• English Language & Literature Teaching
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• v.7 no.2
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• pp.147-166
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• 2002

The purpose of this paper is to explain stress shift and its following segmental variations when some suffixes are added to the bases. In the past those were analyzed in stress or vowel laxing phenomenon separately, but rather those should be analyzed in one framework compositively. Therefore in this paper I will introduce a new theory, which is known as Harmonic theory, and confirm that it can solve the problems related with stress and vowel laxing simultaneously. The first thing, as a prosodic approach I am going to analyze vowel laxing according to Liberman & Prince (1977), Burzio (1993), and then next to go to the Harmonic theory approach. Within the theory I will analyze the phonological phenomena harmoniously through the important three levels, M-level, W-level, P-level. Therefore this paper is to show that from the comparison between the prosodic analysis and the Harmonic analysis, what is more natural and harmonious analysis is based on the Harmonic approach.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.708-714
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• 2016

In today's semiconductor industry, manufacturing technology is being developed for the purpose of processing large amounts of data and improving the speed of data processing. The packaging process in semiconductor manufacturing is utilized for the purpose of protecting the chips from the external environment and supplying electric power between the terminals. Nowadays, the WLP (Wafer-Level Packaging) process is mainly used in semiconductor manufacturing because of its high productivity. All of the silicon dies on the wafer are subjected to a high pressure and temperature during the molding process, so that die shift and warpage inevitably occur. This phenomenon deteriorates the positioning accuracy in the subsequent re-distribution layer (RDL) process. In this study, in order to minimize the die shift, a vision inspection system is developed to collect the die shift measurement data.

• Safety and Health at Work
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• v.10 no.1
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• pp.109-113
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• 2019

Background: In both developed and developing countries, noise is regarded as the most common occupational hazard in various industries. The present study aimed to examine the effect of sound pressure level (SPL) on serum cortisol concentration in three different times during the night shift. Methods: This case-control study was conducted among 75 workers of an industrial and mining firm in 2017. The participants were assigned to one of the three groups (one control and two case groups), with an equal number of workers (25 participants) in each group. Following the ISO 9612 standard, dosimetry was adopted to evaluate equivalent SPL using a TES-1345 dosimeter. The influence of SPL on serum cortisol concentration was measured during the night shift. The serum cortisol concentration was measured using a radioimmunoassay (RIA) test in the laboratory. Repeated measure analysis of variance and linear mixed models were used with ${\alpha}=0.05$. Results: The results indicated a downward trend in the serum cortisol concentration of the three groups during the night shift. Both SPL and exposure time significantly affected cortisol concentration (p < 0.0001, p < 0.0001). Conversely, age and body mass index had no significant influence on cortisol concentration (p = 0.360, p = 0.62). Conclusion: Based on the obtained results, increasing SPL will lead to enhancement of serum cortisol concentration. Given that cortisol concentration varies while workers are exposed to different SPLs, this hormone can be used as a biomarker to study the effect of noise-induced stress.

• International Journal of Highway Engineering
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• v.14 no.5
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• pp.75-83
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• 2012

PURPOSES: Suggestion of asphalt binder constitutive model based on time-temperature superposition principle and overstress concept in order to describe behavior of asphalt binders. METHODS: A series of temperature sweep tests and multiple stress creep and recovery(MSCR) tests are performed to verify the applicability of time-temperature superposition principle(t-Ts) and to develop viscoelastoplastic constitutive equation based on overstress concept. For the tests, temperature sweep tests at various high temperature and various frequency and MSCR test at $58^{\circ}C$, $64^{\circ}C$ $70^{\circ}C$, $76^{\circ}C$, and $82^{\circ}C$ are performed. From the temperature sweep tests, dynamic shear modulus mastercurve and time-temperature shift function are built and the shift function and MSCR at $58^{\circ}C$ are utilized to determine model coefficients of VBO model. RESULTS: It is observed that the time-temperature shift function built at low strain level of 0.1% is applicable not only to 1.0% strain level temperature sweep test but also maximum 500,00% strain level of MSCR test. As well, the modified VBO model shows perfect prediction on MSCR measured strain at the other temperatures. CONCLUSIONS: The Time-temperature superposition principle stands hold from very low strain level to very high strain level and that the modified VBO model can be applicable for various range of strain and temperature region to predict elastic, viscoelastic, and viscoplastic strain of asphalt binders.

• Journal of the Korean Chemical Society
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• v.44 no.4
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• pp.350-355
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• 2000

The compounds, CaAl$_2$(BO$_3$)$_2$O, SrAl$_2$(BO$_3$)$_2$O and BaAl$_2$(BO$_3$)$_2$O, are good host lattices for highly efficient $Eu^{2+}$ luminescence. The europium emission peaks at 450 nm in $Eu^{2+}$:CaAl$_2$(B0$_3$)$_2$O, 411 nm in $Eu^{2+}$: SrAl$_2$(BO$_3$)$_2$O and 375 nm in $Eu^{2+}$: BaAl$_2$(BO$_3$)$_2$O. The $Eu^{2+}$: CaAl$_2$(BO$_3$)$_2$O Phosphor shows a high output and should be a good maintenance in VUV Xe lamps. It is ideally suited for use in PDP phosphors. The $Eu^{2+}$ ion is interesting because the Stokes shift emission is a strong host dependent. The difference in the Stokes shift is oneimportant factor leadingto a difference in wavelength. If the 5d level of $Eu^{2+}$ ion is lower in energy,according to a decrease in the doping lattice size, then the emission wavelength will be longer and the Stokes shift will be smaller. Therefore, a knowledge of the relationship between the crystal lattice size and the Stokes shift. (orthe energy of the 5d level),is essential for beingable to predict $Eu^{2+}$ emission properties.

• Safety and Health at Work
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• v.7 no.2
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• pp.111-119
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• 2016

Background: Shift work and/or sleep quality may affect health. We investigated whether shift work and sleep quality, separately and jointly, were associated with abnormal levels of triglycerides, total cholesterol (TC), and low-and high-density lipoprotein cholesterol in 360 police officers (27.5% women). Methods: Triglycerides, TC, and high-density lipoprotein were analyzed on the Abbott Architect; low-density lipoprotein was calculated. Shift work was assessed using City of Buffalo payroll work history records. Sleep quality (good, ${\leq}5$; intermediate, 6-8; poor, ${\geq}9$) was assessed using the Pittsburgh Sleep Quality Index questionnaire. A shift work + sleep quality variable was created: day plus good sleep; day plus poor sleep; afternoon/night plus good; and poor sleep quality. Mean values of lipid biomarkers were compared across categories of the exposures using analysis of variance/analysis of covariance. Results: Shift work was not significantly associated with lipids. However, as sleep quality worsened, mean levels of triglycerides and TC gradually increased but only among female officers (age- and race-adjusted p = 0.013 and 0.030, respectively). Age significantly modified the association between sleep quality and TC. Among officers ${\geq}40$ years old, those reporting poor sleep quality had a significantly higher mean level of TC ($202.9{\pm}3.7mg/dL$) compared with those reporting good sleep quality ($190.6{\pm}4.0mg/dL$) (gender- and race-adjusted p = 0.010). Female officers who worked the day shift and also reported good sleep quality had the lowest mean level of TC compared with women in the other three categories (p = 0.014). Conclusion: Sleep quality and its combined influence with shift work may play a role in the alteration of some lipid measures.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.20-23
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• 2008

We proposed a-Si:H TFT (hydrogenated amorphous silicon thin film transistor) level shifter which reduced number of power sources. To reduce the number of power sources from four to two, modified bootstrapped inverter was used for the level shifter. The shift register was verified by PSPICE circuit simulation and fabricated. The fabricated level shifter successfully shifted low input (0 to 5 V) to high level output (-7 to 23 V).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.9C
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• pp.868-875
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• 2003

In this paper, enhanced multiresolution motion estimation(MRME) using reduction of one-pixel shift in wavelet domain is proposed. Conventional multiresolution motion estimation using hierarchical relationship of wavelet coefficient has difficulty for accurate motion estimation due to shift-variant property by decimation process of the wavelet transform. Therefore, to overcome shift-variant property of wavelet coefficient, two level wavelet transform is performed. In order too reduce one-pixel shift on low band signal, S$_4$ band is interpolated by inserting average value. Secondly, one level wavelet transform is applied to the interpolated S$_4$ band. To estimate initial motion vector, block matching algorithm is applied to low band signal S$_{8}$. Multiresolution motion estimation is performed at the rest subbands in low level. According to the experimental results, proposed method showed 1-2dB improvement of PSNR performance at the same bit rate as well as subjective quality compared with the conventional multiresolution motion estimation(MRME) methods and full-search block matching in wavelet domain.

• ETRI Journal
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• v.34 no.6
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• pp.800-806
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• 2012

Transmission performances of direct detection-based 100-Gb/s modulation formats are investigated and compared for metro area optical networks. The effects of optical signal-to-noise ratio sensitivity, chromatic dispersion, cross-channel nonlinearity, and transmission distance on the performance of differential 8-ary phase-shift keying (D8PSK), differential phase-shift keying plus three-level amplitude-shift keying (DPSK+3ASK), and dual-carrier differential quaternary phase-shift keying (DC-DQPSK) are evaluated. The performance of coherent dual-polarization quadrature phase-shift keying (DP-QPSK) with block phase estimation and coherent DP-QPSK with digital differential detection are also presented for reference. According to our analysis, all three direct detection modulation formats could transmit a 100-Gb/s signal over several hundred kilometers of a single-mode fiber link. The results also show that DC-DQPSK outperforms D8PSK and DPSK+3ASK, and the performance of DC-DQPSK is comparable to that of coherent DP-QPSK with digital differential detection. The maximum transmission distance of DC-DQPSK is over 1,000 km, which is enough distance for metro applications.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.10
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• pp.797-810
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• 1990

The error rate equations of digitally modulated signals transmitted through the Gaussian noise and tone multiple interference channel have been derived. Using the derived equations of error probabilities in the environments of Gaussian noise tone interferer and Gaussian noise multiple interferer, the error rate performances of various digitally modulated signals have been evaluated, and compared in graphs as a function of average carrier to tone interferer power ratio(CIR), average carrier to multiple interferer power ratio(CIT) and the average carrer-to-Gaussian noise powr ratio(CIR). In this paper, the modulation schemes such as amplitude shift keying (ASK), phase shift keying(PSK), frequency shift keying(FSK), minimum shift keying(MSK), quadrature amplitud modulation(QAM) and amplitude phase shift keying(APK) have been selected for the study of performance comparison. The results of comparison show us that, in low bits/sec/Hz, PSK is superior to the other schemes, but in high bits/sec/Hz, mixed multi ary type is better than single multi ary type. And in strong noise evironment, the multiple interferer has much influence than tone interferer, however, in low noise environment. the mojor error factor is tone interferer. But tone interference effect nearly disappears over specified CIR level about 20[dB]. And the modulation schemes using amplitude are heavily influenced by multiple interference.