• Journal of Biomedical Engineering Research
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• v.42 no.6
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• pp.259-267
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• 2021

Recently, the market for personal health care and medical devices based on Bluetooth Low Energy(BLE) has grown rapidly. BLE is being used in various medical data communication devices based on low power consumption and universal compatibility. However, since data errors occurring in the transmission of medical data can lead to medical accidents, it is necessary to analyze the causes of errors and study methods to reduce data error. In this paper, the minimum communication speed to be used in medical devices was set to at least 800 byte/sec based on the wireless electrocardiography regulations of the Ministry of Food and Drug Safety. And the data loss rate was tested when data was transmitted at a speed higher than 800 byte/sec. The factors that cause communication data error were classified, and the relationship between each factor and the data error rate was analyzed through experiments. When there were two or more activated peripherals connected to the central, data error occurred due to channel hopping and bottleneck, and the data error rate increased in proportion to the communication distance and the number of activated peripherals. Through this experiment, when the BLE is used in a medical device that intermittently transmits biosignal data, the risk of a medical accident is predicted to be low if the number of peripherals is 3 or less. But, it was determined that BLE would not be suitable for the development of a biosignal measuring device that must be continuously transmitted in real time, such as an electrocardiogram.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.3
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• pp.754-766
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• 2010

In the wireless communication protocols, a network device is responsible for the operation of lower-layers. The network device consists of hardware and software modules, so it can be designed using system-on-chip simulator. The simulator design needs the support of a network simulator as well as system-on-chip simulator, because the network device interact with various higher layer communication protocols. Therefore the co-simulator can become a development environment of the network device through the combining of them. In this paper we propose a co-simulator combining these two simulators. The proposed co-simulator does not degrade performance due to integrations. Also, it is easy to integrate them because the implementation of the kernel is independent.

• Journal of Electrical Engineering and Technology
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• v.8 no.6
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• pp.1559-1570
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• 2013

The family of ISO/IEEE11073 standards is the basis of the e-health system and provides interoperability for personal health devices. In the early stage of e-health business, it was expected that people would use a health device individually. In this case, a measurement datum was episodically acquired and generally transmitted for one person at a time. Recently, a health device is expected to be used by multiple people, and large amounts of measurement data are gathered in a short time interval. In addition, mobile health devices have become more popular, so that energy efficient measurement data transmission is required, to prolong the use of a device. In IEEE11073 PHD standards, data transmission is classified into three different types: immediate individual transfer, small block transfer, and large block transfer. The large block transfer using PM-store concept provides efficient transmission. However, an existing PM-store has problem when a device is used by multiple people. To address the defined problem, a modified PM-segment that is in compliance with 11073 standards is proposed in this paper. In particular, the proposed PM-segment is designed to minimize the additional complexity of an agent instead of a manager and it is interoperable with the existing manager. The proposed PM-segment shows better performance than the existing PM-segment, in terms of memory requirements and expected queue time. Also, performance comparison among the three transfers is performed in regard to the delay time and communication power consumption points of view.

• Korean Journal of Computational Design and Engineering
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• v.19 no.2
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• pp.157-168
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• 2014

In this paper, HSE (Health and Safety Environments) research with smart device and biometrics is conducted for the worker's HSE enhancement in the manufacturing shop floor. Today, various kinds of smart devices are popularized extensively. In addition, the wearable type devices are being introduced such as google glass very recently. Smart device of werable type is exptected to bring great opportunity out in terms of HSE functionality. Smart devices of phone or tablet type are being used for on-line work between control center and manufacturing shop floor by virtue of wireless communication. However, those devices are not appropriate for detecting of worker's physical senses such as temperature and pulse. In this paper, we developed a glass type smart device and required funictions for HSE enhancement with the investigation of biometrics technology. Also, required sensors are investigated for the detecting of temperature, pulse and noxious gasses. Smart device of glass type has advantages in that most senses of personnel are gathered around faces, and also it's possible to detect neutral axis of body because the wearing location is fixed. We expect that the proposing HSE product of glass type smart device could contribute the enhancement of the HSE of manufacturing shop floor.

• Journal of Korea Multimedia Society
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• v.17 no.12
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• pp.1473-1483
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• 2014

A public restroom is different from a household toilet in terms of location and a large number of sharing users. In addition, public restroom is usually messy and filthy. Recently, public toilet tends to be clearly managed than before, but it still has hygienic and clear problems. In this paper, we propose a machine-to-machine (M2M)-based public restroom management system to solve these problems, in which the system with a wireless communication device sends the status information of the toilet, such as blockage or trouble detected by a sensor, to the manager of the restroom at a remote location. In particular, we have developed a prototype management system for public restroom taking into account several system requirements, and verified the basic operations and performance of the management system. With the application of the system to public facilities, it will furnish users with more pleasant environments by restroom administrators who can respond effectively to the troubled toilet.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.6
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• pp.85-92
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• 2000

This paper has developed the system that can monitor the distribution transformers(pole and pad) using simplified deterioration detecting sensor in oil and wireless data communication. This system is made up by deterioration detecting sensor, oil level measuring system, deterioration measuring system and communication unit. To prove the usefulness of the system, the paper compared and analyzed the system with the existed system, and after studying the correlation of the both, the result proved goodness of the new system. The proposed monitoring system, when it is used on the pole and pad transformer, would make the reliable diagnoses possible with less rate.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2B
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• pp.289-298
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• 2004

Recently, mobile commerce is widely spread around the world according to fast growth of the mobile communication market. The existing digital document is not well fit in mobile commerce because of weakness of the hardware of mobile devices, low bandwidth of wireless communication, and the constraints of the size and resolution of the display. In this paper, we analyzed the elements of the digital document proper for mobile commerce based on wireless communication, designed the XML form for the digital document, and implemented the X-Auth which is an authoring tool for the XML digital document. X-Auth does not require that the author or user know XML. And also it makes it possible to create the digital document fit for the size of the mobile device display and therefore remove inconvenience due to the scrolls.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.12
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• pp.164-175
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• 2008

Atmospheric effects on laser beam propagation can be broken down into two categories: attenuation of the laser power and fluctuation of laser power due to laser beam deformation. Attenuation consists of scattering of the laser light photons by the fog. Laser beam deformation occurs because of small-scale dynamic changes in the index of refraction of the atmosphere. This causes pointing error. In order to analyse these effect on optical wireless communication system, in this paper uses cassegrain optics as a transmitting and receiving telescope, AID as a detecting device and ill as a light source. The signal modulating and demodulating method is a IM/DD. I show the effects of fog and pointing error and calculate the possible communication distance for BER is $10^{-9}$.

• Journal of the Korea Society for Simulation
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• v.20 no.3
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• pp.41-48
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• 2011

Wireless communication technology developed, portable wireless devices based on wireless network including the smartphone rapidly developed, and products with functions similar to highly efficient computer are being launched. Therefore, active studies to enable performance of works, which were previously held in computers, on portable wireless terminal are being held. Until now, simulation was undertaken using computers which satisfy high performance computing resource. Such contains a problem that it cannot break away the limit of space. Portable wireless terminal has the merit that it can break away from the limit of space by using wireless network in comparison to wired environment. In this paper, it suggests a simulator based on wireless devices for distributed simulation. For such purpose, the performance time of simulation will be compared in regards to the case of performing nodes control simulation in a single highly efficient computer and the case of performing distributed simulation in many wired and wireless network environments. Through the comparison, the possibility for utility of portable wireless terminal as the object of distributed simulation will be verified, and it will be presented that simulation can be performed in a shorter time by performing distributed simulation under various wired and wireless network environments away from the limit of space.

• Journal of Information Technology Services
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• v.16 no.4
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• pp.223-234
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• 2017

The audible pedestrian signal (APS) is an add-on device which connects to the pedestrian signaling device and informs the contents and changes of the signaling by sound. It provides walking direction information of the pedestrian crossing so that the blind people can safely cross the pedestrian crossing. In an intersection where a plurality of audible pedestrian signal (APS) are installed at an intersection crosswalk, existing audible pedestrian signal (APS) operate simultaneously in the communication radius of a wireless remote controller, which may cause confusion for the blind people and the public may complain about the noise. In this paper, we developed a BLE (Bluetooth Low Energy)-based audible pedestrian signal (APS) system capable of supporting two-way communications with a smart-phone that can cross the intersection safely and improve the walking comfort and traffic safety for the blind people. The proposed method is a method in which the BLE beacon communication based audible pedestrian signal (APS) presents active service to the blind people, and the existing audible pedestrian signal (APS) is a way of requesting the passive service by the blind people with the wireless remote control by the unidirectional communication based on 358Mhz. The developed system is installed in the crossroad of Doma-dong, Seo-gu, Daejeon, and it is tested and operated by the blind people. The satisfaction evaluation and analysis of the audible pedestrian signal (APS) for the blind people have good results and are planned to be expanded in the future.