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Techno-Economic Analysis of Reversible Solid Oxide Fuel Cell System Couple with Waste Steam (폐스팀을 이용한 가역 고체산화물 연료전지의 기술적 경제적 해석)

  • GIAP, VAN-TIEN;LEE, YOUNG DUK;KIM, YOUNG SANG;AHN, KOOK YOUNG
    • Journal of Hydrogen and New Energy
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    • v.30 no.1
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    • pp.21-28
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    • 2019
  • Reversible solid oxide fuel cell (ReSOC) system was integrated with waste steam for electrical energy storage in distributed energy storage application. Waste steam was utilized as external heat in SOEC mode for higher hydrogen production efficiency. Three system configurations were analyzed to evaluate techno-economic performance. The first system is a simple configuration to minimize the cost of balance of plant. The second system is the more complicated configuration with heat recovery steam generator (HRSG). The third system is featured with HRSG and fuel recirculation by blower. Lumped models were used for system performance analyses. The ReSOC stack was characterized by applying area specific resistance value at fixed operating pressure and temperature. In economical assessment, the levelized costs of energy storage (LCOS) were calculated for three system configurations based on capital investment. The system lifetime was assumed 20 years with ReSOC stack replaced every 5 years, inflation rate of 2%, and capacity factor of 80%. The results showed that the exergy round-trip efficiency of system 1, 2, 3 were 47.9%, 48.8%, and 52.8% respectively. The high round-trip efficiency of third system compared to others is attributed to the remarkable reduction in steam requirement and hydrogen compression power owning to fuel recirculation. The result from economic calculation showed that the LCOS values of system 1, 2, 3 were 3.46 ¢/kWh, 3.43 ¢/kWh, and 3.14 ¢/kWh, respectively. Even though the systems 2 and 3 have expensive HRSG, they showed higher round-trip efficiencies and significant reduction in boiler and hydrogen compressor cost.

Metabolizable energy requirement for maintenance estimated by regression analysis of body weight gain or metabolizable energy intake in growing pigs

  • Liu, Hu;Chen, Yifan;Li, Zhongchao;Li, Yakui;Lai, Changhua;Piao, Xiangshu;van Milgen, Jaap;Wang, Fenglai
    • Asian-Australasian Journal of Animal Sciences
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    • v.32 no.9
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    • pp.1397-1406
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    • 2019
  • Objective: Feed energy required for pigs is first prioritized to meet maintenance costs. Additional energy intake in excess of the energy requirement for maintenance is retained as protein and fat in the body, leading to weight gain. The objective of this study was to estimate the metabolizable energy requirements for maintenance ($ME_m$) by regressing body weight (BW) gain against metabolizable energy intake (MEI) in growing pigs. Methods: Thirty-six growing pigs ($26.3{\pm}1.7kg$) were allotted to 1 of 6 treatments with 6 replicates per treatment in a randomized complete block design. Treatments were 6 feeding levels which were calculated as 50%, 60%, 70%, 80%, 90%, or 100% of the estimated ad libitum MEI ($2,400kJ/kg\;BW^{0.60}\;d$). All pigs were individually housed in metabolism crates for 30 d and weighed every 5 d. Moreover, each pig from each treatment was placed in the open-circuit respiration chambers to measure heat production (HP) and energy retained as protein ($RE_p$) and fat ($RE_f$) every 5 d. Serum biochemical parameters of pigs were analyzed at the end of the experiment. Results: The average daily gain (ADG) and HP as well as the $RE_p$ and $RE_f$ linearly increased with increasing feed intake (p<0.010). ${\beta}$-hydroxybutyrate concentration of serum tended to increase with increasing feed intake (p = 0.080). The regression equations of MEI on ADG were MEI, $kJ/kg\;BW^{0.60}\;d=1.88{\times}ADG$, g/d+782 ($R^2=0.86$) and $ME_m$ was estimated at $782kJ/kg\;BW^{0.60}\;d$. Protein retention of growing pigs would be positive while REf would be negative at this feeding level via regression equations of $RE_p$ and $RE_f$ on MEI. Conclusion: The $ME_m$ was estimated at $782kJ/kg\;BW^{0.60}\;d$ in current experiment. Furthermore, growing pigs will deposit protein and oxidize fat if provided feed at the estimated maintenance level.

How are Good Dogs Made? : Focusing on the Cultural Intermediary Work of Dog Trainers in EBS1 and KBS2 (좋은 반려견은 어떻게 만들어지는가? : EBS1 <세상에 나쁜 개는 없다>와 KBS2 <개는 훌륭하다>의 반려견 훈련사의 문화매개 작업을 중심으로)

  • Choo, Hye-Won
    • Journal of Korea Entertainment Industry Association
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    • v.14 no.4
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    • pp.17-29
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    • 2020
  • This research looked into the two programs There are No Bad Dogs in the World(EBS1) and The Dogs are Respectable(KBS2) that can be considered as one of the factors that changed the culture of dog rearing in the country. Focus was also directed toward the cultural intermediary work of trainer Hyung-Wook Kang and veterinarian Chae-Hyun Seol, and the linguistic texts and visual images that describe the programs were analyzed. The findings showed that the two experts reproduce dog-related beliefs and values using devices such as "serious" storytelling, dog bodies, and guardian re-education. They perform cultural intermediary work in that they create the value of the companion dog culture in these programs and provide corresponding products and services to consumers through direct face-to-face interactions. This study contributes academically in the following respects. First, the issue of companion dogs in Korea was approached from a cultural point of view rather than bounding analysis to the industrial and economic level called the "petconomy" (pet + economy). Second, the concept of cultural intermediaries and related theories were examined, along with how the two experts engender the value of dog training in the broadcasting program. The results are expected to help illustrate the diversity of Korean dog culture.

Die Organisation von Mikrostrukturen der zweisprachigen $W\"{o}rterb\"{u}cher$ Deutsch/Koreanisch (독-한 두말사전의 미시구조 조직)

  • Kim Kyong
    • Koreanishche Zeitschrift fur Deutsche Sprachwissenschaft
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    • v.5
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    • pp.183-202
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    • 2002
  • Die vorliegende Arbeit verfolgt zwei Ziele: zum einen sollen die Entwicklungen in der modernen zweisprachigen Lexikographie mit Ausgangssprache Deutsch skizzenhaft vorgestellt und einige Forschungsdefizite benannt werden, zum anderen sollen die Ergebnisse und Methoden der neueren Lexikographie anhand von Beispielartikeln der drei $einschl\"{a}gigen$ deutsch-koreanischen $Gro{\ss}w\"{o}rterblicher$ kontrastiert und diskutiert werden. Zuerst wird eine Typologie der zweisprachigen $W\"{o}rterb\"{u}cher$ erstellt, derzufolge es jeweils 2 aktive und 2 passive Worterblicher pro Sprachenpaar gibt. Das Aktiv-Passiv­Prinzip gilt als ein grundlegender Ausgangspunkt $f\"{u}r$ die zweisprachige Lexikographie. Eine Erweiterung der Unterscheidungskriterien scheint nicht $zweckm\"{a}{\ss}ig$ und angesichts praktischer Schwierigkeiten auch kaum realisierbar. $Pl\"{a}diert\;wird\;f\"{u}r\;eine\;st\"{a}rkere\;Ber\"{u}cksichtigung$ der Benutzungssituationen, zu denen z.B. der Grad der Sprachbeherr­schung der jeweiligen Benutzergruppe, die $m\"{o}glichen\;Benutzungsanl\"{a}sse$, der Kenntnisstand $bez\"{u}glich$ der Benutzerhinweise sowie die technische Geschicklichkeit bei der $W\"{o}rterbuch-benutzung\;etc.\;zu\;z\"{a}hlen$ sind. In makrostruktueller Hinsicht werden die Selektion und die Anordnung der Lemmata diskutiert. Bei der Lemmaauswahl $w\"{a}re\;es\;w\"{u}nschenswert$, auf der Grundlage eines Lemmavergleiches der verschiedensten Quellenworterbucher ein datenbasiertes Korpus zu erstellen. Dazu $k\"{o}nnten$ folgende Materialien ausgewertet werden: (1) einsprachige allgemeine (ad spezielle) $W\"{o}rterb\"{u}cher$ (z.B. Deutsch/Koreanisch), (2) zweisprachige allgemeine (od spezielle) Worterblicher (z.B. Deutsch-Koreanisch, Deutsch-Englisch) etc. Die $blo{\ss}e\;\"{U}bersetzung$ lediglich eines einzigen $Quellenw\"{o}rterbuches\;k\"{o}nnte$ dagegen zu $unerw\"{u}nschten\;Einseitigkeiten\;f\"{u}hren$. Was die Anordnung der Lemmata in zweisprachigen $W\"{o}rterb\"{u}chern$ betrifft, $k\"{o}nnen$ dieselben drei makrostrukturellen Typen unterschieden werden, wie in einsprachigen $W\"{o}rterb\"{u}chern$: (1) glattalphabetisch, (2) nischenalphabetisch, (3) nestalphabetisch. Unter den zu untersuchenden $W\"{o}rterb\"{u}chern$ weisen das EDK und das HDK die nischenalpha­betische Makrostruktur auf, das MDK ist dagegen nestalphabetisch angeordnet. Je nachdem, wie die Polysemiestruktur und die Mehr-Wort-Einheit kombinieren, werden die drei Arten der Mikrostruktur unterschieden: (1) die integrierte Mikrostruktur, (2) die nichtintegrierte Mikrostruktur, (3) die partiell integrierte Mikrostruktur. $W\"{a}hrend$ das EDK und das HDKeine integrierte Mikrostruktur besitzen, weist das HDK eine partiell integrierte Mikrostruktur auf. Die Artikelgestaltung durch die nichtintegrierte Mikrostruktur, die $h\"{a}ufig$ in der zweisprachigen Lexikographie angewandt wird und entsprechende Vorteile besitzt, sallte $k\"{u}nftig\;als\;Gestaltungsm\"{o}glichkeit\;st\"{a}rker$in Betracht gezogen werden. In Bezug auf die Organisation der Mikrostruktur werden vier Bauteile, das sind Lemma-, $\"{A}quivalent-$, Diskriminator- und Beispielangaben untersucht. Die $\"{U}bersetzungs\"{a}quivalente$ werden je nach dem lexikalisch-semantischen Abdeckungsgrad mit dem Lemma in drei Typen eingeteilt: (1) $Voll\"{a}quivalent,\;(2)\;Teil\"{a}quivalent,\;(3)\;Null\"{a}quivalent$. In der Mehrheit kommen die Teil- oder $Null\"{a}quivalente$ vor, weil die ausgangssprachlichen Lemmata und die zielsprachlichen $\"{A}quivalente$ in sich Polysemiestruktur aufweisen. $Informationsm\"{a}ngel$ auszugleichen ist die Funktion des Diskriminators, in dem Glosse, Markierungen und metasprachliche $Erl\"{a}uterungen$ zusammenwirken. $Verbesserungsw\"{u}rdig\;sind\;die\;g\"{a}ngigen$ deutsch-koreanischen $W\"{o}rterb\"{u}cher$ var allem im Hinblick auf die stilistischen Markierungen; die Inkongruenz des Stils zwischen den beiden verschiedenen Sprachen wird bislang zu wenig $ber\"{u}cksichtigt$ und sagar in ein und demselben $W\"{o}rterbuch$ nicht konsequent dargestellt. Trotz der relativen $Geringsch\"{a}tzung$ von Beispielangaben in der $europ\"{a}ischen$ zweisprachigen passiven Lexikographie sallte diesen in deutsch-koreanischen $W\"{o}rterb\"{u}chern$ mehr Aufmerksamkeit gewidrnet werden. Sie sind dem koreanischen Benutzer eine wichtige Hilfe, indem sie die $\"{A}quivalentenangaben\;implizite\;erg\"{a}nzen$ und Informationen $\"{u}ber$ die syntaktisch-semantische und pragmatische Kontextrestriktion bieten. $Dar\"{u}berhinaus$ stellen sie selbst interessante kulturelle, geistige und landeskundliche etc. Informationen dar. Was den Artikelaufbau betrifft, wird das Van Dale-Modell diskutiert, d.h. das kategoriell-semantisch-alphabetische Prinzip, das trotz mancher Kritikpunkte viele interessante Anregungen $f\"{u}r$ die zweisprachige Lexikographie Deutsch-Koreanisch bietet, wo z.B. noch nicht die $Pr\"{a}positionen$ in der Beispielangabe durch typographische Hervorhebung $pr\"{a}sentiert$ worden sind. Aus $Platzgr\"{u}nden$ sind hier nur wenige Beispielartikel mit substantivischen Lemmata $angef\"{u}hrt$ und analysiert worden. Um die $h\"{o}here$ Generalisierbarkeit zu erreichen, brauchen die Untersuchungs- materialien mindestens einen bestimmten Umfang. Derartige empirische Forschungen $k\"{o}nnen$ als Impulse dazu beitragen, $k\"{u}nftige\;W\"{o}rterb\"{u}cher$ im Sinne einer $Ber\"{u}cksichtigung$ neuerer lexikographischer Erkenntnisse verbessern zu helfen.

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High quality topological insulator Bi2Se3 grown on h-BN using molecular beam epitaxy

  • Park, Joon Young;Lee, Gil-Ho;Jo, Janghyun;Cheng, Austin K.;Yoon, Hosang;Watanabe, Kenji;Taniguchi, Takashi;Kim, Miyoung;Kim, Philip;Yi, Gyu-Chul
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.284-284
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    • 2016
  • Topological insulator (TI) is a bulk-insulating material with topologically protected Dirac surface states in the band gap. In particular, $Bi_2Se_3$ attracted great attention as a model three-dimensional TI due to its simple electronic structure of the surface states in a relatively large band gap (~0.3 eV). However, experimental efforts using $Bi_2Se_3$ have been difficult due to the abundance of structural defects, which frequently results in the bulk conduction being dominant over the surface conduction in transport due to the bulk doping effects of the defect sites. One promising approach in avoiding this problem is to reduce the structural defects by heteroepitaxially grow $Bi_2Se_3$ on a substrate with a compatible lattice structure, while also preventing surface degradation by encapsulating the pristine interface between $Bi_2Se_3$ and the substrate in a clean growth environment. A particularly promising choice of substrate for the heteroepitaxial growth is hexagonal boron nitride (h-BN), which has the same two-dimensional (2D) van der Waals (vdW) layered structure and hexagonal lattice symmetry as $Bi_2Se_3$. Moreover, since h-BN is a dielectric insulator with a large bandgap energy of 5.97 eV and chemically inert surfaces, it is well suited as a substrate for high mobility electronic transport studies of vdW material systems. Here we report the heteroepitaxial growth and characterization of high quality topological insulator $Bi_2Se_3$ thin films prepared on h-BN layers. Especially, we used molecular beam epitaxy to achieve high quality TI thin films with extremely low defect concentrations and an ideal interface between the films and substrates. To optimize the morphology and microstructural quality of the films, a two-step growth was performed on h-BN layers transferred on transmission electron microscopy (TEM) compatible substrates. The resulting $Bi_2Se_3$ thin films were highly crystalline with atomically smooth terraces over a large area, and the $Bi_2Se_3$ and h-BN exhibited a clear heteroepitaxial relationship with an atomically abrupt and clean interface, as examined by high-resolution TEM. Magnetotransport characterizations revealed that this interface supports a high quality topological surface state devoid of bulk contribution, as evidenced by Hall, Shubnikov-de Haas, and weak anti-localization measurements. We believe that the experimental scheme demonstrated in this talk can serve as a promising method for the preparation of high quality TI thin films as well as many other heterostructures based on 2D vdW layered materials.

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쌍끌이 중층트롤어법의 연구 ( 1 ) - 모형어구의 망구형상에 관하여 - ( A Study on the Pair Midwater Trawling ( 1 ) - Mouth Performance of the Model Net - )

  • 이병기
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.31 no.1
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    • pp.29-44
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    • 1995
  • A model experiment on the pair midwater trawl net applicable to 800 PS class Korean pair bottom trawlers was carried out in the special-prepared experimental thank. the tank was prepared as a reverse trapezoid shape in its vertical section by digging out flat soil. The dimension of the tank showed the 9.6 W$\times$43.0 L(m) of the upper fringe and the 4.8 W$\times$38.0 L(m) of the bottom with 3.0m in depth. The depth of water was maintained 2.7m during experiment. The model net was prepared based on the Tauti's similarity law of fishing gear in 1/30 scale considering the dimension of the experimental tank. Mouth performance of the model net during towing were determined by the photographs taken in front of the net mouth with the combinations of towing velocity, warp length and distance between paired boats. The results obtained can be summarized as follows: 1. Vertical opening of the model nets A and B was varied in the range of 0.18~0.88 m and 0.21~0.78 m (which can be converted into 5.4~26.4m and 6.3~23.4 m in the full-scale net) respectively, and was varied predominantly by towing speed. Vertical opening (H which is appendixed m for the model net. f for the full-scale net. A and B for the types of the model net) can be expressed as the function of towing velocity$V_t$as in the model net $V_t$ : m/ sec)$H_{mA}$=1.67$e^{-1.65V_t}$ $H_{mB}$=1.15$e^{-1.13V_t}$, in the full-scale net ($V_t$ : k't) $H_{fA}$=50.27$e^-0.37V_t$ $H_{fB}$=34.46$e^{-0.26Vt}$. 2. Horizontal opening of the model nets An and b was varied in the range of 1.03~1.54m and 1.04~1.55 m (which can be converted into 30.9~46.2 m and 31.2~46.5m in the full-scale net) respectively, and was varied predominantly by distance between paired boats. Horizontal opening (W, appendixes are as same as the former) an be expressed as the function of distance between paired boats $D_b$as in the model net $W_{mA}$=0.69+0.09$D_b$ $W{mB}$=0.73+0.09$D_b$, in the full-scale net $W_{fA}$=20.81+0.09$D_b$ $W_{fB}$=22.11+0.09$D_b$ 3. Net opening area of the model net A and B was varied in the range of 0.28~1.04 $m^2$ and 0.33~0.94$m^2$(which can be converted into 252~936$m^2$ and 297~846$m^2$ in the full-scale net) respectively, and was varied predominantly by towing velocity. Net opening area ($S$, appendixes are as same as the former) van be expressed as the function of towing velocity$V_t$ as in the model net $v_t$ : m/sec) $S_{Ma}$=2.01$e^{-1.54V_T}$ $S_{mA}$=1.40$e^{-1.65V_t}$, in the full-scale net ($V_t$ : k't) $S_{fA}$=1.807$e^-0.35V_t$ $S_{fA}$=1.265$e^{-0.24V_t}$. 4. Filtering volume of the model nets A and B was varied in the range of 0.32~0.55 $m^3$ and 0.37~0.55$m^3$(which can be converted into 8.640~14.850 $m^3$ and 9.990~14.850$m3$in the full~scale net) respectively, and was predominantly varied by towing speed. filtering volume of the model net-A showed the maximum at the towing speed 0.69 m/sec(3 k't in the full-scale net), compared with that of the model net B showed at 0.92 m/sec(4 k't in the full-scale net).

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Effects of a Blend of Prunus Mume Extract as an Alternative to Antibiotics on Growth Performance, Activity of Digestive Enzymes and Microflora Population in Broiler Chickens (항생제 대체 사료첨가제로서 매실추출 혼합물이 육계의 성장, 소화 효소 활성도 및 장내 미생물 균총에 미치는 영향)

  • Ko, Y.H.;Yang, H.Y.;Kang, S.Y.;Kim, E.S.;Jang, I.S.
    • Journal of Animal Science and Technology
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    • v.49 no.5
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    • pp.611-620
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    • 2007
  • The current study was designed to define whether a blend of prunus mume extract(25%) containing lactic acid(75%) and grape seed extract(10ppm) could affect in vitro antimicrobial activity and growth performance, intestinal microflora, plasma biochemical profiles and digestive enzymes activities in broiler chickens. In paper disc agar diffusion test, we clearly observed antimicrobial activity against E. coli in response to prunus mume extract or a blend of prunus mume extract. For in vivo test, a total of ninety six 3-d-old male broiler chicks were assigned to basal diet(CON), basal diet supplemented with antibiotics (ANTI) and 0.5% a blend of prunus mume extract(PRNUS) until 35 days of age. Throughout the entire experimental period(3-35 days), there were no differences in BW and FCR between the birds fed the basal diet with antibiotics and the diet supplemented with a blend of prunus mume. However, ANTI group showed a significant increase in BW and total gain compared to CON group. The weights of digestive organs such as the pancreas and mucosal tissues were not affected by dietary treatments. There was no difference in plasma levels of glucose, cholesterol, AST and ALT activity. However, triglyceride in plasma increased(P<0.05) in the birds fed the diet supplemented with 0.5% a blend of prunus mume extract compared to those fed antibiotics supplemented diet. The activities of pancreatic trypsin and amylase, and intestinal hydrolase including disaccharidase were not affected by dietary treatment. The colony forming units(CFU) of lactobacillus in the lower ileal-cecum of the birds fed the diet supplemented with a blend of prunus mume extract was significantly(P<0.05) higher than that of birds fed antibiotic supplemented diet without affecting the CFU of E. coli. In conclusion, the birds fed the diet supplemented a blend of prunus mume as an alternative to antibiotics showed a similar growth performance and an significant increase in lactobacillus population compared with the birds fed basal and antibiotics supplemented diets.

A PLS Path Modeling Approach on the Cause-and-Effect Relationships among BSC Critical Success Factors for IT Organizations (PLS 경로모형을 이용한 IT 조직의 BSC 성공요인간의 인과관계 분석)

  • Lee, Jung-Hoon;Shin, Taek-Soo;Lim, Jong-Ho
    • Asia pacific journal of information systems
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    • v.17 no.4
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    • pp.207-228
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    • 2007
  • Measuring Information Technology(IT) organizations' activities have been limited to mainly measure financial indicators for a long time. However, according to the multifarious functions of Information System, a number of researches have been done for the new trends on measurement methodologies that come with financial measurement as well as new measurement methods. Especially, the researches on IT Balanced Scorecard(BSC), concept from BSC measuring IT activities have been done as well in recent years. BSC provides more advantages than only integration of non-financial measures in a performance measurement system. The core of BSC rests on the cause-and-effect relationships between measures to allow prediction of value chain performance measures to allow prediction of value chain performance measures, communication, and realization of the corporate strategy and incentive controlled actions. More recently, BSC proponents have focused on the need to tie measures together into a causal chain of performance, and to test the validity of these hypothesized effects to guide the development of strategy. Kaplan and Norton[2001] argue that one of the primary benefits of the balanced scorecard is its use in gauging the success of strategy. Norreklit[2000] insist that the cause-and-effect chain is central to the balanced scorecard. The cause-and-effect chain is also central to the IT BSC. However, prior researches on relationship between information system and enterprise strategies as well as connection between various IT performance measurement indicators are not so much studied. Ittner et al.[2003] report that 77% of all surveyed companies with an implemented BSC place no or only little interest on soundly modeled cause-and-effect relationships despite of the importance of cause-and-effect chains as an integral part of BSC. This shortcoming can be explained with one theoretical and one practical reason[Blumenberg and Hinz, 2006]. From a theoretical point of view, causalities within the BSC method and their application are only vaguely described by Kaplan and Norton. From a practical consideration, modeling corporate causalities is a complex task due to tedious data acquisition and following reliability maintenance. However, cause-and effect relationships are an essential part of BSCs because they differentiate performance measurement systems like BSCs from simple key performance indicator(KPI) lists. KPI lists present an ad-hoc collection of measures to managers but do not allow for a comprehensive view on corporate performance. Instead, performance measurement system like BSCs tries to model the relationships of the underlying value chain in cause-and-effect relationships. Therefore, to overcome the deficiencies of causal modeling in IT BSC, sound and robust causal modeling approaches are required in theory as well as in practice for offering a solution. The propose of this study is to suggest critical success factors(CSFs) and KPIs for measuring performance for IT organizations and empirically validate the casual relationships between those CSFs. For this purpose, we define four perspectives of BSC for IT organizations according to Van Grembergen's study[2000] as follows. The Future Orientation perspective represents the human and technology resources needed by IT to deliver its services. The Operational Excellence perspective represents the IT processes employed to develop and deliver the applications. The User Orientation perspective represents the user evaluation of IT. The Business Contribution perspective captures the business value of the IT investments. Each of these perspectives has to be translated into corresponding metrics and measures that assess the current situations. This study suggests 12 CSFs for IT BSC based on the previous IT BSC's studies and COBIT 4.1. These CSFs consist of 51 KPIs. We defines the cause-and-effect relationships among BSC CSFs for IT Organizations as follows. The Future Orientation perspective will have positive effects on the Operational Excellence perspective. Then the Operational Excellence perspective will have positive effects on the User Orientation perspective. Finally, the User Orientation perspective will have positive effects on the Business Contribution perspective. This research tests the validity of these hypothesized casual effects and the sub-hypothesized causal relationships. For the purpose, we used the Partial Least Squares approach to Structural Equation Modeling(or PLS Path Modeling) for analyzing multiple IT BSC CSFs. The PLS path modeling has special abilities that make it more appropriate than other techniques, such as multiple regression and LISREL, when analyzing small sample sizes. Recently the use of PLS path modeling has been gaining interests and use among IS researchers in recent years because of its ability to model latent constructs under conditions of nonormality and with small to medium sample sizes(Chin et al., 2003). The empirical results of our study using PLS path modeling show that the casual effects in IT BSC significantly exist partially in our hypotheses.

Optimal Spatial Scale for Land Use Change Modelling : A Case Study in a Savanna Landscape in Northern Ghana (지표피복변화 연구에서 최적의 공간스케일의 문제 : 가나 북부지역의 사바나 지역을 사례로)

  • Nick van de Giesen;Paul L. G. Vlek;Park Soo Jin
    • Journal of the Korean Geographical Society
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    • v.40 no.2 s.107
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    • pp.221-241
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    • 2005
  • Land Use and Land Cover Changes (LUCC) occur over a wide range of space and time scales, and involve complex natural, socio-economic, and institutional processes. Therefore, modelling and predicting LUCC demands an understanding of how various measured properties behave when considered at different scales. Understanding spatial and temporal variability of driving forces and constraints on LUCC is central to understanding the scaling issues. This paper aims to 1) assess the heterogeneity of land cover change processes over the landscape in northern Ghana, where intensification of agricultural activities has been the dominant land cover change process during the past 15 years, 2) characterise dominant land cover change mechanisms for various spatial scales, and 3) identify the optimal spatial scale for LUCC modelling in a savanna landscape. A multivariate statistical method was first applied to identify land cover change intensity (LCCI), using four time-sequenced NDVI images derived from LANDSAT scenes. Three proxy land use change predictors: distance from roads, distance from surface water bodies, and a terrain characterisation index, were regressed against the LCCI using a multi-scale hierarchical adaptive model to identify scale dependency and spatial heterogeneity of LUCC processes. High spatial associations between the LCCI and land use change predictors were mostly limited to moving windows smaller than 10$\times$10km. With increasing window size, LUCC processes within the window tend to be too diverse to establish clear trends, because changes in one part of the window are compensated elsewhere. This results in a reduced correlation between LCCI and land use change predictors at a coarser spatial extent. The spatial coverage of 5-l0km is incidentally equivalent to a village or community area in the study region. In order to reduce spatial variability of land use change processes for regional or national level LUCC modelling, we suggest that the village level is the optimal spatial investigation unit in this savanna landscape.

Chemical Structures and Physiological Activities of Plant Growth Substance, Malformin B's (식물생장조절물질 말포민 B동족체의 화학구조 및 생리활성)

  • Kim, K.W.
    • Korean Journal of Weed Science
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    • v.15 no.1
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    • pp.85-98
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    • 1995
  • Six malformin B's produced by Aspergillus niger van Tiegh. were separated by HPLC. Their structures determined by the methods of amino acid analyses, mass spectrometry, and two-dimensional NMR were revealed as cyclic pentapeptides structurally related to malformin $A_1$. Both the NMR and MS/MS data suggest that the respective structures of separated malformin B's were as follows; cyclo-D-Cys-D-Cys-L-Val-D-Leu-L-allo-Ile for $B_{1a}$, cyclo-D-Cys-D-Cys-L-Val-D-Leu-L-Leu for $B_{1b}$, cyclo-D-Cys-D-Cys-L-Val-D-Val-L-Leu for $B_2$, cyclo-D-Cys-D-Cys-L-Val-D-Ile-L-Leu for $B_3$, cyclo-D-Cys-D-Cys-L-Val-D-Ile-L-Ile for $B_4$, and cyclo-D-Cys-D-Cys-L-Val-D-Val-L-Ile for $B_5$. Among the malformin B's, the structure of $B_{1b}$ was the same as that of malformin $A_3$ or C. All the malformin B's showed physiological activities in the two assay systems using corn(Zea mays L.) roots and mung bean(Phaseolus aureus Roxb.) hypercotyl segments. The malformin B's with molecular weight 529 were more effective for inducing corn root curvature than those with molecular weight 515. The difference in molecular weight of malformin B's, i.e., the retention time on HPLC, results in the polarity change of the whole malformin molecule which affects the revealation of the malformin activities. In addition, the disulfide form of the malformin B's gives the rigidity of the molecule, whereas the combination of the fourth and the fifth amino acid residues provides the optimal three-dimensional configuration to the malformin receptor of plants. Presumably, these two factors are appeared to be essential for the greatest physiological activity of malformin B's. malformin $B_{1a}$ caused the corn root curvature by 90% at a concentration of $0.25{\mu}M$. However, such differential activities with molecular weight of 529 or 515 of malformin B's were not found in the mung bean hypercotyl segment test. Maximum stimulation of mung bean hypercotyl growth was observed at $0.1{\mu}M$ concentration of malformin B's. The growth of the segments treated with $B_5$ was 154% greater than that of the control.

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