• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.2C
• /
• pp.150-159
• /
• 2007

In Part 1 of this paper, the test statistics are obtained for detecting weak known signals in observations corrupted by multiplicative and first-order Markov additive noise. In this second part, the asymptotic and finite sample-size performance of several detectors are obtained and compared based on the test statistics. From the performance comparisons, it is confirmed that the dependence among interference components need to be taken into account to maintain the detection performance.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2010.04a
• /
• pp.566-569
• /
• 2010

레이저 포인터를 검출하는 과정은 포인터의 위치를 검출하는 과정과 입력된 레이저 포인터의 좌표를 모니터의 좌표로 변환하는 과정으로 나눌 수 있다. 레이저 포인터의 추적에 있어서 다변하는 환경의 영향으로 강건성의 확보가 어렵다. 기존의 추적 방식인 Mean-Shift 알고리즘의 경우에는 계산량이 많아서 실시간으로 입력되는 동영상에는 부적합하다. 반면에 CamShift 알고리즘은 빠른 수행이 가능하여 비디오 영상 및 실시간 영상에 적용하기에 적합하고 배경 변화의 영향을 적게 받는다. 또한 검출하려는 색과 같은 색에 의해서 간섭 받는 현상을 방지할 수 있다. 배경이 복잡한 형태이거나 배경이 동적으로 움직일 때에도 강건한 결과를 얻을 수 있다. 제안된 알고리즘을 실환경에 적용한 결과 검출하고자 하는 물체가 예측 영역을 넘나들거나 또는 화면으로부터 지나치게 멀어지거나 가까워져서 상대적인 크기가 변화할 수 있는 불확실한 변화에도 안정적으로 반응함을 알 수 있었다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.41 no.5
• /
• pp.531-538
• /
• 2016

In this paper, we have proposed MIMO-IBFD system that can transmit and receive multiple data stream at the same time in the single band, and analyze the system. We have confirmed that MIMO-IBFD system requires multiple RF cancellation and multiple Digital cancellation techniques. In simulation, we have analyzed characteristic of received signal on MIMO-IBFD system, and evaluate system performance of conventional $2{\times}2$ MIMO system and MIMO-IBFD system. As simulation results, we have confirmed that MIMO-IBFD system can transmit and receive multiple data stream at the same time in the single band by using multiple RF and digital cancellation techniques. Additionally, we have confirmed that BER performance of $2{\times}2$ MIMO-IBFD system with low-level QAM modulation is similar to performance of $2{\times}2$ MIMO system, and BER performance of $2{\times}2$ MIMO-IBFD system with high-level QAM modulation is degraded in comparison with $2{\times}2$ MIMO system with high-level QAM modulation. We can confirm that MIMO-IBFD system requires high level self-interference cancellation technique in order to use high level modulation.

• The Journal of the Acoustical Society of Korea
• /
• v.28 no.4
• /
• pp.318-327
• /
• 2009

In this paper, we propose a 3-D geometric localization method for near-field broadband source in shallow water environments. According to the waveguide invariant theory, slope of the interference pattern which is seen in a sensor spectrogram directly proportional to a range of the source. The relative ratio of the range between source and sensors was estimated by matching of two interference patterns in spectrogram. Then this ratio is applied to the Apollonius's circle which shows the locus of a source whose range ratio from two sensors is constant. Two Apollonius's circles from three sensors make the intersection point that means the horizontal range and the azimuth angle of the source. And this intersection point is constant with source depth. Therefore the source depth can be estimated using 3-D hyperboloid equation whose range difference from two sensors is constant. To evaluate a performance of the proposed localization algorithm, simulation is performed using acoustic propagation program and analysis of localization error is demonstrated. From simulation results, error estimate for range and depth is described within 50 m and 15 m respectively.

• Korean Journal of Environment and Ecology
• /
• v.16 no.4
• /
• pp.457-464
• /
• 2003

A valley forest in Sangbuun area at Jirisan National Park was studied to investigate forest structure in relation to altitude and part of the slope. Forty-eight quadrats were set up in the valley forest along altitude of 726m to 1,090m and part of the slope, and vegetation analysis for the woody species in the tree and subtree layers were carried out. With increasing elevation belt, mean DBH, height and basal area of the trees in the tree layer increased while their density decreased. This trends may be caused by the disturbance which was relatively severe in the low elevation area. As elevation increased, the importance percentages of Fraxinus rhynchophylla, Quercus variabilis and Quercus mongolica increased while those of Styyax japonicus, Carpinus laxiflora and Pinus densiflora decreased. The importance percentages of Quercus variabilis and Pinus densiflora increased as going from lower part to upper part of the slope. However, the opposite trend was found for the importance percentages of Acer mono and Corlus heterophylla var. thunbergii. Number of species and species diversity decreased as increasing elevation and going from lower part to upper part of the slope. According to importance percentage and cluster analysis, the valley forest was classified into three forest communities of Quercus serrata-broad-leaved tree species community in lower part of the slope at low elevation belt, middle elevation belt and middle and upper parts of the slope at high elevation belt, Pinus dnsiflora-Quercus serrata community in middle and upper parts at low elevation belt, and Quercus mongolica-broad-leaved tree species community in lower part of the slope at high elevation belt and top area.

• Analytical Science and Technology
• /
• v.13 no.6
• /
• pp.781-788
• /
• 2000

Tellurium in simulated nuclear spent fuels (SIMFUEL) has been determined by hydride generation-inductively coupled plasma atomic emission spectrometry (HG-ICP-AES). Parameters such as concentrations of HCl and $NaBH_4$, flow rate of HCl and $NaBH_4$ were optimized and then the effects of U, Mo, Pd, Rh and Ru on the Te intensity were investigated. A thiourea as a masking agent was used to eliminate or minimize such interferences specially caused by palladium. Tellurium was measured by HG-ICP-AES and ICP-MS after separation of tellurium from SIMFUEL with cation exchange chromatography. The relative deviation between direct measurement and separation method was less than 6% based on the data by ICP-MS.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.5C
• /
• pp.398-405
• /
• 2005

The multiuser detection (MUD) based wireless receiver requires more accurate channel estimation than the single user detection (SUD) schemes such as Rake receiver, and hence the post processing is required for MUD to clean up the estimated channel coefficients by eliminating the noise only coefficients. The adaptive post processing method is proposed in order to provide more accurate channel responses and the power level of the background noise and interferences at the cost of the negligible processing delay compared to the conventional method based on the threshold test with the threshold value relative to the noise variance. The simulations are performed in 3GPP-TDD mode environment. The results show that the noise estimation error of the proposed method is maximum $10\%$, which is much smaller than $50\%$ maximum error of the conventional method.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.41 no.2
• /
• pp.1-8
• /
• 2004

This paper describes the design of monolithic optical transceiver circuitry being used as a part of the fiber optic modules. It has been designed in 0.6 ${\mu}{\textrm}{m}$ 2-poly 3 metal silicon CMOS analog technology and operates at 155.52 Mbps(STM-1) data rates. It drives laser diode to transmit intensity modulated optical signal according to 155.52 Mbps electrical data from system. Also, it receives 155.52 Mbps optical data that transmitted from other systems and converts it to electrical data using photo diode and amplifier. To avoid noise and interference between transmitter and receiver on one chip, layout techniques such as special placement, power supply separation, guard ring, and protection wall were used in the design. The die area is 4 ${\times}$ 4 $\textrm{mm}^2$ and the estimated power dissipation is less than 900 ㎽ with a single 5 V supply.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.41 no.9
• /
• pp.11-17
• /
• 2004

This paper describes the implementation of monolithic optical transceiver circuitry being used as a part of the fiber optic modules. It has been fabricated in 0.6 ${\mu}{\textrm}{m}$ 2-poly 3-metal silicon CMOS analog technology and operates at 155.52 Mbps(STM-1) data rates. It drives laser diode to transmit intensity modulated optical signal according to 155.52 Mbps electrical data from system. Also, it receives 155.52 Mbps optical data that transmitted from other systems and converts it to electrical data using photo diode and amplifier. To avoid noise and interference between transmitter and receiver on one chip, layout techniques such as special placement, power supply separation, guard ring, and protection wall were used in the design. The die area is 4 ${\times}$ 4 $\textrm{mm}^2$, and it has 32.3 ps rms and 335.9 ps peak to peak jitter on loopback testing. the measured power dissipation of whole chip is 1.15 W(230 mW) with a single 5 V supply.

• Korean Journal of Optics and Photonics
• /
• v.28 no.4
• /
• pp.146-152
• /
• 2017

Alignment of the mirrors composing a space telescope is an important process for obtaining high optical resolution and performance of the camera system. The alignment of mirrors using cube mirrors requires a relative coordinate mapping between the mirror and the cube mirror before optical-system integration. Therefore, to align the spacecraft camera mirrors, the relative coordinates of the vertex of each mirror and the corresponding cube mirror must be accurately measured. This paper proposes a new method for finding the vertex position of a primary mirror, by using an optical fiber and alignment segments of a computer-generated hologram (CGH). The measurement system is composed of an optical testing interferometer and a multimode optical fiber. We used two theodolites to measure the relative coordinates of the optical fiber located at the mirror vertex with respect to the cube mirror, and achieved a measurement precision of better than $25{\mu}m$.