• Wind and Structures
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• 제34권6호
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• pp.483-497
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• 2022

Three-dimensional (3D) computational fluid dynamics (CFD) analysis of flow around a hipped-roof building representative of UK inland conditions are conducted. Unsteady simulations are performed using three variations of the k-ϵ RANS turbulence model namely, the Standard, Realizable, and RNG models, and their predictive capability is measured against current European building standards. External pressure coefficients and wind loading are found through the BS 6399-2:1997 standard (obsolete) and the current European standards (BS EN 1991-1-4:2005 and A1:20101). The current European standard provides a more conservative wind loading estimate compared to its predecessor and the k-ϵ RNG model falls within 15% of the value predicted by the current standard. Surface shear stream-traces and Q-criterion were used to analyze the flow physics for each model. The RNG model predicts immediate flow separation leading to the creation of vortical structures on the hipped-roof along with a larger separation region. It is observed that the Realizable model predicts the side vortex to be a result of both the horseshoe vortex and the flow deflected off it. These model-specific aerodynamic features present the most disparity between building standards at leeward roof locations. Finally, pedestrian comfort and safety criteria are studied where the k-ϵ Standard model predicts the most ideal pedestrian conditions and the Realizable model yields the most conservative levels.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권11호
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• pp.3991-4010
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• 2021

The Question Similarity Measurement of Chinese Crop Diseases and Insect Pests (QSM-CCD&IP) aims to judge the user's tendency to ask questions regarding input problems. The measurement is the basis of the Agricultural Knowledge Question and Answering (Q & A) system, information retrieval, and other tasks. However, the corpus and measurement methods available in this field have some deficiencies. In addition, error propagation may occur when the word boundary features and local context information are ignored when the general method embeds sentences. Hence, these factors make the task challenging. To solve the above problems and tackle the Question Similarity Measurement task in this work, a corpus on Chinese crop diseases and insect pests(CCDIP), which contains 13 categories, was established. Then, taking the CCDIP as the research object, this study proposes a Chinese agricultural text similarity matching model, namely, the AgrCQS. This model is based on mixed information extraction. Specifically, the hybrid embedding layer can enrich character information and improve the recognition ability of the model on the word boundary. The multi-scale local information can be extracted by multi-core convolutional neural network based on multi-weight (MM-CNN). The self-attention mechanism can enhance the fusion ability of the model on global information. In this research, the performance of the AgrCQS on the CCDIP is verified, and three benchmark datasets, namely, AFQMC, LCQMC, and BQ, are used. The accuracy rates are 93.92%, 74.42%, 86.35%, and 83.05%, respectively, which are higher than that of baseline systems without using any external knowledge. Additionally, the proposed method module can be extracted separately and applied to other models, thus providing reference for related research.

• Nuclear Engineering and Technology
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• 제54권11호
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• pp.4146-4158
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• 2022

Ultra-high performance concrete (UHPC) has been widely utilized in military and civil protective structures to resist intensive loadings attributed to its excellent properties, e.g., high tensile/compressive strength, high dynamic toughness and impact resistance. At present, aiming to improve the defects of the traditional vertical concrete cask (VCC), i.e., the external storage facility of spent fuel, with normal strength concrete (NSC) shield, e.g., heavy weight and difficult to fabricate/transform, the feasibility of UHPC applied in the shield of VCC is numerically examined considering its high radiation and corrosion resistance. Firstly, the finite element (FE) analyses approach and material model parameters of NSC and UHPC are verified based on the 1/3 scaled VCC tip-over test and drop hammer test on UHPC members, respectively. Then, the refined FE model of prototypical VCC is established and utilized to examine its dynamic behaviors and damage distribution in accidental tip-over and end-drop events, in which the various influential factors, e.g., UHPC shield thickness, concrete ground thickness, and sealing methods of steel container are considered. In conclusion, by quantitatively evaluating the safety of VCC in terms of the shield damage and vibrations, it is found that adopting the 300 mm-thick UHPC shield instead of the conventional 650 mm-thick NSC shield can reduce about 1/3 of the total weight of VCC, i.e., about 50 t, and 37% floor space, as well as guarantee the structural integrity of VCC during the accidental drop simultaneously. Besides, based on the parametric analyses, the thickness of concrete ground in the VCC storage site is recommended as less than 500 mm, and the welded connection is recommended for the sealing method of steel containers.

• 한국환경과학회지
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• 제24권11호
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• pp.1501-1511
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• 2015

As essential trace elements, copper and zinc play important roles in many physiological events in plants. In excess, however, these elements can limit plant growth. This study selected a heavy metal-tolerant plant by analyzing seed germination and biomass of alfalfa (Medicago sativa), canola (Brassica campestris subsp. napus var. nippo-oleifera), Chinese corn (Setaria italica), and a sorghum-sudangrass hybrid (Sorghum bicolor ${\times}$ S. sudanense), and determined heavy metal uptake capacity by analyzing biomass, chlorophyll a fluorescence, and heavy metal contents under high external copper or zinc levels. The seed germination rate and biomass of the sorghum-sudangrass hybrid were higher under copper or zinc stress compared to the other three plants. The plant biomass and photosynthetic pigment contents of the sorghum-sudangrass hybrid seedlings were less vulnerable under low levels of heavy metals (${\leq}50ppm$ copper or ${\leq}400ppm$ zinc). The maximum quantum yield of PSII ($F_v/F_m$) and the maximum primary yield of PSII ($F_v/F_o$) decreased with increasing copper or zinc levels. Under high copper levels, the decline in $F_v/F_m$ was caused only by the decline in $F_m$, and was accompanied by an increase in non-photochemical quenching (NPQ). The $F_v/F_m$ declined under high levels of zinc due to both a decrease in the maximum fluorescence ($F_m$) and an increase in the initial fluorescence ($F_o$), and this was accompanied by a marked decrease in photochemical quenching (qP), but not by an increase in NPQ. Accumulations of copper and zinc were found in both aboveand below-ground parts of plants, but were greater in the below-ground parts. The uptake capacity of the sorghum-sudangrass hybrid for copper and zinc reached 4459.1 mg/kg under 400 ppm copper and 9028.5 mg/kg under 1600 ppm zinc. Our results indicate that the sorghum-sudangrass hybrid contributes to the in situ phytoremediation of copper or zinc polluted soils due to its high biomass yield.

• 유통과학연구
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• 제13권3호
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• pp.69-77
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• 2015

Purpose - The purpose of this study is to examine whether the cash policies of retail firms listed on Korean stock markets are consistent with the evidence provided in the study of Almeida et al. (2004). Liquidity management is an important issue for financially constrained firms relative to financially unconstrained firms. Because there are few sources of external funding, the optimal liquidity policies of financially constrained firms should reflect their own earnings or cash inflows to create opportunities for current and future real investments. According to this simple idea, we estimate the sensitivity of cash to cash flows and simply check whether the estimated sensitivity to cash flows of the cash retained by constrained retail firms is greater than that of the cash retained by unconstrained retail firms. Through this work, we aim to explain why the cash policies of the retail firms listed on the Korean stock markets differ from those of listed manufacturing enterprises. Research design, data, and methodology - To explain a firm's cash holdings, we use only three explanatory variables: earnings before interest and taxes (EBIT), Tobin's q, and size. All the variables are defined as the value of the numerator divided by aggregate assets. Thanks to this definition, it is possible to treat all the sample firms as a single large firm. The sample financial data for this study are collected from the retail enterprises listed on the KOSPI and KOSDAQ markets from 1991 to 2013. We can obtain these data from WISEfn, the financial information company. This study's methodology has its origin in Keynes's simple idea of precautionary liquidity demand: When a firm faces financial constraints, cash savings from earnings or cash inflows become important from the corporate finance perspective. Following this simple idea, Almeida et al. (2004) developed their theoretical model and found empirical evidence that the sensitivity of cash to cash flows varies systematically according to different types of financing frictions. To find more empirical evidence for this idea, we examined the cash flow sensitivity of the cash held by Korean retail firms. Results - Through several robustness tests, we empirically showed that financially constrained Korean retail firms display significant positive propensity to save cash from earnings before interest and taxes, while the estimated cash flow sensitivity of the cash held by unconstrained retail firms is not significant. Despite the relatively low earnings of retail firms, their sensitivity is three times greater than that of manufacturing enterprises. This implies that Korean retail firms have greater intentions of facilitating future investments rather than current investments. Conclusions - The characteristics of the cash policies of Korean retail firms differ from those of manufacturing firms. This contrast may be attributable to industry-oriented policy planning, regulations, and institutional differences. However, the industrial policymakers should observe signals of the long-term growth options of retail firms based on their high propensity to save from their cash inflows.

• Journal of Ginseng Research
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• 제42권4호
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• pp.485-495
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• 2018

Background: The geographical origin of Panax ginseng Meyer, a valuable medicinal plant, is important to both ginseng producers and consumers in the context of economic profit and human health benefits. We, therefore, aimed to discriminate between the cultivation regions of ginseng using the stable isotope ratios of C, N, O, and S, which are abundant bioelements in living organisms. Methods: Six Korean ginseng cultivars (3-yr-old roots) were collected from five different regions in Korea. The C, N, O, and S stable isotope ratios in ginseng roots were measured by isotope ratio mass spectrometry, and then these isotope ratio profiles were statistically analyzed using chemometrics. Results: The various isotope ratios found in P. ginseng roots were significantly influenced by region, cultivar, and the interactions between these two factors ($p{\leq}0.001$). The variation in ${\delta}^{15}N$ and ${\delta}^{13}C$ in ginseng roots was significant for discriminating between different ginseng cultivation regions, and ${\delta}^{18}O$ and ${\delta}^{34}S$ were also affected by both altitude and proximity to coastal areas. Chemometric model results tested in this study provided discrimination between the majority of different cultivation regions. Based on the external validation, this chemometric model also showed good model performance ($R^2=0.853$ and $Q^2=0.738$). Conclusion: Our case study elucidates the variation of C, N, O, and S stable isotope ratios in ginseng root depending on cultivation region. Hence, the analysis of stable isotope ratios is a suitable tool for discrimination between the regional origins of ginseng samples from Korea, with potential application to other countries.

• International journal of advanced smart convergence
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• 제10권4호
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• pp.241-255
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• 2021

The human auricle is the first part to receive sound from the outside. In this part, the frequency range of human recognizable form is divided and organized. In this study, we propose modeling by applying a single sound source to the surface of the human auricle. This means that when the sound pressure of a low frequency (low frequency) sound enters the pinna, the impedance felt at the tip of a part of the non-linear surface of the pinna is mainly due to the tensile force at the end of the part of the non-linear surface of the pinna. By expressing the situation of moving at a very small speed, the characteristic impedance of the pinna was confirmed to be negative infinity, and it was also confirmed that the speed at the tip of a part of the non-linear surface of the pinna was 0 in the anti-resonance state. It was found that the wave propagation phenomenon that determines the characteristics of the filter is determined by how large the wavelength, kL, is compared to the length of the tip of a part of the non-straight surface of the pinna. Humans first receive sounds from outside through their ears. The auricle is non-linear and has a curved shape, and it is known that it analyzes frequencies while receiving external sounds. The human ear has an audible frequency range of 20Hz - 20,000Hz. Through the study, we applied the characteristics of the notch filter to hypothesize that the human audible frequency range is separated from the auricle, and applied filter theory to analyze it, and as a result, meaningful results were obtained. The curved part and the inner part of the auricle function as a trumpet, collecting sounds, and at the same time amplifying the weak sound of a specific band. The point was found and the shape of the envelope detected in the auricle was found. Selectivity for selecting sounds coming from the outside is the formula of the pinna that implements the function of Q. The function of distinguishing human-recognizable sound from the pinna from low to high through frequency analysis is performed in the pinna, and the 2-3kHz area, where human hearing threshold is the most sensitive, is also the acoustic impedance of the most recessed area of the pinna. It can be seen that starting from.

• Asian-Australasian Journal of Animal Sciences
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• 제32권8호
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• pp.1095-1103
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• 2019

Objective: Among stress responses, the unfolded protein response (UPR) is a well-known mechanism related to endoplasmic reticulum (ER) stress. ER stress is induced by a variety of external and environmental factors such as starvation, ischemia, hypoxia, oxidative stress, and heat stress. Inositol requiring enzyme $1{\alpha}$ ($IRE1{\alpha}$)-X-box protein 1 (XBP1) is the most conserved pathway involved in the UPR and is the main component that mediates $IRE1{\alpha}$ signalling to downstream ER-associated degradation (ERAD)- or UPR-related genes. XBP1 is a transcription factor synthesised via a novel mechanism called 'frame switch splicing', and this process has not yet been studied in the horse XBP1 gene. Therefore, the aim of this study was to confirm the frame switch splicing of horse XBP1 and characterise its dynamics using Thoroughbred muscle cells exposed to heat stress. Methods: Primary horse muscle cells were used to investigate heat stress-induced frame switch splicing of horse XBP1. Frame switch splicing was confirmed by sequencing analysis. XBP1 amino acid sequences and promoter sequences of various species were aligned to confirm the sequence homology and to find conserved cis-acting elements, respectively. The expression of the potential XBP1 downstream genes were analysed by quantitative real-time polymerase chain reaction. Results: We confirmed that splicing of horse XBP1 mRNA was affected by the duration of thermal stress. Twenty-six nucleotides in the mRNA of XBP1 were deleted after heat stress. The protein sequence and the cis-regulatory elements on the promoter of horse XBP1 are highly conserved among the mammals. Induction of putative downstream genes of horse XBP1 was dependent on the duration of heat stress. We confirmed that both the mechanisms of XBP1 frame switch splicing and various binding elements found in downstream gene promoters are highly evolutionarily conserved. Conclusion: The frame switch splicing of horse XBP1 and its dynamics were highly conserved among species. These results facilitate studies of ER-stress in horse.

• 대한환경공학회지
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• 제32권12호
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• pp.1087-1093
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• 2010

독립영양탈질은 추가적인 질소 제거를 위해 메탄올과 같은 고가의 외부탄소원을 필요로 하지 않는다는 면에서 효과적이고 경제적인 방법이다. 본 연구에서는 고농도 질소 농도를 함유한 하수에 대한 황탈질 평가를 통해 설계 및 운영인자의 도출에 필요한 기초자료를 확보하고자 하였다. 입상황으로 충진된 황탈질조는 유동형 스폰지 담체를 이용하여 영양염류를 제거하는 고도처리 공정 후단에 파일럿 규모로 설치되었다($Q=18\;m^3/day$). 외부 알칼리 주입 없이 황탈질조 유입수 내 알칼리(평균 $169.4{\pm}20.8\;mg$ $CaCO_3/L$)만을 활용하였고, 2.45시간의 체류시간으로 운영된 황탈질조 내 추가적인 질산성 질소의 제거를 통해 최종 처리수의 총질소가 7.0 mg T-N/L 이하로 도출되었다. 파일럿 설비 평가를 통해 동절기 저수온($15^{\circ}C$ 이하)에서도 60~80%의 안정적인 황탈질 제거효율을 나타내었으며, 2.78 ppm 이내의 Alum 주입 시 황탈질 성능에 거의 영향을 주지 않는 것으로 나타났다. 황탈질조에서 제거된 질산성 질소 대비 소모된 알칼리도는 $4.09{\pm}1.29\;g$ $CaCO_3/g$ ${NO_3}^-$-N로 도출되었고(이론값 4.57 g $CaCO_3/g$ ${NO_3}^-$-N), 황탈질조 유입수 내 질산성 질소의 전환에 필요한 알칼리도 이상을 포함하였다. 입상황의 소모량은 943.8 g S/day로서, 구형입상황의 마모 및 역세 시의 유실 등에 의해 이론적 소모량인 400.1 g S/day 대비 2.4배 정도 높게 나타났다.

• Applied Biological Chemistry
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• 제19권4호
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• pp.202-218
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• 1976

감압(減壓)이 사과저장(貯藏)에 미치는 영향(影響)을 보기 위하여 일정감압(一定減壓)을 유지(維持)시킬 수 있는 감압저장장치(減壓貯藏裝置)를 새로히 고안제작(考案製作)하여서 시료(試料)는 저장성(貯藏性)이 약(弱)하다는 축(祝)을 선정(選定)하여 $25^{\circ}C$에서 상압구(常壓區)와 감압구(減壓區)로 구분(區分)하고 다시 각(各) 구별(區別)로 환경기체조성(環境氣體組成)을 $CO_2$ 0%구(區) 및 $CO_2$ 5%구(區)로 조정(調整)하여 저장중(貯藏中) 호흡(呼吸), ethylene 생성량(生成量) 및 조직내기체조성(組織內氣體組成)의 변화(變化)와 아울러 성분변화(成分變化)를 조사(調査)하였던 바, 1. 조직내기체(組織內氣體)는 감압(減壓)이 설정(設定)이 동시(同時)에 급속(急速)히 조직(組織)밖으로 이동(移動)하여 5분(分) 이내(以內)에 평형(平衡)이 되었음을 보았으며, 2. 호흡량(呼吸量)은 상압구(常壓區)가 감압구(減壓區)보다 높았고 환경기체조성변화(環境氣體組成變化)에 있어서도 $CO_2$ 5%구(區)는 $CO_2$ 0%구(區)에 비하여 호흡량(呼吸量)이 적음을 볼 수 있었다. 그리고 climacteric rise의 발현(發現)도 호흡량(呼吸量)이 낮음과 병행하여 감압구(減壓區)가 상압구(常壓區)보다 지연됨을 볼 수 있었으며 이와같은 것으로 미루어 감압(減壓)이 과실호흡(果實呼吸)을 억제(抑制)하는데 효과적(效果的)인 수단(手段)임을 알 수 있었다. 이와같은 현상(現像)은 R.Q의 변화조사(變化調査)와 조직내기체조성(組織內氣體組成)의 변화조사(變化調査)에서도 찾아 볼 수 있었다. 3. 과실(果實)의 성숙(成熟) hormone인 ethylene의 생성(生成)은 호흡(呼吸)의 climacteric pattern과 병행하는 경향(傾向)이었으며 climacteric maximum stage,에서는 감압구(減壓區)가 상압구(常壓區)보다 높은 경향(傾向)이었으나 post climacteric stage이후부터 낮아짐과 아울러 조직내(組織內) ethylene농도조사(濃度調査)에서 감압구(減壓區)가 상압구(常壓區)보다 낮음을 볼 때 감압(減壓)으로 인(因)하여 과실(果實)의 ethylene생성(生成)이 억제(抑制)되는 것이 아닌가 생각된다. 4. 그리고 외관조사(外觀調査)에서 지색(地色)의 변화(變化)가 늦어짐과 신선도(新鮮度), 부패율(腐敗率), 중량감소(重量減少), 경도(硬度)의 변화(變化)에서도 위와같은 감압(減壓)의 효과(效果)를 찾아 볼 수 있었다. 5. 성분변화(成分變化) 조사(調査)에 있어서도 당분(糖分), vitamin C 및 산(酸)의 변화(變化)가 감압(減壓)이 상압(常壓)보다 적었으며 특(特)히 유기산중(有機酸中) malic acid의 감소억제효과(減少抑制效果)가 감압구(減壓區)에서 크게 나타났다. 이와같은 효과(效果)는 감산비(減酸比)에서 뚜렷함을 알 수 있었다.