Understanding the Roles of Convective Trigger Functions in the Diurnal Cycle of Precipitation in the NCAR CAM5

The wrong diurnal cycle of precipitation is a common weakness of current global climate models (GCMs). To improve the simulation of the diurnal cycle of precipitation and understand what physical processes control it, we test a convective trigger function described in Xie et al. (2019) with additional optimizations in the NCAR Community Atmosphere Model version 5 (CAM5). The revised trigger function consists of three modifications: 1) replacing the Convective Available Potential Energy (CAPE) trigger with a dynamic CAPE (dCAPE) trigger, 2) allowing convection to originate above the top of planetary boundary layer (i.e., the unrestricted air parcel launch level - ULL), and 3) optimizing the entrainment rate and threshold value of the dynamic CAPE generation rate for convection onset based on observations. Results from 1°-resolution simulations show that the revised trigger can alleviate the long-standing GCM problem of too early maximum precipitation during the day and missing the nocturnal precipitation peak that is observed in many regions, including the US Southern Great Plains (SGP). The revised trigger also improves the simulation of the propagation of precipitation systems downstream of the Rockies and the Amazon region. A further composite analysis over the SGP unravels the mechanisms through which the revised trigger affects convection. Additional sensitivity tests show that both the peak time and the amplitude of the diurnal cycle of precipitation are sensitive to the entrainment rate and dCAPE threshold values.

Consensus of nonlinear multi–agent systems with distributed event–triggered impulsive control

This study addresses the consensus problem in nonlinear multi-agent systems with the distributed impulsive control method. To decrease communication wastage, a distributed event-triggered impulsive protocol is developed to achieve consensus. In the proposed control method, each agent receives neighbor information and performs impulse control only when its own trigger function exceeds a given tolerance. Then, through the Lyapunov method, the conditions that allow the multi-agent systems reach consensus are analyzed and the Zeno behavior is excluded. Finally, some numerical simulations are performed to validate the effectiveness of the proposed method.

A Sensitivity Analysis of Two Mesoscale Models: COAMPS and WRF

A sensitivity analysis methodology recently developed by the authors is applied to COAMPS and WRF. The method involves varying model parameters according to Latin Hypercube Sampling, and developing multivariate multiple regression models that map the model parameters to forecasts over a spatial domain. The regression coefficients and p values testing whether the coefficients are zero serve as measures of sensitivity of forecasts with respect to model parameters. Nine model parameters are selected from COAMPS and WRF, and their impact is examined on nine forecast quantities (water vapor, convective and gridscale precipitation, and air temperature and wind speed at three altitudes). Although the conclusions depend on the model parameters and specific forecast quantities, it is shown that sensitivity to model parameters is often accompanied by nontrivial spatial structure, which itself depends on the underlying forecast model (i.e., COAMPS vs WRF). One specific difference between these models is in their sensitivity with respect to a parameter that controls temperature increments in the Kain–Fritsch trigger function; whereas this parameter has a distinct spatial structure in COAMPS, that structure is completely absent in WRF. The differences between COAMPS and WRF also extend to the quality of the statistical models used to assess sensitivity; specifically, the differences are largest over the waters off the southeastern coast of the United States. The implication of these findings is twofold: not only is the spatial structure of sensitivities different between COAMPS and WRF, the underlying relationship between the model parameters and the forecasts is also different between the two models.

Analisis Keamanan Dalam Desain Database PMB (Penerimaan Mahasiswa Baru) Dengan MySQL

Keamanan dalam desaian suatu database merupakan hal yang sangat penting untuk diterapkan dalam membangun sebuah sistem informasi. Sering kali dalam implementasi keamanan database tidak begitu diperhatikan, baik dari segi tipe data, panjang data, maupun paramter yang berkaitan dengan transaksi data. Kesalahan dalam desain database biasanya baru akan disadari pada saat aplikasi sudah selesai dan sudah digunakan. Untuk memastikan sebuah sistem informasi berjalan dengan lancar maka akan digunakan analisa data berdasarkan rentang data tertinggi dan data terendah. Dengan menggunakan analisa rentang data maka data yang nilainya lebih rendah dari paremeter yang ditentukan akan dirubah ke nilai terendah yang sesuai dengan paramter. Begitu juga data yang nilainya lebih tinggi dari paramter yang telah ditentukan akan dirubah ke nilai tertinggi yang sesuai dengan parameter. Dari hasil pengujian yang dilakukan sebelum adanya filter check dan patameter tipe data dengan memasukan data yang berupa huruf, angka minus serta angka yang melebihi batas atas pada kolom nilai, data masih bisa tersimpan ke database. Pengujian selanjutnya dilakukan dengan memasukan angka -2,-3,-4,-5,-7,-7 serta angka diatas ambang batas atas 12,13,14,15,16,17, dari hasil pengujian yang dilakukan dapat disimpulkan bawah sebuah database dengan fungsi trigger jauh lebih aman dibandingkan dengan database yang hanya menerapkan fungsi pembatasan berdasarkan tipe datanya saja.Kata Kunci —Keamanan Desain Database MySQL, Analisis Keamanan DatabaseSecurity in the design of a database is very important to be applied in building an information system. Often in the implementation of a database security is not given much attention, both in terms of data types, length, and parameters relating to data transactions. Errors in database design are usually only noticed when the application is complete and has been used. To ensure an information system runs well, data analysis will be used based on the highest and lowest data ranges. By using data range analysis, data whose value is lower than the specified parameter will be changed to the lowest value in accordance with the parameters. Data whose value is higher than predetermined parameters will be changed to the highest value in accordance with parameters. Results of tests conducted before the filter check and data type patameter by entering data in the form of letters, minus numbers and numbers that exceed the upper limit in the value column, data can still be saved to database. Further testing is done by entering the numbers -2, -3, -4, -5, -7, -7 and numbers above the upper threshold of 12,13,14,15,16,17, from some of the results of tests conducted can be concluded below a database with a trigger function is more secure than a database that only applies restrictions based on its data type.Keywords— Security Database Design MySQL, Security Analysis Database

Event-Based Formation Control of Multiple Quadrotors on SO(3)

This paper is concerned with the formation problem of multiple quadrotors, and an event-based control strategy is proposed. The communication topology and relative positions of formation are first considered, and then the model of multiple quadrotors system is developed on the special orthogonal group SO(3). By designing the trigger function, certain events are generated for each quadrotor. Then, the formation controller is driven to update its parameters according to the events. The attitude controller on SO(3) is designed for tracking of the command and stabilization. By the proposed method continuous communication is not required between quadrotors, and it is proved that the quadrotors could achieve the desired formation. Simulation illustrates that the proposed event-based formation control method is effective.

A Structurally Unresolved Head Segment of Defined Length Favors Proper Measles Virus Hemagglutinin Tetramerization and Efficient Membrane Fusion Triggering

ABSTRACTParamyxoviruses include several insidious and ubiquitous pathogens of humans and animals, with measles virus (MeV) being a prominent one. The MeV membrane fusion apparatus consists of a receptor binding protein (hemagglutinin [H]) tetramer and a fusion (F) protein trimer. Four globular MeV H heads are connected to a tetrameric stalk through flexible linkers. We sought here to characterize the function of a 17-residue H-head segment proximal to the stalk that was unresolved in all five MeV H-head crystal or cocrystal structures. In particular, we assessed whether its primary sequence and length are critical for proper protein oligomerization and intracellular transport or for membrane fusion triggering. Extensive alanine substitutions had no effect on fusion triggering, suggesting that sequence identity is not critical for this function. Excessive shortening of this segment reduced or completely abrogated fusion trigger function, while length compensation restored it. We then characterized the mechanism of function loss. Mutated H proteins were efficiently transported to the cell surface, but certain alterations enhancing linker flexibility resulted in accumulation of high-molecular-weight H oligomers. Some oligomers had reduced fusion trigger capacity, while others retained this function. Thus, length and rigidity of the unresolved head segment favor proper H tetramerization and counteract interactions between subunits from different tetramers. The structurally unresolved H-head segment, together with the top of the stalk, may act as a leash to provide the right degree of freedom for the heads of individual tetramers to adopt a triggering-permissive conformation while avoiding improper contacts with heads of neighboring tetramers.IMPORTANCEUnderstanding the molecular mechanism of membrane fusion triggering may allow development of new antiviral strategies. The fusion apparatus of paramyxoviruses consists of a receptor binding tetramer and a fusion protein trimer. Structural analyses of the receptor binding hemagglutinin-neuraminidases of certain paramyxoviruses suggest that fusion triggering is preceded by relocation of its head domains, facilitated by flexible linkers. Having noted a structurally unresolved 17-residue segment linking the globular heads to the tetrameric stalk of the measles virus hemagglutinin (H), we asked whether and how it may facilitate membrane fusion triggering. We conclude that, together with the top of the stalk, the flexible linker keeps H heads on a leash long enough to adopt a triggering-permissive conformation but short enough to limit roaming and improper contacts with heads of neighboring tetramers. All morbillivirus H-protein heads appear to be connected to their stalks through a “leash,” suggesting a conserved triggering mechanism.

Meaning and function of dummy auxiliaries in adult acquisition of Dutch as an additional language

This article presents the results of experimental data on language production and comprehension. These show that adult learners of Dutch as an additional language, with different language backgrounds, and a L2 proficiency below level A2 (Waystage) of the Common European Framework of Reference for Languages (CEFR; Council of Europe, 2001), use dummy auxiliaries as a structural device and interpret them as semantically vacuous. Proficiency level in the target language, more than language background, seems to determine the occurrence of dummy auxiliaries, and also which dummy auxiliary is used. Participants at a lower level of language acquisition use both dummy auxiliaries zijn (‘be’) and gaan (‘go’), whereas more advanced learners continue using predominantly dummy auxiliary gaan. These findings suggest that both dummy auxiliaries have a trigger function in setting the step from nonfinite utterances, to utterances with dummy auxiliaries carrying morphological information, and finally to utterances in which the morphological information is carried by the finite verb.