Investment Rate vs Relative price of Investment

In this paper I accomplish a levels account exercise across countries in order to calculate contributions from differences in the relative price of investment and the investment rate to differences in the physical capital-output ratio -and consequently in output per worker- across countries. I find that differences in the relative price of investment account for most differences in the physical capital-output ratio across countries and, consequently, if capital share on income is broadly consistent with national income accounts data, they have a moderate importance in accounting for differences in output per worker. However, differences in the investment rate account for very little disparity in physical capital-output ratio and output per worker across countriesPhysical capital-output ratio; Output per worker; Investment rate; Relative price of investment

Existence, Uniqueness and Stability of Equilibrium in an Overlapping Generation Model with Monopolistic Competition and Free Entry and Exit of Firms

In this paper we have analyzed existence, uniqueness and stability of a steady-state equilibrium in an overlapping generations model with monopolistic competition and free entry and exit of firms. We establish a strenghtened Inada condition that is sufficient to exclude global contraction for any given set of well-behaved preferences. We also establish sufficient conditions for a non-trivial steady-state equilibrium to exist, and also sufficient conditions for its uniqueness and global stability. We show that the size of mark-up over marginal cost and the particular mix of fixed costs play a crucial role in these conditions and consequently on the dynamic behavior of the economyEquilibrium; Existence; Monopolistic Competition; Overlapping Generations; Stability; Uniqueness

SISTEM KENDALI DAN MONITOR DAYA LISTRIK PADA PERANGKAT LISTRIK RUMAH BERBASIS IOT

Internet of Things adalah salah satu prinsip teknologi yang digunakan untuk mengendalikan perangkat melalui jaringan internet. Internet of Things telah banyak digunakan dalam kehidupan sehari-hari untuk memudahkan pengguna dalam mengendalikan perangkat dengan jarak yang jauh. Salah satu contoh pengembangan Internet of Things ini adalah pengontrolan perangkat listrik melalui aplikasi smartphone dalam rumah. Aplikasi smartphone ini akan menampilkan penggunaan daya listrik pada peralatan listrik rumah yang digunakan dalam kehidupan sehari-hari. Pengendalian aplikasi ini dilakukan dengan pengiriman data antara perangkat yang dikendalikan dan aplikasi smartphone melalui jaringan internet. Aplikasi tersebut akan menampilkan penggunaan tegangan, arus, daya, serta faktor daya yang digunakan oleh perangkat. Proses ini didukung oleh komponen nodeMCU berfungsi sebagai pengendali untuk menghidupkan atau mematikan peralatan listrik serta melakukan pengiriman data daya yang diperoleh dari sensor arus ACS712 dan sensor tegangan ZMPT101B menuju database server. Data yang tersimpan tersebut ditampilkan melalui smartphone pengguna Dari 30 kali pengujian untuk membandingkan hasil baca daya dari sensor dengan alat ukur yang sudah ada. Sistem ini memiliki tingkat error yang rendah yaitu sebesar 3,13% pada saklar 1 dan 3,41% pada saklar 2. Pengukuran ini juga memiliki tingkat presisi yang cukup tinggi untuk sensor tegangan sebesar 1,97% dan 1,41% serta untuk sensor arus sebesar 0,03

Technological Progress, Obsolescence and Depreciation

We construct a vintage capital model à la Whelan (2002) with both exogenous embodied and disembodied technical progress, and variable utilization of each vintage. The lifetime of capital goods is endogenous and it relies on the associated maintenance costs. We study the properties of the balanced growth paths. First, we show that the lifetime of capital is an increasing (resp. decreasing) function of the rate of disembodied (resp.embodied) technical progress. Second, we show that both the use-related depreciation rate and the scrapping rate incease when embodied technical progress accelerates. However, the latter drops when disembodied technical progress accelerates while the former remains unaffected. A key feature of our model is that the age-related depreciation rate does depend on the obsolescence rate in sharp contrast to the neoclassical model.Vintage capital; operation costs; embodied technical progress; age-related depreciation; obsolescence

Embodied technological change learning-by-doing and the productivity slowdown

The productivity slowdown faced by the US economy since the first oil shock has been associated with a rise in the decline rate of the relative price of equipment and a reduction in the rate of disembodied technical change. We build up a growth model in which learning-by-doing is the engine of both embodied and disembodied technological progress. A change in the relative efficiency of learning-by-doing from the consumption to the investment sector is shown to imply a technological reassignment consistent with the above mentioned evidence. This result derives from the interaction between the obsolescence costs inherent to embodiment and the learning-by-doing engine.Embodied technical progress, Obsolescence, Learning-by-doing, Productivity slowdown

Obsolescence and Modernization in the Growth Process

In this paper, an endogenous growth model is built up incorporating Schumpeterian growth and embodied technological progress. Under embodiment, long run growth is affected by the following effects : (i) obsolescence costs add to the user cost of capital, reducing the research effort; and (ii) the modernization of capital through investment raises the incentives to undertake R&D activities. Applied to the understanding of the growth enhancing role of both capital and R&D subsidies, we conclude that the positive effect of modernization generally more than compensate the negative effect of obsolescenceShumpeterian growth; Creative destruction; Embodiment;Obsolescence; Modernization

Vintage capital and the dynamics of the AK model

This paper analyzes the equilibrium dynamics of an AK-type endogenous growth model with vintage capital. The inclusion of vintage capital leads to oscillatory dynamics governed by replacement echoes, which additionally influence the intercept of the balanced growth path. These features, which are in sharp contrast to those from the standard AK model, can contribute to explaining the short-run deviations observed between investment and growth rates time series. To characterize the optimal solutions of the model we develop analytical and numerical methods that should be of interest for the general resolution of endogenous growth models with vintage capital.Endogenous growth, Vintage capital, AK model, Differencedifferential equations

Obsolescence and productivity

The increase in the obsolescence of intangible capital caused by the adop- tion of new information technologies can play an important role in accounting for the productivity slowdown undergone by the US economy since 1974. To explore this hypothesis, we have developed a standard growth model with physical and intangi- ble capital in which technical progress is equipment–specific. We assume that the obsolescence of intangible capital increases when the equipment–specific techni- cal progress accelerates. The model is calibrated for the period 1957–1973 and the response of the economy to an increase in the rate of equipment–specific technical progress — as observed since 1974 — is simulated. We show that this setup can account for a large part of the post–1974 slowdown observed in productivity and in the Solow residual.info:eu-repo/semantics/publishedVersio

Evolution, survival and anomalies

Rio, A., & Abreu, F. B. E. (2023). PHP code smells in web apps: Evolution, survival and anomalies. Journal of Systems and Software, 200, 1-23. [111644]. https://doi.org/10.1016/j.jss.2023.111644Abstract Context: Code smells are symptoms of poor design, leading to future problems, such as reduced maintainability. Therefore, it becomes necessary to understand their evolution and how long they stay in code. This paper presents a longitudinal study on the evolution and survival of code smells (CS) for web apps built with PHP, the most widely used server-side programming language in web development and seldom studied. Objectives: We aimed to discover how CS evolve and what is their survival/lifespan in typical PHP web apps. Does CS survival depend on their scope or app life period? Are there sudden variations (anomalies) in the density of CS through the evolution of web apps? Method: We analyzed the evolution of 18 CS in 12 PHP web applications and compared it with changes in app and team size. We characterized the distribution of CS and used survival analysis techniques to study CS’ lifespan. We specialized the survival studies into localized (specific location) and scattered CS (spanning multiple classes/methods) categories. We further split the observations for each web app into two consecutive time frames. As for the CS evolution anomalies, we standardized their detection criteria. Results: The CS density trend along the evolution of PHP web apps is mostly stable, with variations, and correlates with the developer’s numbers. We identified the smells that survived the most. CS live an average of about 37% of the life of the applications, almost 4 years on average in our study; around 61% of CS introduced are removed. Most applications have different survival times for localized and scattered CS, and localized CS have a shorter life. The CS survival time is shorter and more CS are introduced and removed in the first half of the life of the applications. We found anomalies in the evolution of 5 apps and show how a graphical representation of sudden variations found in the evolution of CS unveils the story of a development project. Conclusion: CS stay a long time in code. The removal rate is low and did not change substantially in recent years. An effort should be made to avoid this bad behavior and change the CS density trend to decrease.publishersversionepub_ahead_of_prin