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Monitoring with Parametrized Extended Life Sequence Charts

Chai M., Schlingloff B. -H.

Fundamenta Informaticae

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2017

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Vol. 153, nr 3

173--198

EN

Runtime verification is a lightweight formal method that checks whether an execution of a system satisfies a given property. A challenge in building a runtime verification system is to define a suitable monitoring specification language, i.e., a language that is expressive, of reasonable complexity, and easy to understand. In this paper, we extend live sequence charts (LSCs, [1]) for the specification of properties in systems monitoring. We define Parametrized extended LSCs (PeLSCs) by introducing the notions of necessary prechart, concatenation, and conditionand assignment-structure. With these PeLSCs, necessary and sufficient conditions of certain observations, and parametric properties can be specified in an intuitive way. We prove some results about the expressiveness of extended LSCs. In particular, we show that LSCs with necessary precharts are strictly more expressive than standard LSCs, and that iteration-free extended LSCs have the same expressive power as linear temporal logic (LTL). To generate monitors, we develop translations of PeLSCs into hybrid logic. We show that the complexity of the word problem of PeLSCs is linear with respect to the length of input traces, thus our formalism is well-suited for online monitoring of communicating systems.

2

Effects of saline-alkaline stress on early growth strategy and colonization success of Flaveria bidentis ( L.) Kuntze (Asteraceae ) - a new exotic plant in Northern China

Chai M., Shi F., He K., Li R., Cao D., He Z.

Polish Journal of Ecology

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2012

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Vol. 60, nr 3

559-565

EN

Flaveria bidentis, an annual grass native to South America, has invaded into many countries all over the world, including South Africa and Egypt in Africa, Britain and France in Europe, Japan in Asia, and Australia. In China, this plant species has been widely distributed in Hebei province since 2001 of its first discovery in Tianjin. In salinized soil of northern China, F. bidentis has formed mono dominant communities owing to its opportunistic characteristics. In this study, we investigated germination rate, germination energy, germination index and vigor index in response to different saline-alkaline stresses. Lengths of seedling, hypocotyl, and radicle were also examined. During germination process, germination rate, germination energy, germination index, and vigor index decreased due to higher salinity and alkalinity (pH). Hypocotyl elongation was stimulated at low salinity and alkalinity, but decreased with increasing salinity and alkalinity. The lengths of radicle and seedling were inhibited sharply with increasing salinity and alkalinity. These results suggest that a reciprocal enhancement between salt stress and alkaline stress was a characteristic feature during seed germination of F. bidentis. Ungerminated seeds resumed to germinate after transferred to distilled water, indicating that seeds remained viable during their exposure to saline-alkaline stresses. Stepwise regression analysis indicated that the effects of salinity, alkalinity (pH), and buffer capacity on seed germination and seedling growth were significantly different in magnitude. Salinity and alkalinity (pH) were the dominant factors in seed germination and seedling growth of F. bidentis respectively. Further, the results of this study suggest that F. bidentis has developed excellent adaptative strategy in its early stage of life cycle which partially explains its current invasion success in northern China.

3

Determination of the impurities in high purity rubidium chloride

Jiang Y., Gao S., Hu M., Fang Q., Xia S., Chai M.

Chemia Analityczna

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2003

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Vol. 48, No. 1

37-44

EN

Alkali metal elements often occur together, and their separation and simultaneous determination is not an easy task. In this paper, a very simple, sensitive and reliable method is presented for the determination of the trace impurities of alkali metal ions (lithium, sodium, potassium and cesium) in high purity rubidium chloride by flame atomic absorption spec-trometry (FAAS). The detection limit which was expressed in characteristic concentration (ug mL(-1) /1 % absorption) for Li+, Na+, K+, Cs+ was 0.032, 0.011, 0.034 and 0.183 respectively, and the recovery in the spiked samples was in the range : 91.6% ~ 107.8%. The analytical system can be used conveniently to monitor the product quality of RbCl in the process of its preparation and purification. In addition, the procedure could be adopted for the analysis of other similar samples.

PL

Metale alkaliczne często występują razem a ich rozdzielanie i jednoczesne oznaczanie jest niełatwym zadaniem. W niniejszej pracy przedstawiono prostą, czulą i wiarygodną metodę oznaczania śladowych ilości metali alkalicznych w chlorku rubidu wysokiej czystości za pomocą płomieniowej absorpcyjnej spektrometrii atomowej (FAAS). Granice detekcji wyrażone jako charakterystyczne stężenie (fig mL(-1)/1 % absorpcji) dla Li+, Na+, K+, Cs+ wynosiły odpowiednio: 0.032,0.011,0.034 i 0.183, a odzysk w próbkach ze znanym dodatkiem metali alkalicznych był w granicach 91.6-107.8%. Ten układ analityczny dobrze nadaje się do monitorowania jakości RbCl w procesie jego otrzymywania i oczyszczania. Poza tym ten sposób postępowania może być zaadaptowana do analizy innych, podobnych produktów.