Benchmarking and viability assessment of optical packet switching for metro networks

Optical packet switching (OPS) has been proposed as a strong candidate for future metro networks. This paper assesses the viability of an OPS-based ring architecture as proposed within the research project DAVID (Data And Voice Integration on DWDM), funded by the European Commission through the Information Society Technologies (IST) framework. Its feasibility is discussed from a physical-layer point of view, and its limitations in size are explored. Through dimensioning studies, we show that the proposed OPS architecture is competitive with respect to alternative metropolitan area network (MAN) approaches, including synchronous digital hierarchy, resilient packet rings (RPR), and star-based Ethernet. Finally, the proposed OPS architectures are discussed from a logical performance point of view, and a high-quality scheduling algorithm to control the packet-switching operations in the rings is explained

Assessment of First Comer Advantages and Network Effects; the Case of Turkish GSM Market

First comer advantages and network effects are frequently stated as among the most important determinants of market structures and this is particularly relevant for network economies including telecommunications markets. Connected to this, regulatory tools such as number portability have frequently been used to reduce market imperfections resulting from these effects. Within this context, this paper aims to analyze the role of these factors in creating the current market structure of Turkish GSM sector. By examining relevant data such as development of market shares in a historical perspective and by making use of consumer surveys, it is concluded that the dominant operator has benefited from being first comer in the market and established a stable market share (power) due to network effects that are used by this firm deliberately to entrench its position especially in the form of switching costs, scale economies, brand image and tariff (on-net vs. off-net pricing) differentiation; however, it is also observed that introduction of number portability lead to reduction in switching costs, increasing market competition. --First comer advantages,Network effects,Mobile telephony (GSM),number portability,Competition,Regulation and Consumer preferences

Co-ordination and Lock-in: Competition with Switching Costs and Network Effects

Switching costs and network effects bind customers to vendors if products are incompatible, locking customers or even markets in to early choices. Lock-in hinders customers from changing suppliers in response to (predictable or unpredictable) changes in effciency, and gives vendors lucrative ex post market power-over the same buyer in the case of switching costs (or brand loyalty), or over others with network effects. Firms compete ex ante for this ex post power, using penetration pricing, introductory offers, and price wars. Such "competition for the market" or "life-cycle competition" can adequately replace ordinary compatible competition, and can even be fiercer than compatible competition by weakening differentiation. More often, however, incompatible competition not only involves direct effciency losses but also softens competition and magnifies incumbency advantages. With network effects, established firms have little incentive to offer better deals when buyers’ and complementors’ expectations hinge on non-effciency factors (especially history such as past market shares), and although competition between incompatible networks is initially unstable and sensitive to competitive offers and random events, it later "tips" to monopoly, after which entry is hard, often even too hard given incompatibility. And while switching costs can encourage small-scale entry, they discourage sellers from raiding one another’s existing customers, and s also discourage more aggressive entry. Because of these competitive effects, even ineffcient incompatible competition is often more profitable than compatible competition, especially for dominant rms with installed-base or expectational advantages. Thus firms probably seek incompatibility too often. We therefore favor thoughtfully pro-compatibility public policy.

The 2020 Vertical Merger Guidelines: A Suggested Revision (March 26, 2020)

The FTC and DOJ requested comments on their draft Vertical Merger Guidelines in January 2020. This article is a complete alternative set of suggested Vertical Merger Guidelines that reflects and supplements the approach explained in the comments submitted by the author along with Jonathan. Baker, Nancy Rose and Fiona Scott Morton, as well as their other comments, and might be read in conjunction with those comments. This suggested revision of the Agencies’ draft expands the list of potential competition harms and provides illustrative examples. It expands and unifies the discussion and treatment of potential competitive benefits. It deletes the quasi-safe harbor and suggests the circumstances under which competitive harms raise lessened concerns on the one hand and heightened concerns on the other

Expectations, Network Effects and Timing of Technology Adoption: Some Empirical Evidence from a Sample of SMEs in Italy

We provide evidence on the influence of expectations and network effects on the timing of technological adoption. By considering a sample of SMEs operating in Italy we focus on the determinants of their decision to adopt Fast Ethernet, a communication standard for Local Area Networks (LANs). We find that both expectations and network effects significantly affect the timing of adoption. In particular, price expectations generally tend to delay adoption and (indirect) network effects in the form of backward compatibility as well as informational spillovers tend to foster adoption. Firm size also matters.diffusion, network effects, expectations, LAN equipment, SMEs

Hierarchical control over effortful behavior by rodent medial frontal cortex : a computational model

The anterior cingulate cortex (ACC) has been the focus of intense research interest in recent years. Although separate theories relate ACC function variously to conflict monitoring, reward processing, action selection, decision making, and more, damage to the ACC mostly spares performance on tasks that exercise these functions, indicating that they are not in fact unique to the ACC. Further, most theories do not address the most salient consequence of ACC damage: impoverished action generation in the presence of normal motor ability. In this study we develop a computational model of the rodent medial prefrontal cortex that accounts for the behavioral sequelae of ACC damage, unifies many of the cognitive functions attributed to it, and provides a solution to an outstanding question in cognitive control research-how the control system determines and motivates what tasks to perform. The theory derives from recent developments in the formal study of hierarchical control and learning that highlight computational efficiencies afforded when collections of actions are represented based on their conjoint goals. According to this position, the ACC utilizes reward information to select tasks that are then accomplished through top-down control over action selection by the striatum. Computational simulations capture animal lesion data that implicate the medial prefrontal cortex in regulating physical and cognitive effort. Overall, this theory provides a unifying theoretical framework for understanding the ACC in terms of the pivotal role it plays in the hierarchical organization of effortful behavior

Can monolinguals be like bilinguals? Evidence from dialect switching

Bilinguals rely on cognitive control mechanisms like selective activation and inhibition of lexical entries to prevent intrusions from the non-target language. We present cross-linguistic evidence that these mechanisms also operate in bidialectals. Thirty-two native German speakers who sometimes use the Öcher Platt dialect, and thirty-two native English speakers who sometimes use the Dundonian Scots dialect completed a dialect-switching task. Naming latencies were higher for switch than for non-switch trials, and lower for cognate compared to non-cognate nouns. Switch costs were symmetrical, regardless of whether participants actively used the dialect or not. In contrast, sixteen monodialectal English speakers, who performed the dialectswitching task after being trained on the Dundonian words, showed asymmetrical switch costs with longer latencies when switching back into Standard English. These results are reminiscent of findings for balanced vs. unbalanced bilinguals, and suggest that monolingual dialect speakers can recruit control mechanisms in similar ways as bilinguals