• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.5
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• pp.1503-1515
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• 2023

This paper considers the jointly active and passive beamforming design in the IRS-aided MISO downlink vehicle communication system where both V2I and V2V communication paradigms coexist. We formulate the problem as an optimization problem aiming to minimize the total transmit power of the base station subject to SINR requirements of both V2I and V2V users, total transmit power of base station and IRS's phase shift constraints. To deal with this non-convex problem, we propose a method which can alternately optimize the active beamforming at the base station and the passive beamforming at the IRS. By using first-order Taylor expansion, matrix analysis theory and penalized convex-concave process method, the non-convex optimization problem with coupled variables is converted into two decoupled convex sub-problems. The simulation results show that the proposed alternate optimization algorithm can significantly decrease the total transmit power of the vehicle base station.

• Journal of Astronomy and Space Sciences
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• v.18 no.1
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• pp.7-14
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• 2001

Red giant branch shape and the luminosity of horizontal branch on the (V-I)-V CMD are used to derive the metallicity the globular cluster NGC 5053. The metallicities of NGC 5053 derived by SMR method ([Fe/H]=-2.62$\pm$0.07) and the relation between[Fe/H] and $(V-I)_{0.g}$ ([Fe/H]=-2.50) are in good agreement with previously determined values. This result confirms that the morphologies of RGB and HB on the (V-I)-V CMDs can be good indirect photometric metallicity indicators of galactic globular clusters.

• Journal of IKEEE
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• v.11 no.1 s.20
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• pp.54-60
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• 2007

In this study novel ESD protection device, namely, N/P-type Low Voltage Triggered SCR, has been proposed, for high speed I/O interface. Proposed device could lower high trigger voltage($\sim$20V) of conventional SCR and reduce latch-up phenomenon of protection device during the normal condition. In this Study, the proposed NPLVTSCR has been simulated using TMA MEDICI device simulator for electrical characteristic. Also the proposed device's test pattern was fabricated using 90nm TSMC's CMOS process and was measured electrical characteristic and robustness. In the result, NPLVTSCR has 3.2V $\sim$ 7.5V trigger voltage and 2.3V $\sim$ 3.2V holding voltage by changing PMOS gate length and it has about 2kV, 7.5A HBM ESD robustness(IEC61000-4-2).

• Journal of the Korean Chemical Society
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• v.30 no.1
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• pp.19-26
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• 1986

A titanium oxide thin films were prepared by air oxidation and vapour oxidation and a $TiO_2$ single crystal was reduced by heating in an argon atmosphere. All the electrode characteristics of the Ti$O_{2-x}$, thin films are not different from those of slightly reduced single crystal rutile. In cyclic voltammogram of oxygen containing electrolyte solution at Ti$O_{2-x}$ electrodes, cathodic peaks were observed at between -0.8V and -1.0V vs. SCE. The cathodic current near 0V vs. SCE in saturated solution with nitrogen was observed to be greater than in saturated solution with air. The chronoamperogram was represented by the equation of i = $i_0e^{-kt}$, when the rate constant k was represented by the equation of k =$k_0{[H^+]}^nexp(A{\eta}+E_a/RT)$ The values of activation energy $E_a $were found to be 4.6~4.8kcal/mole in overpotential range of 0.035∼0.145 V and 1.6kcal/mole in overpotential range of 0.2∼0.5V. The values of n and A were found to be 0. 1 and 5.4~5.6/V in range of 0.035~0.145V, and in range of 0.2~0.5V, to be 0.04 and 1.3/V, respectively. This can be interpreted as an totally irreversible reduction of oxygen.

• Journal of IKEEE
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• v.24 no.4
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• pp.1172-1175
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• 2020

Automotive ECU integrates CPU core, IVN controller, memory interface, sensor interface, I/O interface, and so on. Current automotive ECUs are often developed with proprietary processor architectures. However, demends for standard processors such as ARM and RISC-V increase rapidly for saftware compatibility in autonomous vehicles and connected cars. In this paper, an automotive ECU is designed for parking assist system based on RISC-V with open instruction set architecture. It includes 32b RISC-V CPU core, IVN controllers such as CAN and LIN, memory interfaces such as ROM and SRAM, and I/O interfaces such as SPI, UART, and I2C. Fabricated in 65nm CMOS technology, its operating frequency, area, and gate count are 50MHz, 0.37㎟, and 55,310 gates, respectively.

• Journal of IKEEE
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• v.20 no.3
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• pp.295-298
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• 2016

In this paper, we analysed the properties of the conventional ESD protection devices such as SCR, MVSCR, LVTSCR. The electrical characteristics and the turn-on time properties are simulated by Synopsys T-CAD simulator. As the results, the devices have the holding voltages between 2V and 3V, and the trigger voltage of about 20V with SCR, of about 12V with MVSCR, of about 9V with LVTSCR. The results of the simulation for the turn-on time properties are 2.8ns of SCR, 2.2ns of MVSCR, 2.0ns of LVTSCR. Thus, we prove that LVTSCR has the shortest turn-on time. However, the second breakdown currents(It2) of the devices are 7.7A of SCR, 5.5A of MVSCR, 4A of LVTSCR. This different properties have to be adapted by the operation voltages for I/O Clamps.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.211-215
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• 2015

It comes into the spotlight as the new Blue Ocean in which the connected car industry in which the car and mobile communication technology is convergence. All sorts of infortainments services connecting with the portable electronic device(Smart phone, tablet PC, and MP3 player) and car are rapidly grown. The Connected car emphasizes the vehicle connectivity with the concept that the car has communication with the around on a real time basis and it provides the safety and expedience to the operator and using the thing of Internet (IoT) in the car and supports the application, presently, the entertainment service including the real-time Navigation, parking assistant function, not only the remote vehicle control and management service but also Email, multimedia streaming service, SNS and with the platform. Intelligent vehicle network is studied as the kind according to MANET(Mobile Ad Hoc Network) for the safety operation of the cars of the road and improving the efficiency of the driving. The intelligent vehicle network is comprised for the driving information offering changing rapidly of the communication(V2V: Vehicle to Vehicle) between the car and the car, communication(V2I : Vehicle to Infrastructure) between the infrastructure and the car, and V2X (Vehicle to Nomadic).

• Journal of KIISE:Information Networking
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• v.35 no.4
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• pp.311-317
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• 2008

This paper proposes a session key exchange scheme for providing secure communication between Vehicles and Infrastructure in VANET. In the current VANET environment, IEEE 802.11i or PKI based mechanism is used to provide secure communication between V2I. However, since the vehicles and the frequent changes of network topology, VANET nodes have some difficulties to exchange the session key using IEEE 802.11i or PKI method. In the proposed scheme, Local Router is newly defined for exchanging the session key between moving vehicles and infrastructure. A session key is generated by XOR operation based on the random values between Local Router and OBU. As a result, the proposed scheme has a noticeable advantage on the fastness of key exchange by exchanging session keys between LR and OBU.

• Journal of applied mathematics & informatics
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• v.24 no.1_2
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• pp.261-271
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• 2007

The symbol C($m_1^{n_1}m_2^{n_2}{\cdots}m_s^{n_s}$) denotes a 2-regular graph consisting of $n_i$ cycles of length $m_i,\;i=1,\;2,\;{\cdots},\;s$. In this paper, we give some construction methods of cyclic($K_v$, G)-designs, and prove that there exists a cyclic($K_v$, G)-design when $G=C((4m_1)^{n_1}(4m_2)^{n_2}{\cdots}(4m_s)^{n_s}\;and\;v{\equiv}1(mod\;2|G|)$.

• Korean Journal of Veterinary Research
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• v.33 no.4
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• pp.719-734
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• 1993

The electrocardiographic(ECG) parameters on the standard limb leads in the normal Korean native cattle have been measured with a 3 channel Electrocardiograph built in a computed analysis. The study was conducted on the animals 98 heads of mean age of 17.7 months. Conduction parameters, waves, intervals and segments have been recorded. The recordings were analyzed as to shape and amplitude of the P and T waves and the components of the QRS complex. Heart rate was recorded by the Electrocardiogram which were a mean of $80.4{\pm}11.6beats/min$. And the younger had a higher heart rate than the older one. Average conduction times in the RP, the QRS complex and the QTc interval recorded $166.7{\pm}23.1msec.$, $79.7{\pm}8.8msec.$ and $395.5{\pm}30.4msec.$, in the P and T wave duration recorded $70.1{\pm}13.5msec.$ and $97.6{\pm}16.9msec.$, and in the PR and ST segment duration recorded $97.9{\pm}23.5msec.$ and $173.9{\pm}40.3msec.$, respectively. The wave forms in each lead observed various types. The amplitudes of wave type showed the highest frequency in each lead that were analyzed as follow : 1. In P wave, amplitudes of the positive type showed the frequency of 65.3%, 82.7% and 52.0% in leads I, II and III that were $103.1{\pm}47.8{\mu}V$, $115.2{\pm}37.3{\mu}V$ and $67.4{\pm}26.9{\mu}V$, and it showed the frequency of 54.1% and 85.7% in the leads aVL and aVF that were $63.7{\pm}23.0{\mu}V$, $88.0{\pm}83.6{\mu}V$, respectively. Average amplitude of the negative type showed the frequency of 78.6% in lead aVR which was $99.3{\pm}38.0{\mu}V$. 2. Average amplitude of the QRS complex were from $362.8{\pm}177.7{\mu}V$ to $532.8{\pm}253.9{\mu}V$(mean of $449.1{\pm}57.2{\mu}V$) that in all leads except lead I were manifested the Low-Voltage QRS complex(below 0.5mV). Average amplitudes of each wave type in the QRS complex aere $-50.2.4{\pm}258.2{\mu}V$ and $-428.6{\pm}195.1{\mu}V$ in the QS groups type that showed a frequency of 66.3%, 70.4% in the leads I and aVL, were $451.1{\pm}20.4.0{\mu}V$, $387.6{\pm}175.8{\mu}V$ and $299.3{\pm}146.5{\mu}V$ in the R groups type that showed a frequency of 48.0%, 53.1% and 34.7% in the leads III, aVR and aVF, and were $-307.5{\pm}180.3{\mu}V$, $201.4{\pm}77.2{\mu}V$ in the QR wave type which showed a frequency of 39.8% in lead II, respectively. 3. In T wave, amplitude of the positive type showed the frequency of 50.0%, 82.7%, 51.0% and 57.1% in leads II, III aVR and aVF which were $214.9{\pm}115.6{\mu}V$, $188.5{\pm}119.3{\mu}V$, $191.0{\pm}93.7{\mu}V$ and $165.7{\pm}91.9{\mu}V$, and the negative type showed a frequecny of 66.3% and 72.5% in leads I and aVL. that were $221.3{\pm}112.5{\mu}V$, $-173.6{\pm}86.7{\mu}V$, respectively. 4. Amplitude of ST segment in leads I, II and III were a mean of $-12.2{\pm}37.2{\mu}V$, $17.5{\pm}42.6{\mu}V$ and $28.3{\pm}40.4{\mu}V$, in leads aVR, aVL and aVF were $-3.9{\pm}32.5{\mu}V$, $-15.9{\pm}35.6{\mu}V$ and $26.2{\pm}37.5{\mu}V$, respectively.