• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.3
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• pp.201-210
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• 1996

In this paper, we analyzed performance of a symbol timing recovery scheme for 16QAM Radio system. As a symbol timing recovery scheme, both maximum amplitude method(MAM) and wave difference method(WDM) are analyzed employing a pulse shaping filter, such as raised cosine filter(RCF) and nonlinear filter(NLF). Simulation result shows that the jitter performance of MAM or WDM using NLF is better than that using square root RCF. In order to estimate and compensate for the Rayleigh fading PSAM(Pilot Symbol Assisted Modulation) and space diversity are also employed. Consequently, BER performance of about $10^{-4}$ is obtained for $E_b/N_o$= 20 dB.

• Journal of Digital Convergence
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• v.20 no.4
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• pp.689-697
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• 2022

The purpose of this study is to analyze the difference before and after and the influencing factors health status according to the change in the timing of joined in the healthy city area, centering on the metropolitan area. The subjects of this study were divided into two areas. Using the Seoul Survey on Household Members, difference tests and multiple regression analyses were conducted to analyze differences according to timing changes and influencing factors on health status as of 2020. The difference in variables between regions 4 to 5 years and 1 year after joining the healthy city was different, and the factors affecting their health status were also different between regions 4 to 5 years after joining and regions 1 year after joining, so it is necessary to implement policies in consideration.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.223-224
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• 2007

To develop nuclear measurement system with characteristics including both re-configuration and multi-functions, we proposed a field programmable gate array (FPGA) technique to implement TDC which is more suitable for high energy Physics system. In TDC scheme, the timing resolution is more important than the count rates of channel. In order to manage pico-second resolution TDC, we used the delay components of FPGA, utilized the place and route (P&R) delay difference, and then got two ring oscillators. By setting P&R area constraints, we generated two precise ring oscillators with slightly different frequencies. Finally, we evaluated that the period difference of these two ring oscillators was about 60 pico-seconds, timing resolution of TDC.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.2
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• pp.109-117
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• 2022

This paper proposes a method for detecting flight anomalies of drones through the difference between the command of flight controller (FC) and the navigation solution. If the drones make a flight normally, control errors generated by the difference between the desired control command of FC and the navigation solution should converge to zero. However, there is a risk of sudden change or divergence of control errors when the FC control feedback loop preset for the normal flight encounters interferences such as strong winds or navigation sensor abnormalities. In this paper, we propose the method with a deep neural network model that predicts the control error in the normal flight so that the abnormal flight state can be detected. The performance of proposed method was evaluated using the real-world flight data. The results showed that the method effectively detects anomalies in various situation.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.9
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• pp.28-35
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• 1999

In this study, investigation of transient knock characteristics in a spark-ignition engine has been carried out. The universal knock threshold values were found by a DFDD method and a NSDBP method which is a non-dimensional version of the SDBP method. Also modified NSDBP method could be used for transient knock detection. In a commercial ECU , spark timing was retarded from the steady -state spark timing during rapid throttle opening to avoid uncomfortable feeling and knock. Knock usually occurred just after the start of rapid throttle opening when spark timing was set, as values for the steady state condition. We found that air/fuel ratio deeply involved with the knock during transient condition. Due to the difference of initial heat release rate, knock occurred more easily at rich air/fuel ratio than at lean air/fuel ratio.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.2 s.344
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• pp.56-65
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• 2006

In this paper, we introduce modified difference type symbol timing detection method of simple structure and show the relations between S/N ratio and timing detection performance which less influenced by multipath channel delay profile and added noise level and it show very exact GI detection performance characteristics. In the computer simulations, 4 symbol time duration of short and long training of IEEE802.11a standard OFDM frame are used for symbol synchronization timing detection. The computer simulation results show the very exact symbol timing detection performance characteristic within 1 sample error of OFDM signal regardless channel delay profile from minimn phase channels of phase rotation ${\pi}/2$ to non-minimum phase channels of phase rotation ${\pi}/2$ of received OFDM signal and added noise level in channel.

• Journal of the Korean Institute of Landscape Architecture
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• v.25 no.1
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• pp.73-81
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• 1997

This study was conducted to find out the hydroseeding timing of woody plants. Five native plants were used for this experiment and were seeded on the cut slopes by hands in April, May, June, September and October. In order to identify the best seeding time, germination percentage, ground cover rate and plant height were investigated. There was a difference in germination percentage and ground cover rate depending on the seeding time. The results are summerized as follows 1. Characteristics of germination : Seeding was best carried out in spring(May, June) or autumn(September). In spring, Lespedeza cyrtobotrya shows quick germination and rapid growing which can be compared with herbaceous plants using in the hydroseeding. As for Pinus thunbergii, there was little difference in germinatin according to different seeding timing. But Evodia daniellii, Parthenocis년 tricuspidata and Alnus hirsuta seem to need seed treatments to improve the seed germination. 2. Ground cover rate : The most rapid growing plant is Lespedeza cyrtobotrya and the next is Amorpha fruticosa. The other plants show extreamly low ground cover rate, so they seem to be surpressed by herbaceous plants which will be mixed for erosion control. 3. Plant height : On 8 weeks later after seeding, the Lespedeza cyrtobotrya which was seeded in June recorded 17.1cm plant height. It will be enouch height to compete with herbaceous plants. As the Parthenocissus tricuspjdata seeded in May shows 27cm plant length, it can be used more frequently on seeding works if the seed germination were improved. In sum, seeding is best carried out in May. When deciding seeding rate for the purpose of hydroseeding, it will be necessary to adjust the woody plants germination percentage according to seeding timing.

• Journal of Animal Science and Technology
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• v.63 no.2
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• pp.426-439
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• 2021

It is already well known that castration improves marbling quality but exact timing of castration is still highly debated in beef cattle production industry. After castration, blood hormonal changes occur in steer and objective of this study was to investigate the effects of growth hormone (GH) levels on adipocyte differentiation in stromal vascular cells (SVCs) and transdifferentiation into adipocytes in C2C12 myoblasts. Total GH concentrations were measured via enzyme-linked immunosorbent assay (ELISA) in 24 male calves and 4 female calves. Cell proliferation, cellular triglyceride (TG) accumulation, and the cell's lipolytic capability were measured in C2C12 myoblasts and SVCs. Myogenic, adipogenic, and brown adipocyte-specific gene expression was measured via real-time polymerase chain reaction (PCR) using SYBR green. Serum GH levels were the highest in late-castrated calves. Treatment with 5 ng/mL GH resulted in greater TG accumulation as well as increased CCAAT-enhancer-binding protein (C/EBP)α and peroxisome proliferator-activated receptor (PPAR)γ expression compared to that after treatment with 15 ng/mL GH. Treatment with 5 ng/mL GH also resulted in lower myogenin (myo)G and myoD expression compared to that after treatment with 15 ng/mL GH. The expression of bone morphogenetic protein (BMP) 7 after treatment with 5 ng/mL GH was higher than that after treatment with 15 ng/mL GH. But carcass characteristics data showed no significant difference between early and late castrated steers. Therefore, our results indicate that castration timing does not seem to be inevitable determinate of carcass qualities, particularly carcass weight and marbling score in Hanwoo beef cattle.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.4
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• pp.55-60
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• 1983

A new type of digital phase-locked loop (DPLL) that employs a multilevel quantified timing error detector (TED) is proposed and analyzed under the assumption of negligible quantizing effect and no noise. Since the timing error is quantized uniformly, the TED has a linear characteristic. From the linear characteristic of TED, a first order difference equation describing the behavior of the loop is derived. Using the system equation, the loop is analyzed mathematically for phase step and frequency step input. Desired locking condition for the loop to be locked and the lock range for the DPLL's to achieve exact locking independently of initial conditions are ob-tained. And these analyses are confirmed by timing error plane plots and computer simulation.

• Korean Journal of Construction Engineering and Management
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• v.10 no.3
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• pp.62-71
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• 2009

The purpose of this study is to analyze of profitability accordance to the different sales timing in apartment housing development projects. The adapted research method about public apartment hosing development projects by a private construction company is concentrated on the middle and large scale housing. The methodology for analysis of profitability through the change of timing for sales is analysed. According to this methodology, the difference of profitability by different timing of first sales is compared and analyzed. The results of this study are as followed 1)The major factors to affect the profitability for apartment housing development project consist of the timing of sales, the method of payment and the rate of sales. 2) The case study was carried out and then the profitability is analyzed the profitability for the three of cases is got worse when the sale after construction especially on the time of construction progress rate 80% is carried out.