• 한국전문물리치료학회지
• /
• 제30권3호
• /
• pp.221-229
• /
• 2023

Background: In modern society, the use of computers accounts for a large proportion of our daily lives. Although substantial research is being actively conducted on musculoskeletal diseases resulting from computer use, there has been a recent surge in interest in improving the working environment for prevention. Objects: This study aimed to examine the effects of posture correction feedback (PCF) on changes in neck posture and muscle activation during computer typing. Methods: The participants performed a computer typing task in two sessions, each lasting 16 minutes. The participant's dominant side was photographed and analyzed using ImageJ software to verify neck posture. Surface electromyography (EMG) was used to confirm the participant's cervical erector spinae (CES) and upper trapezius muscle activities. The EMG signal was analyzed using the percentage of reference voluntary contraction and amplitude probability distribution function (APDF). In the second session, visual and auditory feedback for posture correction was provided if the neck was flexed by more than 15° in the initial position during computer typing. A 20-minute rest period was provided between the two sessions. Results: The neck angle (p = 0.014), CES muscle activity (p = 0.008), and APDF (p = 0.015) showed significant differences depending on the presence of the PCF. Furthermore, significant differences were observed regarding the CES muscle activity (p = 0.001) and APDF (p = 0.002) over time. Conclusion: Our study showed that the feedback system can correct poor posture and reduces unnecessary muscle activation during computer work. The improved neck posture and reduced CES muscle activity observed in this study suggest that neck pain can be prevented. Based on these results, we suggest that the PCF system can be used to prevent neck pain.

• 수면정신생리
• /
• 제16권2호
• /
• pp.85-90
• /
• 2009

목 적: 수면문제와 자살위험의 증가의 연관성에 대한 관심이 증가하고 있다. 자살사고를 보이는 환자에서 수면문제의 호소는 매우 흔한 일이다. 비록 수면문제가 정신과적 질환에 매우 흔한 증상 중 하나이지만, 불면증, 수면과다증, 악몽등과 같은 수면문제는 특히 자살위험이 높은 환자에서 흔함이 보고되었다. 본 연구에서는 수면시간과 자살사고의 연관성에 대해 조사해 보고자 하였다. 방 법: 인천지역에 거주하는 주민 1,000명(남자:여자=500:500명, 평균연령=39.6${\pm}$11.6세, 연령범위=20~77세)을 대상으로 하였다. 전체 대상군의 사회인구학적 정보를 조사하였고, 지난 한달 동안의 수면시간 및 수면습관, Beck 자살사고 척도(Beck Suicide Intent scale;이하 BSI), 우울증 척도(Center for Epidemiologic Study-Depression;이하 CES-D), 분노감 척도(Spielberger State-Trait Anger Expression Inventory;이하 STAXI), 충동성 척도(Barratt Impulsiveness Scale;이하 BIS), 아침형-저녁형척도(Morningness-Eveningness Scale;이하 MES)로 구성된 설문지를 완성하도록 하였다. 결 과: 전체 대상군에서의 상관관계분석에서 나이와 성별을 보정한 후, BSI점수는 CES-D, STAXI, BIS와 유의한양의 상관관계를 보였으며(각각 $r_P$=0.251; p<0.001, $r_P$=0.352: p<0.001, $r_P$=0.175; p<0.001), MES와는 유의한 음의 상관관계를 보였다($r_P$=-0.066; p=0.037). 수면시간은 BSI점수와는 유의한 상관관계를 보이지 않았다($r_P$=-0.054; p=0.091). 전체 대상군에서 BSI를 종속변수로 하고, 나이, 성별, 가족내 소득, 정신질환의 가족력, 교육, 결혼상태, 종교의 사회인구학적 변수와 CES-D 점수, STAXI 점수, BIS 점수, MES 점수, 6시간 이하나 10시간 이상의 수면시간을 갖는 군을 독립변수로 선형회귀분석을 시행하였다. 정신질환의 가족력, CES-D 점수, STAXI 점수, 6시간 이하나 10시간 이상의 수면시간이 유의하게 자살사고 점수를 예측하였다(F=17.837, adjusted $R^2$=0.166, 각각 p=0.003, p<0.001, p<0.001, p=0.003). 경도 이상의 우울증상이 있는 군으로 한정하였을 때에도, 같은 변인들이 자살사고를 유의하게 예측하였는데, 이 모형이 가지는 설명력은 우울한 집단에서 더 높았다(F=9.920, adjusted $R^2$=0.298). 결 론: 본 연구결과는 주관적 보고에 기초한 6시간 이하의 짧은 수면시간뿐 아니라 10시간 이상의 긴 수면시간도 자살사고와 유의한 연관성이 있음을 제시한다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
• /
• pp.276.2-276.2
• /
• 2016

Dye-sensitized solar cells (DSCs) are promising candidates for light-to-energy conversion devices due to their low-cost, easy fabrication and relative high conversion efficiency. An important component of DSCs is counter electrode (CE) collect electrons from external circuit and reduct I3- to I-. The conventional CEs are thermally decomposed Pt on fluorine-doped tin oxide (FTO) glass substrates, which have shown excellent performance and stability. However, Pt is not suitable in terms of cost effect. In this report, we demonstrated that nickel sulfide thin films by atomic layer deposition (ALD)-using Nickel(1-dimethylamino-2-methyl-2-butanolate)2 and hydrogen sulfide at low temperatures of $90-200^{\circ}C$-could be good CEs in DSCs. Notably, ALD allows the thin films to grow with good reproducibility, precise thickness control and excellent conformality at the angstrom or monolayer level. The nickel sulfide films were characterized using X-ray photoelectron spectroscopy, scanning electron microscopy, X-ray diffraction, hall measurements and cyclic voltammetry. The ALD grown nickel sulfide thin films showed high catalytic activity for the reduction of I3- to I- in DSC. The DSCs with the ALD-grown nickel sulfide thin films as CEs showed the solar cell efficiency of 7.12% which is comparable to that of the DSC with conventional Pt coated counter electrode (7.63%).

• 조명전기설비학회논문지
• /
• 제23권9호
• /
• pp.55-61
• /
• 2009

본 논문에서는 구역전기사업자를 구성하는데 적용하기 위해, 기존의 최적화 기법인 Discrete Particle Swarm Optimization (DPSO) 알고리즘을 개량한 Phasor DPSO (PDPSO) 알고리즘을 새롭게 제시한다. 구역전기사업자는 전력구입 뿐만 아니라 전력판매도 가능하고, 미리 계약한 수용가의 전력부하에게 전력을 공급할 의무가 있다. 하나의 배전계통에 다수의 구역전기사업자가 존재할 경우, 해당 배전계통 내의 모든 수용가에게 최소의 운영비용으로 전력을 공급하기 위해서는 다수 구역전기사업자 간에 구성형태를 조정할 필요가 있다. 이에 적용할 최적화 기법으로 본 논문은 PDPSO 알고리즘을 제안하며, 제안된 알고리즘의 각 개체는 기존의 다변수 벡터 대신 크기와 위상각으로 이루어진 다변수 페이저 값을 갖는다.

• 한국수학사학회지
• /
• 제30권4호
• /
• pp.233-246
• /
• 2017

$Ces{\grave{a}}ro$ summability is a generalized convergence criterion for infinite series. We have investigated the classical results of summability for Fourier series from 1897 to 1957. In this paper, we are concerned with the summability and summation methods for Fourier Series from 1960 to 2010. Many authors have studied the subject during this period. Especially, G.M. Petersen,$K{\hat{o}}si$ Kanno, S.R. Sinha, Fu Cheng Hsiang, Prem Chandra, G. D. Dikshit, B. E. Rhoades and others had studied neoclassical results on the summability of Fourier series from 1960 to 1989. We investigate the results on the summability for Fourier series from 1990 to 2010 in section 3. In conclusion, we present the research minor lineage on summability for Fourier series from 1960 to 2010. $H{\ddot{u}}seyin$ Bor is the earliest researcher on ${\mid}{\bar{N}},p_n{\mid}_k$-summability. Thus we consider his research results and achievements on ${\mid}{\bar{N}},p_n{\mid}_k$-summability and ${\mid}{\bar{N}},p_n,{\gamma}{\mid}_k$-summability.

• Journal of Korean Neurosurgical Society
• /
• 제56권6호
• /
• pp.517-520
• /
• 2014

Cauda equina syndrome (CES) associated with dural ectasia is a rare neurologic complication in patients with longstanding ankylosing spondylitis (AS). We report a 68-year-old male with a 30-year history of AS who presented a typical symptom and signs of progressive CES, urinary incontinence and neuropathic pain of the lumbosacral radiculopathy. Computed tomography (CT) and magnetic resonance imaging (MRI) findings showed the unique appearances of dural ectasia, multiple dural diverticula, erosion of posterior element of the lumbar spine, tethering of the conus medullaris and adhesion of the lumbosacral nerve roots to the posterior aspect of the dural ectasia. Considering the progressive worsening of the clinical signs, detethering of the conus medullaris through resection of the filum terminale was performed through a limited laminectomy. However, the urinary incontinence did not improve and there was a partial relief of the neuropathic leg pain only. The possible pathogenetic mechanism of CES-AS and the dural ectasia in this patient with longstanding AS are discussed with a literature review.

• 전자공학회논문지S
• /
• 제35S권6호
• /
• pp.156-163
• /
• 1998

ATM 망에서는 전화서비스와 같은 CBR(Constant Bit Rate) 음성을 처리하기 위해서 AAL1 CES(Circuit Emulation Service)를 제시하고 있다. 본 논문에서는 ATM 망에서 CES를 이용한 전화서비스를 할 경우에 ATM 망의 셀 손실률에 따른 전화음성의 품질평가 실험을 하였다. 이를 위해 structured/unstructured DS1 구조의 ATM 망을 모델링 하였으며, 전화음성의 품질평가 실험에서 객관적인 품질평가로는 SNR을 주관적인 품질평가 방법인 MOS를 사용하였다. 시뮬레이션 결과 ATM CES에서 셀 손실률이 $10^{-3}$ 이하일 경우 MOS 4.0, SNR 30dB 이상의 양호한 음질을 얻을 수 있음을 보였다.

• Journal of applied mathematics & informatics
• /
• 제29권1_2호
• /
• pp.227-245
• /
• 2011

In this paper, we introduce a new iterative method for finding a common element of the set of solutions for mixed equilibrium problem, the set of solutions of the variational inequality for a ${\beta}$inverse-strongly monotone mapping and the set of fixed points of a family of finitely nonexpansive mappings in a real Hilbert space by using the viscosity and Ces$\`{a}$ro mean approximation method. We prove that the sequence converges strongly to a common element of the above three sets under some mind conditions. Our results improve and extend the corresponding results of Kumam and Katchang [A viscosity of extragradient approximation method for finding equilibrium problems, variational inequalities and fixed point problems for nonexpansive mapping, Nonlinear Analysis: Hybrid Systems, 3(2009), 475-86], Peng and Yao [Strong convergence theorems of iterative scheme based on the extragradient method for mixed equilibrium problems and fixed point problems, Mathematical and Computer Modelling, 49(2009), 1816-828], Shimizu and Takahashi [Strong convergence to common fixed points of families of nonexpansive mappings, Journal of Mathematical Analysis and Applications, 211(1) (1997), 71-83] and some authors.

• Steel and Composite Structures
• /
• 제29권6호
• /
• pp.735-748
• /
• 2018

In this paper, the cyclic behavior of steel beam-concrete encased steel (CES) column joints was investigated experimentally and numerically. Three frame middle joint samples with varying concrete slab widths were constructed. Anti-symmetrical low-frequency cyclic load was applied at two beam ends to simulate the earthquake action. The failure modes, hysteretic behavior, ultimate load, stiffness degradation, load carrying capacity degradation, displacement ductility and strain response were investigated in details. The three composite joints exhibited excellent seismic performance in experimental tests, showing high load-carrying capacity, good ductility and superior energy dissipation ability. All three joint samples reached their ultimate loads due to shear failure. Numerical results from ABAQUS modelling agreed well with the test results. Finally, the effect of the concrete slab on ultimate load was analyzed through a parametric study on concrete strength, slab thickness, as well as slab width. Numerical simulation showed that slab width and thickness played an important role in the load-carrying capacity of such joints. As a comparison, the influence of concrete grade was not significant.

• PNF and Movement
• /
• 제20권1호
• /
• pp.41-49
• /
• 2022

Purpose: The aim of this study was to examine the effects of vibration exercise on balance control ability, gait ability, and depression in the elderly. Methods: A total of 24 elderly subjects were recruited and randomized into an experimental (n = 12) or a control (n = 12) group. The experimental group performed both a vibration and a stabilization exercise, and the control group performed a stabilization exercise alone. Balance ability was measured using the functional reach test (FRT), gait ability was measured using the timed up and go test (TUGT), and depression was measured using the Center for Epidemiologic Studies Depression Scale (CES-D). Results: The experimental and control groups showed significant differences for all pre- and post-experiment FRT, TUGT, and CES-D measurements (p <0.05). In a comparison between the two groups, the experimental group in which vibration exercise was applied showed more significant difference in FRT, TUGT, and CES-D than the control group (p <0.05). Conclusion: This study showed vibration exercise to be effective in balance control ability, gait ability, and depression in the elderly.