• 제목/요약/키워드: reduced bias

검색결과 284건 처리시간 0.027초

패턴 제작 방법이 플레어스커트의 실루엣에 미치는 영향 (Effect of the Pattern Making Method on the Silhouette of the Flared Skirt)

  • 신영란;추미선
    • 한국의류산업학회지
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    • 제10권6호
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    • pp.989-996
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    • 2008
  • The purpose of this study is to provide the basic knowledge for the pattern development of a flared skirt. Two flat pattern (FP) methods, the concentric circle method and the corrected concentric circle method, and a draping were used for pattern making. Using these patterns, skirts were made with lengthwise grain in the centerline. The influence of pattern making method on the silhouette of the flared skirt was evaluated by the hemlines formed at the skirt worn in a dress form. Moreover, the combined influence of pattern making method and cutting direction on the silhouette of the flared skirt was examined with the draping pattern (DP) skirt and a FP skirt with $45^{\circ}$ bias grain in the centerline. The DP skirt had more uniform nodes and formed a stable wave form than the FP skirts throughout the whole hemlines. The number of nodes was reduced with lining in the two FP skirts, whereas the number of nodes was not changed in the DP skirt. The unit wave form of all the skirts by three patterns showed long loop form, and the slope angles of the unit wave form of the two FP skirts were higher than that of the DP skirt. The silhouette of the flared skirt was highly influenced by the shape of the waist circumference line in patterns. The DP skirt with lengthwise grain in the centerline showed good silhouette with uniform nodes and high marking efficiency, compared to the FP skirt with $45^{\circ}$ bias grain in the centerline.

The Effects of Doping Hafnium on Device Characteristics of $SnO_2$ Thin-film Transistors

  • 신새영;문연건;김웅선;박종완
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2011년도 제40회 동계학술대회 초록집
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    • pp.199-199
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    • 2011
  • Recently, Thin film transistors (TFTs) with amorphous oxide semiconductors (AOSs) can offer an important aspect for next generation displays with high mobility. Several oxide semiconductor such as ZnO, $SnO_2$ and InGaZnO have been extensively researched. Especially, as a well-known binary metal oxide, tin oxide ($SnO_2$), usually acts as n-type semiconductor with a wide band gap of 3.6eV. Over the past several decades intensive research activities have been conducted on $SnO_2$ in the bulk, thin film and nanostructure forms due to its interesting electrical properties making it a promising material for applications in solar cells, flat panel displays, and light emitting devices. But, its application to the active channel of TFTs have been limited due to the difficulties in controlling the electron density and n-type of operation with depletion mode. In this study, we fabricated staggered bottom-gate structure $SnO_2$-TFTs and patterned channel layer used a shadow mask. Then we compare to the performance intrinsic $SnO_2$-TFTs and doping hafnium $SnO_2$-TFTs. As a result, we suggest that can be control the defect formation of $SnO_2$-TFTs by doping hafnium. The hafnium element into the $SnO_2$ thin-films maybe acts to control the carrier concentration by suppressing carrier generation via oxygen vacancy formation. Furthermore, it can be also control the mobility. And bias stability of $SnO_2$-TFTs is improvement using doping hafnium. Enhancement of device stability was attributed to the reduced defect in channel layer or interface. In order to verify this effect, we employed to measure activation energy that can be explained by the thermal activation process of the subthreshold drain current.

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Electrical transport characteristics of deoxyribonucleic acid conjugated graphene field-effect transistors

  • Hwang, J.S.;Kim, H.T.;Lee, J.H.;Whang, D.;Hwang, S.W.
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2011년도 제40회 동계학술대회 초록집
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    • pp.482-483
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    • 2011
  • Graphene is a good candidate for the future nano-electronic materials because it has excellent conductivity, mobility, transparency, flexibility and others. Until now, most graphene researches are focused on the nano electronic device applications, however, biological application of graphene has been relatively less reported. We have fabricated a deoxyribonucleic acid (DNA) conjugated graphene field-effect transistor (FET) and measured the electrical transport characteristics. We have used graphene sheets grown on Ni substrates by chemical vapour deposition. The Raman spectra of graphene sheets indicate high quality and only a few number of layers. The synthesized graphene is transferred on top of the substrate with pre-patterned electrodes by the floating-and-scooping method [1]. Then we applied adhesive tapes on the surface of the graphene to define graphene flakes of a few micron sizes near the electrodes. The current-voltage characteristic of the graphene layer before stripping shows linear zero gate bias conductance and no gate operation. After stripping, the zero gate bias conductance of the device is reduced and clear gate operation is observed. The change of FET characteristics before and after stripping is due to the formation of a micron size graphene flake. After combined with 30 base pairs single-stranded poly(dT) DNA molecules, the conductance and gate operation of the graphene flake FETs become slightly smaller than that of the pristine ones. It is considered that DNA is to be stably binding to the graphene layer due to the ${\pi}-{\pi}$ stacking interaction between nucleic bases and the surface of graphene. And this binding can modulate the electrical transport properties of graphene FETs. We also calculate the field-effect mobility of pristine and DNA conjugated graphene FET devices.

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PV 모듈 내 바이패스 다이오드 손상에 의한 열적 전기적 특성 변화 분석 (Analysis on thermal & electrical characteristics variation of PV module with damaged bypass diodes)

  • 신우균;정태희;고석환;주영철;장효식;강기환
    • 한국태양에너지학회 논문집
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    • 제35권4호
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    • pp.67-75
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    • 2015
  • PV module is conventionally connected in series with some solar cell to adjust the output of module. Some bypass diodes in module are installed to prevent module from hot spot and mismatch power loss. However, bypass diode in module exposed outdoor is easily damaged by surge voltage. In this paper, we study the thermal and electrical characteristics change of module with damaged bypass diode to easily find module with damaged bypass diode in photovoltaic system consisting of many modules. Firstly, the temperature change of bypass diode is measured according to forward and reverse bias current flowing through bypass diode. The maximum surface temperature of damaged bypass diode applied reverse bias is higher than that of normal bypass diode despite flowing equal current. Also, the output change of module with and without damaged bypass diode is observed. The output of module with damaged bypass diode is proportionally reduced by the total number of connected solar cells per one bypass diode. Lastly, the distribution temperature of module with damaged bypass diode is confirmed by IR camera. Temperature of all solar cells connected with damaged bypass diode rises and even hot spot of some solar cells is observed. We confirm that damaged bypass diodes in module lead to power drop of module, temperature rise of module and temperature rise of bypass diode. Those results are used to find module with a damaged bypass diode in system.

Efficacy of topical interventions for temporomandibular disorders compared to placebo or control therapy: a systematic review with meta-analysis

  • Mena, Mariam;Dalbah, Lana;Levi, Lauren;Padilla, Mariela;Enciso, Reyes
    • Journal of Dental Anesthesia and Pain Medicine
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    • 제20권6호
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    • pp.337-356
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    • 2020
  • This systematic review focused on the efficacy of topical products in reducing temporomandibular joint disorder (TMD)-associated pain, in comparison to placebo or control interventions. The EMBASE, Web of Science, Cochrane Library, and MEDLINE via PubMed databases were searched for randomized controlled trials (RCTs) using topical interventions in adults diagnosed with TMD. The pain intensity was the primary outcome, and other clinical findings were the secondary outcomes. The risk of bias was evaluated according to the Cochrane's handbook. The search up to February 7, 2020 identified a total of 496 unduplicated references. Nine RCTs with 355 adult patients diagnosed with TMD were included. The meta-analysis did not show a significant reduction in baseline pain intensity in the nonsteroidal anti-inflammatory drug (NSAIDs) group, when compared to the placebo group (P = 0.288). One study demonstrated a statistically significant pain score decrease for Theraflex-TMJ compared to placebo after 10 d of treatment (P = 0.003) and follow-up, 5 d after the last application (P = 0.027). Ping On reduced pain at 4 weeks of application (P < 0.001) but not after 7 d of application (P = 0.136). In one study, cannabidiol (CBD) significantly improved the pain intensity compared to placebo (P < 0.001). However, no differences were found with capsaicin in the two studies (P = 0.465). Evidence was of low quality because the studies were considered as having an unclear or a high risk of bias and a small number of studies were analyzed. The evidence is not sufficient to support the use of topical NSAIDs and capsaicin, and limited evidence was found for Threraflex-TMJ, bee venom, Ping On, and CBD, with only one study reporting for each. Additional studies are recommended to validate these results.

GloSea5 모형의 한반도 인근 해수면 온도 예측성 평가: 편차 보정에 따른 개선 (Evaluation of Sea Surface Temperature Prediction Skill around the Korean Peninsula in GloSea5 Hindcast: Improvement with Bias Correction)

  • 강동우;조형오;손석우;이조한;현유경;부경온
    • 대기
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    • 제31권2호
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    • pp.215-227
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    • 2021
  • The necessity of the prediction on the Seasonal-to-Subseasonal (S2S) timescale continues to rise. It led a series of studies on the S2S prediction models, including the Global Seasonal Forecasting System Version 5 (GloSea5) of the Korea Meteorological Administration. By extending previous studies, the present study documents sea surface temperature (SST) prediction skill around the Korean peninsula in the GloSea5 hindcast over the period of 1991~2010. The overall SST prediction skill is about a week except for the regions where SST is not well captured at the initialized date. This limited prediction skill is partly due to the model mean biases which vary substantially from season to season. When such biases are systematically removed on daily and seasonal time scales the SST prediction skill is improved to 15 days. This improvement is mostly due to the reduced error associated with internal SST variability during model integrations. This result suggests that SST around the Korean peninsula can be reliably predicted with appropriate post-processing.

해양모니터링 자료의 장기결측 보충 기법 (Long-gap Filling Method for the Coastal Monitoring Data)

  • 조홍연;이기섭;이욱재
    • 한국해안·해양공학회논문집
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    • 제33권6호
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    • pp.333-344
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    • 2021
  • 해양모니터링 자료에서 빈번하게 발생하는 장기결측구간의 자료 보충기법을 제안한다. 제안하는 방법은 결측구간의 장기변동 추세 성분과 단기변동 잔차성분을 추정하여 조합하는 방식으로 결측구간의 미지 정보를 추정한다. 이 방법을 이용하여 울릉도 해상부이 자료의 수온 항목, 약 1개월 정도의 장기결측 구간의 자료를 보충하였으며, 부이에서 관측하는 자료 항목에 대해서도 결측 보충을 수행하였다. 보충된 자료는 항목에 따라 차이를 보이지만 변동양상이 적절하게 재현되는 것으로 파악되었다. 이 방법은 추세추정과 잔차 반영에 따른 편향오차와 분산오차가 발생하지만, 장기결측으로 인한 통계적인 측도 추정의 편향오차는 크게 절감하는 것으로 파악되었다. 결측보충 모형의 추정 RMS 오차의 평균과 90% 신뢰구간은 각각 0.93, 0.35~1.95 범위이다.

A new method of predicting hotspot stresses for longitudinal attachments with reduced element sensitivities

  • Li, Chun Bao;Choung, Joonmo
    • International Journal of Naval Architecture and Ocean Engineering
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    • 제13권1호
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    • pp.379-395
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    • 2021
  • For the complicated structural details in ships and offshore structures, the traditional hotspot stress approaches are known to be sensitive to the element variables of element topologies, sizes, and integration schemes. This motivated to develop a new approach for predicting reasonable hotspot stresses, which is less sensitive to the element variables and easy to be implemented the real marine structures. The three-point bending tests were conducted for the longitudinal attachments with the round and rectangular weld toes. The tests were reproduced in the numerical simulations using the solid and shell element models, and the simulation technique was validated by comparing the experimental stresses with the simulated ones. This paper considered three hotspot stress approaches: the ESM method based on surface stress extrapolation, the Dong's method based on nodal forces along a weld toe, and the proposed method based on nodal forces perpendicular to an imaginary vertical plane at a weld toe. In order to study the element sensitivities of each method, 16 solid element models and 8 shell element models were generated under the bending and tension loads, respectively. The element sensitivity was analyzed in terms of Stress Concentration Factors (SCFs) in viewpoints of two statistical quantities of mean and bias with respect to the reference SCFs. The average SCFs predicted by the proposed method were remarkably in good agreement with the reference SCFs based on the experiments and the ship rules. Negligibly small Coefficients of Variation (CVs) of the SCFs, which is measure of statistical bias, were drawn by the proposed method.

일차성 사구체신염의 육미지황탕과 양약 병용요법에 대한 체계적 문헌고찰 및 메타분석 (The Effect of Combination Therapy of Yukmijihwang-tang and Western Medicine on Primary Glomerulonephritis: Systemic Review and Meta-analysis)

  • 허태영;김예슬;김경민
    • 대한한방내과학회지
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    • 제44권1호
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    • pp.12-34
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    • 2023
  • Objective: This study was conducted to evaluate the effectiveness of the combination therapy of Yukmijihwang-tang and Western medicine on primary glomerulonephritis. Methods: We conducted a search using keywords, such as Yukmijihwang-tang and Liuwei Dihuang, in eight databases (CNKI, CiNii, Pubmed, Embase, Cochrane, Science On, OASIS, RISS). There was no limit to the publication period of the papers. A meta-analysis was conducted and classified according to the outcome measurements, such as the total effective rate (TER), serum creatinine (SCr), and blood urea nitrogen (BUN). Data analysis was performed using the RevMan 5.4.1 software, and Cochrane's risk of bias (ROB) was used to assess the quality of the papers. Results: A total of 12 randomized control trials were selected. The meta-analysis showed that the treatment group combining Yumijihwang-tang and Western medicine was more efficient than the control group using Western medicine alone (RR: 1.29, CI: 1.20 to 1.39 p=<0.00001). The treatment group also reduced the BUN (MD: -2.40, CI: -2.90 to -1.89, p<0.00001) and Scr (MD: -33.34, CI: -40.85 to -25.82, P<0.00001) more than the control group. Conclusion: This study suggests that the combination therapy of Yukmijihwang-tang with Western medicine is effective in treating primary glomerulonephritis. However, these findings should be interpreted cautiously due to the unknown or high risk of bias in the included trials.

A Systematic Review of Kinesiology Taping in Patients With Lymphedema

  • Jaehee Yang;Eun Jin Lim
    • 한국전문물리치료학회지
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    • 제30권4호
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    • pp.288-305
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    • 2023
  • Background: The compression therapy, which is the standard treatment for lymphedema patients, may be difficult to implement and contraindicated to some patients depending on their health condition. Objects: The purpose of this study is to investigate whether kinesiology taping (KT) can be used effectively and safely in the management of lymphedema as an alternative treatment through systematic review and meta-analysis. Methods: In February 2023, the literature was systematically collected through eight search engines with a combination of terms, 'lymphedema' and 'kinesiology taping.' We qualitatively analyzed the differences and safety of KT methods, and quantitatively meta-analyzed the effects of volume reduction in edema, range of motion (ROM), and pain improvement using Review Manager ver. 5. 4. To assess the risk of bias in the randomized controlled trial (RCT) studies, Risk of Bias was used. Results: A total of 616 articles searched and 20 studies were selected, including 12 RCTs and eight case studies. KT intervention could not replace multilayer compression bandage (MLB), but it demonstrated similar or better results compared to compression garment (CG), with reduced pain and improved intervention comfort. Studies reported skin adverse events ranging from 2.5% to 20.68%, with a total adverse event incidence of 7.7%. There was no significant difference in the application method of KT. As a result of the meta-analysis from the 8 RCTs, the KT intervention showed a mean difference (MD) of -7.18 with a 95% confidence interval (CI) [-12.64 to -1.72] in the volume change of lymphedema, while the pain difference was MD 0.82 with CI 95% [0.50 to 1.15], in comparison to the MLB and CG intervention. Conclusion: KT therapy led to a reduction in edema size, volume, pain, and improved ROM and quality of life. KT may be a viable option for lymphedema patients who have trouble applying traditional compression therapies.