• Journal of Advanced Navigation Technology
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• v.14 no.4
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• pp.545-552
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• 2010

In this paper, we study on a radio multiple sensing interface module to accurately decide serious error sources that are happened by unexpectable problems in industrial fields, in addition, we study a reliability improvement scheme to guarantee the integrity of multiple sensing data. For multiple sensing interface module, communication drivers such as USART, TWI, ADC and GPIO-I2C are implemented. to improve the transmission reliability, reed-Solomon code is used. From the simulation result of this system in indoor environment, we confirm that the reliability of RS coded data is improved about 5 times than uncoded data. Moreover, we prove that multiple sensing interface module is suitable to diagnose error sources of industrial automaton equipment.

• Journal of KIISE:Information Networking
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• v.35 no.4
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• pp.326-336
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• 2008

Wireless sensor networks have been studied with two typical applications called event-driven and periodic monitoring. Although these applications have different core requirements, they have the same low latency requirement. However, main issue of the protocol in wireless sensor networks was focused on an energy efficiency, so it has not considered the latency problem. In this paper, we propose the RA-MAC, an energy efficient and low latency MAC protocol using a new channel access mechanism and the RTS Aggregation scheme for wireless sensor networks. Our simulation results show that the RA-MAC provides energy savings and latency reduction.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.07a
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• pp.18-20
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• 2015

In ports of Korea, the marine traffic flow is congested due to a large number of vessels coming in and going out. In order to improve the safety and efficiency of these vessels, South Korea is operating with a Vessel Traffic System, which is monitoring its waters 24-7. However despite these efforts of the VTS (Vessel Traffic System) officers, marine accidents are occurring in their assigned districts and it is made a danger situation every 20minute. On this paper, we listened to Busan VHF channel for 3days and applied to collision risk model. With collision risk model, We deducted a moment which advise or recommend to vessel. We suggested a collision risk model as VTSO support system.

• Journal of Sensor Science and Technology
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• v.10 no.3
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• pp.187-195
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• 2001

A wireless telemetry measurement system, using ISFETs, was developed for environmental monitoring applications, industrial processes, medical treatments and so on. This system is composed of the measurement part located at remote site and a personal computer(PC) which control whole instrument process. The measurement part transmits measured data to the PC by RF transceiver, and transmitted data are analyzed and handled in the PC. Proposed system utilizing time division multiplexing for the transmission of 3channel ISFET signal. The measurement part has an identification number(ID) so that the PC controls many measurement parts separately. Experiments were performed using pH-ISFETs, and the implemented system operates well within designed specification and accuracy of 0.1 pH.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.45 no.3
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• pp.165-176
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• 2009

The process of berthing/deberthing operations for entering/leaving vessels in Busan northern harbor was analyzed and evaluated by using an integrated VTS(vessel traffic service) system installed in the ship training center of Pukyong National University, Busan, Korea. The integrated VTS system used in this study was consisted of ARPA radar, ECDIS(electronic chart display and information system), backup(recording) system, CCTV(closed-circuit television) camera system, gyro-compass, differential GPS receiver, anemometer, AIS(automatic identification system), VHF(very high frequency) communication system, etc. The network of these systems was designed to communicate with each other automatically and to exchange the critical information about the course, speed, position and intended routes of other traffic vessels in the navigational channel and Busan northern harbor. To evaluate quantitatively the overall dynamic situation such as maneuvering motions for target vessel and its tugboats while in transit to and from the berth structure inside a harbor, all traffic information in Busan northern harbor was automatically acquired, displayed, evaluated and recorded. The results obtained in this study suggest that the real-time tracking information of traffic vessels acquired by using an integrated VTS system can be used as a useful reference data in evaluating and analyzing exactly the dynamic situation such as the collision between ship and berth structure, in the process of berthing/deberthing operations for entering/leaving vessels in the confined waters and harbor.

• Atmosphere
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• v.12 no.4
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• pp.69-90
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• 2002

The infrared and microwave satellite observations have been used to derive the information of hydrometeors (i.e., cloud and precipitation) and atmospheric temperature. The observations were made by the Nimbus-4 Infrared Interferometer Spectrometer (IRIS) in 1970, and by the Microwave Sounding Unit (MSU) during the period 1980-99, which had channel 1~4 (Chl~4). The IRIS, which has a field of view of ~100 km, has been utilized to examine the cirrus and marine stratus clouds. The cirrus and stratus distributions were obtained, respectively, based on the spectral difference in the infrared window region, and the absorption of water vapor and $CO_2$ in the spectral region $870-980cm^{-1}$. The MSU Ch1 data has been used for low tropospheric temperature and hydrometeors, while the Ch2, Ch3 and Ch4, respectively, for the thermal state of midtroposphere, tropopause, and lower stratosphere. The climatic aspects of El Ni$\tilde{n}$o, Quasi-Biennial Oscillation (QBO) and temperature trends over the globe are discussed with the MSU data. This study suggests that the IRIS and MSU data are useful for monitoring the hydrometeors and atmospheric thermal state in climate system.

• Ocean and Polar Research
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• v.26 no.4
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• pp.595-606
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• 2004

Hydrographic survey in the Korea Strait has long history that has begun in August 1917 at the Busan - Tsushima cross section, still continues to date. However, chemical properties of bottom cold water found exclusively in the western channel of the Korea Strait during summer did not receive much scientific attention. The aim of the study is to decipher the enigmatic origin of the Korea Strait Bottom Cold Water (KSBCW) in terms of chemical properties. The physicochemical properties of the KSBCW are extracted from the CREAHS II hydrographic data. OMP method was applied to analyze origin of the KSBCW quantitatively. The KSBCW is well defined by low temperature below $10^{\circ}C$. The cold waters exhibited the local presence near the coast at about 120m depth with a thickness of 20m to 30m. The cold water was characterized by relatively cold, saline and higher chemical concentrations than adjacent waters. The KSBCW seems to have different origin kom that of the coastal upwelled waters at the Ulgi-Gampo because it is saline, denser and contains considerably less dissolved oxygen than upwelled waters. The physicochemical properties are reported to have noticeable annual variations which suggest the complex origin of the KSBCW. OMP analysis show that the KSBCW is a mixture of three water types; TMW (24%), ESIW (36%) and ESPW (40%). Relationship between the KSBCW and the east Sea circulation is traced by mapping the water masses that have similar T, S and DO of KSBCW. The result showed that the KSBCW is most possibly an extension of southward flowing coastal intermediate waters. Front these results, we expect that the monitoring KSBCW will provide us valuable information about the East Sea circulation.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.12
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• pp.933-937
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• 2009

This paper proposes a dynamic timeout scheduling for energy efficient and accurate aggregation by analyzing the single hop delay in wireless sensor networks based on IEEE 802.15.4. The proposed scheme dynamically configures the timeout value depending on both the number of nodes sharing a channel and the type of wireless media, with considering the results of delay analysis of the single hop delay. The timeout of proposed scheme is much smaller than the maximum single hop delay which is used as the timeout of traditional data aggregation schemes. Therefore the proposed scheme considerably reduces the energy consumption of idle monitoring for waiting messages. Also, the proposed scheme maintains the data accuracy by guaranteeing the reception ratio required by the sensor network applications. Extensive simulation has revealed that proposed scheme enhances energy consumption by 30% with maintaining data accuracy, as compared with the TAG data aggregation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.6
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• pp.2196-2201
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• 2010

The video transmission system using OFDM method at 18GHz frequency band was developed for wireless video transmission from subway to monitoring center when subway running. It is composed of digital modulation board and RF board. And it has a robust characteristics of multipath fading in subway tunnels at 18GHz. To verify the system, we used spectrum analyzer for analysing the output of transmission system and get the results that it has 350MHz frequency, 8MHz bandwidth and -19dBm channel power. Also we tested video receiving using MPEG-2 encoder and got good quality images.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.8
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• pp.9-16
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• 2007

Currently, the measurement of RF parameters for a base station in operation is typically limited to easily measured forward path items. In this paper, the forward monitoring ports of base stations are used to measure the reverse RF performance. The system has been implemented and effectiveness has been proven on an operating base station. The receiver sensitivity is measured using an internal CDMA modem which is used to monitor the output power based on closed loop power control when the modem is connected to the base station via a voice call. In order to improve accuracy, in addition to the modem Tx adjust(TxAdj) parameter, the detector's actual measurement is used. For accurate receiver sensitivity, the measurement should be made when there is no traffic which is not possible on an operating base station. Therefore, pilot channel chip energy to received signal power spectral density ratio$(E_c/I_o)$ compensation method is used to offset the receiver sensitivity degradation with voice traffic increase.