one. In order to validate the performance and usefulness of the proposed recommender system, we conducted empirical validation. In total, 30 undergraduate students participated in the experiment. We used 100 trailers of Korean movies that had been released from 2009 to 2012 as the items for recommendation. For the experiment, we manually constructed Korean movie trailer DB which contains the fields such as release date, genre, director, writer, and actors. In order to check if the recommendation using customers' responses outperforms the recommendation using their demographic information, we compared them. The performance of the recommendation was measured using two metrics-satisfaction and arousal levels. Experimental results showed that the recommendation using customers' responses (i.e. our proposed system) outperformed the recommendation using their demographic information with statistical significance.

• Journal of Korea Multimedia Society
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• v.10 no.10
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• pp.1260-1270
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• 2007

Testing and diagnosis of analog circuits(or mixed-signal circuits) continue to be a hard task for test engineers and efficient test methodologies to solve these problems are needed. This paper proposes a novel analog circuits test technique using time slot specification (TSS) based built-in current sensors (BICS). A technique for location of a fault site and separation of fault type based on TSS is also presented. The proposed built-in current sensors and TSS technique has high testability, fault coverage and a capability to diagnose catastrophic faults and parametric faults in analog circuits. In order to reduce time complexity of test point insertion procedure, external output and power nodes are used for test points and the current sensors are implemented in the automatic test equipment(ATE). The digital output of BICS can be easily combined with built-in digital test modules for analog IC test.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.6
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• pp.1405-1410
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• 2015

In this study we designed the radiation-hardened sensor signal processing modules that can be commonly used for a variety of sensors during normal operation and even in high-radiation environments caused by an accident. First development module was designed to receive the change of the R and C value from the sensors and to process the signal as a PWM modulation scheme. This module was assessed to have ± 10% error to the Full-Scale in the radiation test in the range of 12 kGy TID. The main cause of the error was analyzed as the annealing of the common circuit in the switching element and the consequent increase in the duty ratio of the pulse width modulation circuit according to the radiation dose increasement. The redesigned module for higher radiation resistivity with Stub transistor circuit was found to have less than 5% error to the Full-scale from the radiation test results for 20.7 kGy TID range.