• Title/Summary/Keyword: Asymmetric distribution

Search Result 460, Processing Time 0.028 seconds

Connection Performance of Steel Moment Frame with Out-of-Plane Beam Skew (면외방향 어긋난 보를 갖는 철골모멘트골조의 접합부 성능)

  • Hong, Jong-Kook
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.26 no.2
    • /
    • pp.84-91
    • /
    • 2022
  • This study investigated the behavior of out-of-plane skewed moment connections that were designed as IMFs, as per the Korean standards. A total of 14 finite element models were constructed with the consideration of two types (single- and double-sided connections) and four levels of skew angle (0°, 10°, 20°, and 30°). The results indicated that the skewed connections considered in this study met the acceptance criteria for IMFs given by the codes. However, the load-carrying capacities of skewed connections were decreased as the skew angle increased. For the connection with a skew angle of 30°, the peak load was noted to be 13% less and the energy dissipation capacity could be 26% less than that of non-skewed connection. In addition, because of the skewed nature, the stress distribution in the skewed beam flange near the connection was asymmetric and the stresses were concentrated on the beam inner flange. Column twisting induced by the skewed configuration was very small and negligible in the beam and column combination considered in this study.

The Impact of COVID-19 Pandemic on the Relationship Structure between Volatility and Trading Volume in the BTC Market: A CRQ approach (COVID-19 팬데믹이 BTC 변동성과 거래량의 관계구조에 미친 영향 분석: CRQ 접근법)

  • Park, Beum-Jo
    • Economic Analysis
    • /
    • v.27 no.1
    • /
    • pp.67-90
    • /
    • 2021
  • This study found an interesting fact that the nonlinear relationship structure between volatility and trading volume changed before and after the COVID-19 pandemic according to empirical analysis using Bitcoin (BTC) market data that sensitively reflects investors' trading behavior. That is, their relationship appeared positive (+) in a stable market state before COVID-19 pandemic, as in theory based on the information flow paradigm. In a state under severe market stress due to COVID-19 pandemic, however, their dependence structure changed and even negative (-). This can be seen as a consequence of increased market stress caused by COVID-19 pandemics from a behavioral economics perspective, resulting in structural changes in the asset market and a significant impact on the nonlinear dependence of volatility and trading volume (in particular, their dependence at extreme quantiles). Hence, it should be recognized that in addition to information flows, psychological phenomena such as behavioral biases or herd behavior, which are closely related to market stress, can be a key in changing their dependence structure. For empirical analysis, this study performs a test of Ross (2015) for detecting a structural change, and proposes a Copula Regression Quantiles (CRQ) approach that can identify their nonlinear relationship structure and the asymmetric dependence in their distribution tails without the assumption of i.i.d. random variable. In addition, it was confirmed that when the relationship between their extreme values was analyzed by linear models, incorrect results could be derived due to model specification errors.

The Impact of Market Environments on Optimal Channel Strategy Involving an Internet Channel: A Game Theoretic Approach (시장 환경이 인터넷 경로를 포함한 다중 경로 관리에 미치는 영향에 관한 연구: 게임 이론적 접근방법)

  • Yoo, Weon-Sang
    • Journal of Distribution Research
    • /
    • v.16 no.2
    • /
    • pp.119-138
    • /
    • 2011
  • Internet commerce has been growing at a rapid pace for the last decade. Many firms try to reach wider consumer markets by adding the Internet channel to the existing traditional channels. Despite the various benefits of the Internet channel, a significant number of firms failed in managing the new type of channel. Previous studies could not cleary explain these conflicting results associated with the Internet channel. One of the major reasons is most of the previous studies conducted analyses under a specific market condition and claimed that as the impact of Internet channel introduction. Therefore, their results are strongly influenced by the specific market settings. However, firms face various market conditions in the real worlddensity and disutility of using the Internet. The purpose of this study is to investigate the impact of various market environments on a firm's optimal channel strategy by employing a flexible game theory model. We capture various market conditions with consumer density and disutility of using the Internet.

    shows the channel structures analyzed in this study. Before the Internet channel is introduced, a monopoly manufacturer sells its products through an independent physical store. From this structure, the manufacturer could introduce its own Internet channel (MI). The independent physical store could also introduce its own Internet channel and coordinate it with the existing physical store (RI). An independent Internet retailer such as Amazon could enter this market (II). In this case, two types of independent retailers compete with each other. In this model, consumers are uniformly distributed on the two dimensional space. Consumer heterogeneity is captured by a consumer's geographical location (ci) and his disutility of using the Internet channel (${\delta}_{N_i}$).
    shows various market conditions captured by the two consumer heterogeneities.
    (a) illustrates a market with symmetric consumer distributions. The model captures explicitly the asymmetric distributions of consumer disutility in a market as well. In a market like that is represented in
    (c), the average consumer disutility of using an Internet store is relatively smaller than that of using a physical store. For example, this case represents the market in which 1) the product is suitable for Internet transactions (e.g., books) or 2) the level of E-Commerce readiness is high such as in Denmark or Finland. On the other hand, the average consumer disutility when using an Internet store is relatively greater than that of using a physical store in a market like (b). Countries like Ukraine and Bulgaria, or the market for "experience goods" such as shoes, could be examples of this market condition. summarizes the various scenarios of consumer distributions analyzed in this study. The range for disutility of using the Internet (${\delta}_{N_i}$) is held constant, while the range of consumer distribution (${\chi}_i$) varies from -25 to 25, from -50 to 50, from -100 to 100, from -150 to 150, and from -200 to 200.
    summarizes the analysis results. As the average travel cost in a market decreases while the average disutility of Internet use remains the same, average retail price, total quantity sold, physical store profit, monopoly manufacturer profit, and thus, total channel profit increase. On the other hand, the quantity sold through the Internet and the profit of the Internet store decrease with a decreasing average travel cost relative to the average disutility of Internet use. We find that a channel that has an advantage over the other kind of channel serves a larger portion of the market. In a market with a high average travel cost, in which the Internet store has a relative advantage over the physical store, for example, the Internet store becomes a mass-retailer serving a larger portion of the market. This result implies that the Internet becomes a more significant distribution channel in those markets characterized by greater geographical dispersion of buyers, or as consumers become more proficient in Internet usage. The results indicate that the degree of price discrimination also varies depending on the distribution of consumer disutility in a market. The manufacturer in a market in which the average travel cost is higher than the average disutility of using the Internet has a stronger incentive for price discrimination than the manufacturer in a market where the average travel cost is relatively lower. We also find that the manufacturer has a stronger incentive to maintain a high price level when the average travel cost in a market is relatively low. Additionally, the retail competition effect due to Internet channel introduction strengthens as average travel cost in a market decreases. This result indicates that a manufacturer's channel power relative to that of the independent physical retailer becomes stronger with a decreasing average travel cost. This implication is counter-intuitive, because it is widely believed that the negative impact of Internet channel introduction on a competing physical retailer is more significant in a market like Russia, where consumers are more geographically dispersed, than in a market like Hong Kong, that has a condensed geographic distribution of consumers.
    illustrates how this happens. When mangers consider the overall impact of the Internet channel, however, they should consider not only channel power, but also sales volume. When both are considered, the introduction of the Internet channel is revealed as more harmful to a physical retailer in Russia than one in Hong Kong, because the sales volume decrease for a physical store due to Internet channel competition is much greater in Russia than in Hong Kong. The results show that manufacturer is always better off with any type of Internet store introduction. The independent physical store benefits from opening its own Internet store when the average travel cost is higher relative to the disutility of using the Internet. Under an opposite market condition, however, the independent physical retailer could be worse off when it opens its own Internet outlet and coordinates both outlets (RI). This is because the low average travel cost significantly reduces the channel power of the independent physical retailer, further aggravating the already weak channel power caused by myopic inter-channel price coordination. The results implies that channel members and policy makers should explicitly consider the factors determining the relative distributions of both kinds of consumer disutility, when they make a channel decision involving an Internet channel. These factors include the suitability of a product for Internet shopping, the level of E-Commerce readiness of a market, and the degree of geographic dispersion of consumers in a market. Despite the academic contributions and managerial implications, this study is limited in the following ways. First, a series of numerical analyses were conducted to derive equilibrium solutions due to the complex forms of demand functions. In the process, we set up V=100, ${\lambda}$=1, and ${\beta}$=0.01. Future research may change this parameter value set to check the generalizability of this study. Second, the five different scenarios for market conditions were analyzed. Future research could try different sets of parameter ranges. Finally, the model setting allows only one monopoly manufacturer in the market. Accommodating competing multiple manufacturers (brands) would generate more realistic results.

  • PDF
  • Problems of Water Use and Estimation of Water Right in North Han River Shared by North and South Korea (II) - Estimation of Water Right in Downstream Area (남북공유하천 북한강의 물이용 문제점 및 수리권 추정 (II) -하류유역 수리권 추정)

    • Ahn, Jong-Seo;Lee, Gwang-Man;Jung, Kwan-Sue
      • Journal of Korea Water Resources Association
      • /
      • v.44 no.4
      • /
      • pp.315-325
      • /
      • 2011
    • There are not many practical measures to solve a water conflict, when a hydromorphologically asymmetric situation in international rivers exists whereby downstream users may not affect upstream users but upstream users do cause downstream impacts. In taking advantage of this merit, North Korea has built Imnam Dam in upstream of North Han River and uses water for trans-basin hydropower generation. As an impact of this dam South Korean' area as a downstream user has been suffered from water deficit and dry river. It is very critical for South Korea to solve a key problem such as water allocation for water supply and river maintenance. Therefore, this study is aim to suggest alternatives for equitable water allocation in consideration of special circumstances between the South and the North. For this, reviewing the allocation methods of water rights is carried using lessons obtained from international river cases. The results show that the minimum desired streamflow is calculated at 7.3 $m^3/sec$; water budget analysis by the equitable distribution of streamflows at the border line of the North Han River, the difference in water supply deficiency is at 3.7 $m^3/sec$ before and after Imnam Dam; in the determined distribution method, the difference in water deficiency is at 11.38 $m^3/sec$. These results show that South Korea should be secured 11.38 $m^3/sec$ from North Korean's Imnam Dam in respective of water use right and sound river maintenance.

    A Comparative Study on Closed vs. Open Endotracheal Suctioning on the Newborn Infants Treated with Ventilator (인공호흡기 사용 신생아의 폐쇄형과 개방형 기관흡인에 관한 연구)

    • Park, Jeong-Won;Park, Yeong-Ae
      • 아동간호학회:학술대회논문집
      • /
      • 1997.11a
      • /
      • pp.61-74
      • /
      • 1997
    • Endotracheal suctioning is a routine procedure used for clearing secretions from the airway of the intubated infant. This procedure is not without complications. Endotracheal suctioning has been associated with decreases in $PaO_2$, decreases in systemic venous oxygenation, alterations in mean arterial Pressure, disturbances in cardiac rhythm and development of nosocomial pneumonia. So several endotracheal suctioning techniques have been developed to prevent these blown complications. Another method of Endotracheal suctioning eliminates the risk associated with disconnecting the infant from the ventilatior to perform the suctioning procedure. Studies examining closed endotracheal suctioning methods reported that the closed method results in less arterial oxygen saturation, and less systemic venous oxygen desaturation. However those studies have focused on adult patients, and there have been no published studies for newborn infants. The specific purpose of this study is to investigate the two methods and to make a comparison in terms of (1)variations in $SaO_2$, heart rate, and respiration rate appeared before and after the endotracheal suctioning; (2)difference in occurrence of nosocomial infection; (3)difference in recovery time to arrive at pre-suction baseline after suctioning and in nursing time taken for the suctioning. The present study is based on the data obtained from two groups of newborn infants : one group comprises 8 infants with closed suctioning (a total of 304 suctions) among 17 infants treated with ventilator and the other group 9 infants with open method (a total of 629 suctions). The data were analyzed using the SPSS statistical program package. As the distribution test on dependent variables with the Skewnesser Shapiro Wilk test showed an asymmetric distribution, the Wilcoxon Matched-pairs Singled- Ranks test was used for the test of variations in $SaO_2$, heart rate, and respiration rate appeared before and after the endotracheal suctioning. The difference in $SaO_2$ recovery time and nursing time was analyzed with the Mann-Whitney U-Test. The difference in physiologic consequences and occurrence of nosocomial infection between the two groups was analyzed with the Fisher's Exact Test. The results of the study are summarized as follows. For the hypothesis 1 (There would be a difference in $SaO_2$, heart rate, and respiration rate before and after suctioning between the two suctioning methods), the difference in $SaO_2$ turns out to be statistically significant (P=0.015), but heart rate and respiration rate do not procedure a notable difference (P=0.630). The hypothesis 2 (There would be a difference in rates at which a complication arises after suctioning between the two groups) does not prove to be statistically valid (P=0.246). For the hypothesis 3(There would be a difference in $SaO_2$ recovery time and nursing time between the two groups), the average $SaO_2$ recovery time after suctioning turned out to have somewhat significant difference (P=0.064), however the difference in nursing time taken for the suctioning was not statistically significant (P=0.610). The analyses indicate that the closed endotracheal suctioning is more efficient as compared with the open method, in maintaining pre-suction baseline $SaO_2$ and a rapid recovery of newborn infants. Based on these results we suggust to apply the closed method to newborn infants in the ventilation treatment. We also suggest to extend the investigation to include the comparison of suction cost taking into account the case in which a complication arises after endotracheal suctioning between the two groups.

    • PDF

    Geological Structures of the Limesilicates in the Songgang-ri, Cheongsong-gun, Korea (청송군 송강리 석회규산염암류의 지질구조)

    • Kang, Ji-Hoon
      • The Journal of the Petrological Society of Korea
      • /
      • v.27 no.3
      • /
      • pp.139-151
      • /
      • 2018
    • The Songgang-ri area, Cheongsong-gun, which is located in the Sobaeksan province of Yeongnam Massif near the southwestern boundary of Yeongyang subbasin of Gyeongsang Basin, consists of age unknown metamorphic rocks (banded gneiss, granitic gneiss, limesilicates) and age unknown igneous rock (granite gneiss) which intrudes them. This paper researched the geological structures of the Songgang-ri area from the geometric and kinematic features and the developing sequence of multi-deformed rock structures in the geological outcrops exposed about 170 m along the riverside of Yongjeoncheon in the eastern part of Songgang village, Songgang-ri. In the Songgang-ri geological outcrops are recognized three times (Fn, Fn+1, Fn+2) of folding, three times (Dk-I, Dk-II, Dk-III) intrusion of acidic dykes, one time of faulting, which are different in deformation and intrusion timing each other. These geological structures are at least formed by five times (Dn, Dn+1, Dn+2, Dn+3, Dn+4) of deformation. The Dn deformation is recognized by Fn fold which axial surface is parallel to the regional foliation. The Dn+1 intruded the (E)NE trending Dk-I dyke in the earlier phase and formed the NW trending Fn+1 fold in the later phase under compression of (E)NE-(W)SW direction. There are tight, isoclinal, intrafolial folds, boudinage, ${\sigma}$- or ${\delta}$-type boudins, asymmetric fold, C' shear band as the major deformed rock structures. The Dn+2 intruded the (N)NW trending Dk-II dyke in the earlier phase and formed NE trending Fn+2 fold in the later phase under compression of (N)NW-(S)SE direction. There are open fold and folded boudinage as those. The Dn+2 intruded the Dk-III dyke which cuts the Dk-I and Dk-II dykes and the axial surface of Fn+2 fold. The Dn+3 formed the left-handed reverse oblique-slip fault of NNE trend in which hanging wall moves into the SSE direction. Considering in that such five times of deformation recognized in the Songgang-ri geological outcrops are closely connected to the distribution and geological structure of the constituents in the more regional area as well as Songgang-ri area, the research result is expected to play a great data in clarifying and understanding the geological structure and its development process of the surrounding and boundary constituents of the Yeongnam Massif and Gyeongsang Basin.

    Geological Structure of Okcheon Metamorphic Zone in the Miwon-Boeun area, Korea (미원-보은지역에서 옥천변성대의 지질구조)

    • 강지훈;이철구
      • The Journal of the Petrological Society of Korea
      • /
      • v.11 no.3_4
      • /
      • pp.234-249
      • /
      • 2002
    • The Miwon-Boeun area in the central and northern part of Okcheon metamorphic zone, Korea, is composed of Okcheon Supergroup and Mesozoic Cheongju and Boeun granitoids which intruded it. The Okcheon Supergroup consists mainly of quartzite (Midongsan Formation), meta-calcareous rocks (Daehyangsan Formation, Hwajeonri Formation), meta-psammitic rocks (Unkyori Formation), meta-politic rocks (Munjuri Formation), meta-conglomeratic rocks (Hwanggangni Formation) in the study area, showing a zonal distribution of NE trend. Its' general trend is locally changed into NS to EW trend in and around high-angle fault of NS or NW trend. This study focused on deformation history of the Okcheon Supergroup, suggesting that the geological structure was formed at least by four phases of deformation. (1) The first phase of deformation occurred under ductile shear deformation of top-to-the southeast movement, forming sheath fold or A-type fold, asymmetric isoclinal fold, NW-SE trending stretching lineation. (2) The second phase of deformation took place under compression of NW-SE direction, forming subhorizontal, tight upright fold of M trend in the earlier phase, and formed semi-brittle thrust fault (Guryongsan Thrust Fault) of top-to-the southeast movement and associated snake-head fold in the later phase. (3) The third phase of deformation formed subhorizontal, open recumbent fold through gravitational or extensional collapses which might be generated from crustal thickening and gravitational instability. (4) The fourth phase of deformation formed moderately plunging, steeply inclined kink fold related to high-angle faulting, being closely connected with the local change of NE-trending regional foliation into NS to EW direction of strike in the vicinity of the high-angle fault.

    The Financing Behavior and Financial Structure Determinants of Korean Manufacturing Firms (한국제조기업의 자금조달행태와 재무구조 결정요인에 관한 연구)

    • Shin, Dong-Ryung
      • The Korean Journal of Financial Management
      • /
      • v.23 no.2
      • /
      • pp.109-141
      • /
      • 2006
    • The central factor in the pecking order theory of financial structure is the asymmetric distribution of information between managers and less-informed outside investors. Myers and Majluf (1984) show that this asymmetry leads managers to prefer internal funds to external funds. Funds are raised through equity issues only after the capacity to issue debt has been exhausted. In contrast, according to static tradeoff theory, an optimum financial structure exists by the tradeoff between tax saving by debt and bankruptcy costs. This study examines the recent changes of Korean firms' financial structure and financing behavior and the determinants of financial structure. The sample of firms comes from the period of $1996{\sim}2004$, and the number of firms is 32,003. The major findings are as follows. First, in contrast with previous studies using US firms as sample, Korean firms have been using debt financing as their major financing instrument. Especially, the firms in the fund deficit situation relies much more on $long{\sim}term$ and $short{\sim}term$ debts rather than on equity issues. Second, as is the case with previous studies using US firms sample indicates, the financing deficit variable can not explain perfectly the net debt issue. However, compared with net equity issue variable, net debt issue variable is more closely related to the financing deficit variable. Third, when financing deficit variable is added to the current list of explanatory variables of financial structure determinants model, it has a significant and positive explanatory power. In addition, the coefficients of determinants are much improved. Thus, it is concluded that although pecking order theory is not perfect, it appears to be more useful compared to static tradeoff theory, at least in explaining the recent financing behavior of Korean manufacturing firms.

    • PDF

    The Effect of Non Magnetic ion Substitution for the FeCr2-xMxS4(M=Ga, In) by Mossbauer Spectroscopy (비자성 이온 Ga, In이 치환된 유화물 스피넬의 뫼스바우어 분광학 연구)

    • Son, Bae-Soon;Kim, Sam-Jin;Kim, Chul-Sung
      • Journal of the Korean Magnetics Society
      • /
      • v.16 no.1
      • /
      • pp.6-10
      • /
      • 2006
    • The sulphur spinel $FeCr_{2-x}M_xS_4$(M=Ga, In) have been studied with Mossbauer spectroscopy, x-ray diffraction (XRD), and vibrating sample magnetometer. The XRB patterns for samples $FeCr_{2-x}M_xS_4$(M=Ga, In: x=0.1, 0.3) reveal a single phase, which the Ga and In ions are partially occupied to the tetrahedral (A) site. The Neel temperature for the Ga substituted samples increases from 180 to 188 K, with increase from x=0.1 to 0.3. While, it decreases from 173 to 160 K, for the In substituted samples of the x=0.1 and 0.3, respectively. The Mossbauer spectra were collected from 4.2 K to room temperature. We have analyzed the Mossbauer spectra using eight Lorentzian lines fitting method for the $FeCr_{2-x}In_xS_4$(x=0.1) at 4.2 K, yielding the 1311owing results; $H_{hf}=146.0kOe,\;{\Delta}E_Q=1.88mm/s,\;\theta=36^{\circ},\;\phi=0^{\circ},\;\eta=0.6$, and R=1.9. The Ga ions enter into the both sites octahedral (B) and tetrahedral (A), simultaneously the same amounts of Fe ions migrate from the A to the B site, this result is an agreement with XRD results, too. The ${\Delta}E_Q$ of the A and B site in Mossbauer spectra of the samples $FeCr_{2-x}Ga_xS_4$(x=0.3) are 0.83 and 2.94mm/s, respectively. While they are 0.56 and 2.36mm/s for the $FeCr_{2-x}In_xS_4$(x=0.3). It is noticeable that the ${\Delta}E_Q$ for the Ga doped samples are larger than that of the corresponding In doped samples, in spite of the larger ionic radius for In ions. The bond lengths of Cr-S, for the Ga and In doped samples (x=0.3) are found to be 2.41 and $2.43\;{\AA}$, respectively. We interpret that the larger covalence effect from the smaller bond length induces a large asymmetric charge distribution. Finally, it gives a large quadrupole interaction.

    Study of Mg2Ni1-xFex Alloys by Mössbauer Resonance (Mössbauer 공명에 의한 Mg2Ni1-xFex 합금의 연구)

    • Song, MyoungYoup
      • Transactions of the Korean hydrogen and new energy society
      • /
      • v.10 no.2
      • /
      • pp.119-130
      • /
      • 1999
    • After preparing $Mg_2Ni_{1-x}{^{57}}Fe_x$(x=0.015, 0.03, 0.06, 0.12 and 0.24) alloys, they were studied by $M{\ddot{o}}ssbauer$ resonance. The $M{\ddot{o}}ssbauer$ spectra of x=0.015 and 0.03 alloys exhibit two doublets (doublet 1, 2). That of x=0.06 alloys shows two doublets (doublet 1,2) and one six-line, and those of x=0.12 and 0.24 alloys have only one six-line. The doublet 1 for x=0.015, 0.03 and 0.06 alloys is considered to result from a fraction of Fe in excess showing a superparamagnetic behavior. The doublet 2 is considered to result from the Fe substituted for Ni in the $Mg_2Ni$ phase. The values of isomer shift 0.24 ~ 0.28 mm/s suggest that the iron exist in the state $Fe^{+3}$. The result that the quadrapole splitting of the doublet 2 is not zero shows that the distribution of electrons around the iron is asymmetric. Their values for the doublet 2, 1.20 ~ 1.38 mm/s, approach the value of quadrapole for the oxidation number +3. The six-line showing the magnetic hyperfine interactions results from the iron which has not substituted the nickel in the $Mg_2Ni$ phase. The $M{\ddot{o}}ssbauer$ spectra of the hydrided alloys with x=0.015 and 0.03 show six-line. This suggests that the iron segregates with the hydriding reaction. The analysis results of the $M{\ddot{o}}ssbauer$ spectrum, the variation of magnetization with magnetic field, Auger electron spectroscopy and electron diffraction show the segregation of Ni and the formation of MgO. This is considered to result from the reaction of the $Mg_2Ni$ phase with the oxygen contained in the hydrogen as impurity.

    • PDF

    (34141) Korea Institute of Science and Technology Information, 245, Daehak-ro, Yuseong-gu, Daejeon
    Copyright (C) KISTI. All Rights Reserved.