• Journal of the Korea Society for Simulation
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• v.17 no.4
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• pp.199-208
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• 2008

Lately, since Complementary Metal Oxide Semiconductor(CMOS) image sensor system has low power, low cost and been miniaturized, hardware and applied software studies using these strengths are being carrying on actively. However, the products equipped with CMOS image sensor based polling method yet has several problems in degree of completeness of applied software and firmware, compared with hardware’s. CMOS image sensor system has an ineffective synchronous problem due to superfluous message exchange. Also when a sending of data is delayed continually, overhead of re-sending is large. So because of these, it has a problem in structural stability according to Polling Method. In this study, polling cycle was subdivided in high-speed synchronization method of firmware -based through MCU and synchronization method of Stepwise was proposed. Also, re-connection and data sending were advanced more efficiently by using interrupt way. In conclusion, the proposed method showed more than 20 times better performance in synchronization time and error connection. Also, a board was created by using C328R board of CMOS image sensor-based and ATmega128L which has low power, MCU and camera modules of proposed firmware were compared with provided software and analyzed in synchronization time and error connection.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.49 no.1
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• pp.57-63
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• 2012

In this paper, a switch sizing method is proposed in order to prevent the cross-regulation in the TM type SIDO DC-DC buck converter. In TM type SIDO DC-DC buck converter, a DCM operation is required. In the DCM operation, the inductor peak current is larger than that in the CCM. Because of the larger inductor peak current and the added switch resistance, the voltage drop is increased, resulting in possible cross-regulation. To solve this problem, the switch resistance must be considered in sizing the switch. To simplify the calculation of the resistance, the inductor current was replaced by the average load current. Using the proposed method, TM type SIDO DC-DC buck converter for camera module was designed to provide two independent supply voltage(2.8 V and 1.8 V). The designed circuit was fabricated in a standard $0.35{\mu}m$ CMOS process. At a switching frequency of 1 MHz and a load current of 200 mA, a power effciency of 80.7% was achieved.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.319-325
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• 2008

In this paper, we develop the multi sensor system, to get the sufficient information of mobile robot's environment. Mobile robot user interface, based on multi sensor system, can choice a suitable sensor by low-cost multi sensors and then acquisition information from remote robot's workspace using auto sequencing user display function. This research of multi sensor system is consists of ultrasonic sensor, position sensing detector, and low-cost CMOS camera module.

• The Journal of the Korea Contents Association
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• v.13 no.1
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• pp.30-39
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• 2013

In recent years, with the development of devices to collect multimedia data such as small CMOS camera sensor and micro phone, studies on wireless multimedia sensor network technologies and their applications that extend the existing wireless sensor network technologies have been actively done. In such applications, various basic schemes such as the processing, storage, and transmission of multimedia data are required. Especially, a security for real world environments is essential. In this paper, in order to defend the sniffing attack in various hacking techniques, we propose a multipath routing scheme for physically avoiding the data transmission path from the risk factors. Our proposed scheme establishes the DEFCON of the sensor nodes that are geographically close to risk factors and the priorities according to the importance of the data. Our proposed scheme performs risk factor detour multipath routing through a safe path considering the DEFCON and data priority. Our experimental results show that although our proposed scheme takes the transmission delay time by about 5% over the existing scheme, it reduces the eavesdropping rate that can attack and intercept data by the risk factor by about 18%.