MODEL STOKASTIK SUSCEPTIBLE INFECTED RECOVERED (SIR)

Felin Yunita. 2013. MODEL STOKASTIK SUSCEPTIBLE INFECTED RECOVERED (SIR). Fakultas Matematika dan Ilmu Pengetahuan Alam. Universitas Sebelas Maret. Model susceptible infected recovered (SIR) menjelaskan penyebaran penyakit dari individu susceptible menjadi infected, kemudian individu infected akan sembuh (recovered) dan tidak terinfeksi kembali karena memiliki kekebalan. Penyebaran penyakit dapat dipandang sebagai kejadian random yang bergantung pada variabel waktu sehingga disebut proses stokastik. Perubahan banyaknya individu susceptible, infected, dan recovered merupakan proses stokastik dalam selang waktu dan variabel random kontinu sehingga dapat dijelaskan dengan model stokastik SIR. Tujuan penulisan ini adalah menurunkan model stokastik SIR. Penyelesaian model stokastik SIR diperoleh dengan formula Ito dan fungsi probabilitas variabel random dari model stokastik SIR harus memenuhi persamaan diferensial Kolmogorov maju. Model stokastik SIR disimulasikan dengan mengambil laju kontak �, laju kesembuhan , dan individu awal yang terinfeksi I(0) yang berbeda. Hasil simulasi menunjukkan bahwa jika semakin besar nilai � maka puncak epidemi semakin tinggi dan semakin besar nilai I(0) maka puncak epidemi juga semakin tinggi. Akan tetapi jika semakin besar nilai maka puncak epidemi semakin rendah. Kata kunci : formula Ito, model SIR, model stokastik, persamaan diferensial Kolmogorov Felin Yunita, 2013. SUSCEPTIBLE INFECTED RECOVERED (SIR) STOCHASTIC MODEL. Faculty of Mathematics and Natural Sciences, Sebelas Maret University. The susceptible infected recovered (SIR) model explains the spread of a disease from the susceptible individuals become infected individuals, then the infected individuals will be recovered and will be not re-infected because they have immunity. The spread of disease is considered as random events which depend on the time variable so it is called a stochastic process. The changes of the number of susceptible, infected, and recovered individuals are a stochastic process with continuous time interval and random variable that can be explained by a SIR stochastic model The purpose of this research is to construct the SIR stochastic model. The solution of the SIR stochastic model is obtained by the Ito formula and the probability function of random variables from the SIR stochastic model must satisfy the Kolmogorov forward differential equations. The SIR stochastic model is simulated by taking the various values of the contact rate �, the recovery rate , and the initial value of infected I(0). The results of simulation show the more value of �, the higher of outbreak, and the more value of I(0), the higher of outbreak. On the other hand the more value of , the lower of outbreak. Key words : Ito formula, Kolmogorov differential equations, SIR model, stochastic mode

Building Micro-Foundations for the Routines, Capabilities, and Performance Links

Micro-foundations have become an important emerging theme in strategic management. This paper addresses micro-foundations in two related ways. First, we argue that the kind of macro (or “collectivist”) explanation that is utilized in the capabilities view in strategic management ? which implies a neglect of micro-foundations ? is incomplete. There are no mechanisms that work solely on the macro-level, directly connecting routines and capabilities to firm-level outcomes. While routines and capabilities are useful shorthand for complicated patterns of individual action and interaction, ultimately they are best understood at the micro-level. Second, we provide a formal model that shows precisely why macro explanation is incomplete and which exemplifies how explicit micro-foundations may be built for notions of routines and capabilities and for how these impact firm performance.Routines, capabilities, micro-foundations, production function

Nudge: Manager as Choice Architect

In this paper I discuss the role of manager as choice architect. The notion of nudging and choice architecture has received significant interest in law, economics and public policy. But the behavioral insights from this literature also have important implications for managers, HR professionals and organizations. In essence, employees are consumers of choice and are constantly confronted with a large array and interface of options, and this interface can be designed so as to maximize individual welfare and organizational outcomes. I first discuss the theoretical foundations of the nudge idea and then highlight how managers can design effective choice architectures for the management of human capital. By way of illustration, I specifically focus on four practical areas: 1) nudge hiring, 2) nudge training and development, 3) nudge human capital and organization, and 4) nudge strategy and innovation. Throughout the paper I also point out comparative differences in decision making between contexts (e.g., consumer choice versus decision making in organizations), including implied debates, and also highlight novel opportunities for future research in management and strategy. I particularly focus on the possibilities associated with nudges and choice architectures at the nexus of organizations, crowds and aggregate decision making

Pengaruh Growth Opportunity, Leverage dan Firm Size terhadap Cash Holding Perusahaan Properti dan Real Estate

Adapun tujuan dari penelitian ini adalah untuk mengetahui dan menguji hubungan Growth Opportunity, Leverage dan Firm Size terhadap Cash Holding pada perusahaan Properti dan Real Estate yang terdaftar di Bursa Efek Indonesia periode 2014-2017. Penelitian ini adalah penelitian kuantitatif dan pendekatan deduktif bersifat deskriptif. Jumlah populasi adalah 49 perusahaan properti & real estate yang ada di BEI periode 2014-2017. Teknik sampel menggunakan sampling purposive sehingga sampel penelitian yang memenuhi kriteria sebanyak 31 perusahaan. Metode pengumpulan data menggunakan data sekunder yang berasal dari laporan keuangan sedangkan model analisis data adalah regresi berganda. Hasil penelitian uji F yaitu Growth Opportunity, Leverage dan Firm Size berpengaruh terhadap Cash Holding. Secara individu Growth Opportunity tidak memiliki pengaruh terhadap Cash Holding sedangkan Leverage dan Firm Size memiliki pengaruh positif dan signifikan terhadap Cash Holding. Nilai koefisien determinasi yang dilihat dari Adjusted R2 sebesar 0,256 yang menunjukkan bahwa cash holding dapat dipengaruhi oleh Growth Opportunity, Leverage dan Firm Size sebesar 25,6%, dan sebesar 74,4% merupakan faktor lain yang tidak diajukan dalam laporan penelitian ini

Untangling Infinite Regress and the Origins of Capability

We argue that strategic management in general—and capability theory in particular—suffers from problems of infinite regress that can be traced to an unsatisfactory specification of initial conditions. We argue, first, that this has led to an overemphasis on path-dependence, experience and history, without sufficient attention on initial conditions: more proximate, decision-oriented punctuation points that can be used for better theoretical explanation. Second, we show how the initial conditions of theories are often not distinctively different from what is being explained, which prevents theory from providing credible specifications of causal mechanisms. Third, we highlight how the regress problem has led to a relatively casual borrowing of concepts from neighboring disciplines, which has created a mismatch between the aims of management theory and relevance to practice. We suggest research heuristics for how to deal with infinite regress problems, to develop more rigorous and relevant theories of capability and strategic management

MODEL STOKASTIK SUSCEPTIBLE INFECTED RECOVERED (SIR)

Model susceptible infected recovered (SIR) menjelaskan penyebaran penyakit dari individu susceptible menjadi infected, kemudian individu infected akan sembuh (recovered) dan tidak terinfeksi kembali karena memiliki kekebalan. Penyebaran penyakit dapat dipandang sebagai kejadian random yang bergantung pada variabel waktu sehingga disebut proses stokastik. Perubahan banyaknya individu susceptible, infected, dan recovered merupakan proses stokastik dalam selang waktu dan variabel random kontinu sehingga dapat dijelaskan dengan model stokastik SIR. Tujuan penulisan ini adalah menurunkan model stokastik SIR. Model stokastik SIR disimulasikan dengan mengambil laju kontak β, laju kesembuhan γ, dan individu awal yang terinfeksi I(0) yang berbeda. Hasil simulasi menunjukkan bahwa jika semakin besar nilai β maka puncak epidemi semakin tinggi dan semakin besar nilai I(0) maka puncak epidemi juga semakin tinggi. Akan tetapi jika semakin besar nilai γ maka puncak epidemi semakin rendah. Kata kunci: model SIR, model stokastik

Designing Organizations for Dynamic Capabilities

How can organizations put dynamic capabilities into practice? We focus on the power of organizational design, showing how managers can harness new organizational forms to build a capacity for sensing, shaping and seizing opportunities. Fast-moving environments favor open organization and self-organizing processes that quickly convert individual capabilities into actionable collective intellect. We argue that self-organizing processes do not organize themselves but require managers to design and execute them. We examine new design principles – such as polyarchy, social proofs, and new forms of open organization – that allow organizations to build dynamic capabilities for sustained innovation in dynamic environments