Identifying strategic management concepts: An analytic network process approach

This paper presents an approach to the identification of an organization’s strategic management concepts (SMCs) – mission, vision, values and competences. The highly qualitative relationships among these concepts are operationalized using the Analytic Network Process (ANP). As ANP captures the outcome of dependence and feedback between components of elements, the proposed approach enables us to handle indirect relationships and complex interactions existing among the SMCs. The alternatives with the highest overall priorities, resulting from the ANP, are selected as the organization’s most dominant SMC set. To improve the quality of the decision further analysis of the ANP results is suggested. Accordingly, alternative concept sets are derived by applying two approaches – bottom-up and top-down. The bottom-up approach indicates an explorative perspective where only common values and core competences held by the organization are used to identify the corresponding mission and vision statements. On the other hand, the top-down approach indicates a normative perspective where the necessary values and competences are determined according to a given desired vision statement. The proposed ANP approach has been applied to the Industrial Engineering Department (IED) of Istanbul Technical University. In light of the dominant, bottom-up and top-down sets, a final set of SMCs has been suggested for the IED.     

On the feasibility of re-stimulation of shale wells

As a result of advances in horizontal completions and multi-stage hydraulic fracturing, the U.S. has been able to economically develop several decades of worth of natural gas. However, a considerable concern has risen on the economic viability of shale gas development for reasons associated with the fast production declines as well as recent down-turns of natural gas prices besides rises in the costs of new technologies. Therefore, an economic analysis is required to investigate the profitability of the refracturing treatment of unconventional gas resources. Net present value of cash flows and internal rate of return are calculated for a range of gas prices considering 20 years of natural gas production from a typical unconventional shale gas reservoir. A systematic comparison is then accomplished for three scenarios: (1) re-fracturing versus no refracturing, (2) combination of re-fracturing and drilling new wells, and (3) time-dependent re-fracturing treatment. Further, this paper incorporates the cost of re-fracturing treatment, the cost of drilling a new horizontal well, the water treatment cost, as well as the current and future price of natural gas in the model. The findings of this work would help the future re-stimulation development plans of the emerging unconventional shale gas plays.     

A Library for Self-Adjusting Computation

We present a Standard ML library for writing programs that automatically adjust to changes to their data. The library combines modifiable references and memoization to achieve efficient updates. We describe an implementation of the library and apply it to the problem of maintaining the convex hull of a dynamically changing set of points. Our experiments show that the overhead of the library is small, and that self-adjusting programs can adjust to small changes three-orders of magnitude faster than recomputing from scratch. The implementation relies on invariants that could be enforced by a modal type system. We show, using an existing language, abstract interfaces for modifiable references and for memoization that ensure the same safety properties without the use of modal types. The interface for memoization, however, does not scale well, suggesting a language-based approach to be preferable after all.     

Causes of Collapse and Damage to Low-Rise RC Buildings in Recent Turkish Earthquakes

This study assesses performance objectives defined in the Turkish Earthquake Code (TEC) in order to make a realistic evaluation related to heavy damage and collapse reasons of reinforced concrete (RC) buildings that experienced severe earthquakes in Turkey. A series of three-dimensional RC buildings with different characteristics and representing low-rise structures damaged and collapsed in the earthquake areas is designed according to Turkish codes (Turkish Design Standards and Turkish Earthquake Code). Pushover analyses are carried out to determine nonlinear behavior of the buildings under earthquake loads. Building performances are determined by using the displacement coefficients method, which is a commonly used nonlinear static evaluation procedure for different seismic hazard levels defined in the TEC. The stipulated performance objectives in the TEC are checked in terms of plastic rotations and maximum story drift. From the results of this research, it can be concluded that low-rise RC buildings designed according to Turkish codes sufficiently provide for the performance objectives stipulated in the TEC. Reasons for the heavy damages and collapses of RC buildings during severe earthquakes are explained by commonly occurring themes (i.e., project errors, poor quality of construction, modifications of buildings, etc.).     

Large-scale evaluation of multimodal biometric authentication using state-of-the-art systems

We examine the performance of multimodal biometric authentication systems using state-of-the-art commercial off-the-shelf (COTS) fingerprint and face biometric systems on a population approaching 1,000 individuals. The majority of prior studies of multimodal biometrics have been limited to relatively low accuracy non-COTS systems and populations of a few hundred users. Our work is the first to demonstrate that multimodal fingerprint and face biometric systems can achieve significant accuracy gains over either biometric alone, even when using highly accurate COTS systems on a relatively large-scale population. In addition to examining well-known multimodal methods, we introduce new methods of normalization and fusion that further improve the accuracy.     

Open cell lead foams: processing, microstructure, and mechanical properties

Open cell lead foams with the porosities between 48 and 74 % were prepared by means of powder metallurgical and casting routes, using ammonium bicarbonate particles, silica beads, and sodium chloride salt particles as space holder. The resulting foam samples structure closely resembled open cell foam structure: each cell had few interconnections with neighboring cells. Small-sized lead (II) fluoride precipitates were microscopically observed in the interior of cells in the foam samples prepared using silica beads as space holder, resulting from the reaction between silica and hydrofluoric acid in the space holder dissolution step. The compression stress–strain curve of foam samples prepared by powder metallurgical route showed brittle deformation behavior following the initial elastic deformation region, while the foam samples prepared by casting route showed characteristic foam deformation behavior: cell edge crushing on the bent cell walls, and cell wall tearing. The collapse stresses, densification strains, and elastic moduli of the prepared foams were further fitted with scaling relations.     

Ultrasonic characterization of lactose crystallization in gelatin gels

Ultrasonic velocity and attenuation measurements (2.25 MHz center frequency) were used to follow bulk crystallization of lactose (43% and 46%) from gelatin (1.5% and 3%) gels at 25 °C, and compared to turbidity (500 nm) and isothermal calorimetric measurements. Ultrasonic velocity decreased slightly (approximately 0.5%) during crystallization while ultrasonic attenuation was low in the absence of lactose crystals and increased progressively during crystallization. The lag time before the onset of crystallization decreased and the maximum rate of increase in attenuation during crystallization increased with increasing lactose supersaturation but was not affected by gelatin concentration (P < 0.05). Similar results were seen in turbidity and isothermal calorimetric measurements. Ultrasonic attenuation measurements have the potential to measure crystallization kinetics in complex food matrices and to be applied on-line. Practical Application: Many foods contain crystals that affect their taste and texture (for example, lactose crystals can give a grainy defect in ice cream). The formation of crystals is often hard to predict so methods to measure the development of crystals inside real foods are useful. In this study, we show that as lactose crystallizes in a gelatin gel the ultrasonic attenuation--capacity to absorb sound--increases and can be related to the amount of crystals present. Ultrasound is easier to apply in real food processing than the existing methodologies.     

Identification of Turkish extra virgin olive oils produced in different regions by using NMR (1H and 13C) and IRMS (13C/12C)

Isotope ratio mass spectroscopy (IRMS) and nuclear magnetic resonance (NMR) spectroscopy techniques are two of the analytical methods that are used to characterize food products. The aim of this study is to classify extra virgin olive oil (EVOO) samples collected from different regions of Turkey based on ¹H and ¹³C NMR spectra along with IRMS δ¹³C carbon isotope ratio data by using chemometrics multivariate data analysis methods. A total of 175 EVOO samples were analyzed in 2014/15 and 2015/16 harvest seasons. Multivariate classification and clustering models were used to identify geographical and botanical origins of the EVOOs. IRMS results showed that there was no significant difference in terms of δ¹³C values between the years in terms of harvest year (p > 0.05), only extraction phase and variety were statistically significant factors (p < 0.05). The interactions of the factors showed that the harvest year × variety interaction is important. The outcomes of this research clearly indicated that considering the partial least squares discriminant analysis result with NMR spectra, the percent success of the model in the South Marmara, North Aegean, and South Aegean region samples were 95%, 95.7%, and 96.4% in the model set, respectively. The results showed that by using classification and clustering models, geographic marking and labeling of these oils can be carried out regardless of differences in year and production systems (2 and 3 phase extraction system) according the NMR analysis.     

Properties of electrodeposited Fe–Cu films grown on ITO coated glass substrates at different electrolyte temperatures

In this study, effect of electrolyte temperature on structural and morphological properties of Fe–Cu films electrodeposited on ITO coated glass substrates has been investigated. Structural analysis carried out by using X-ray diffraction indicated that the films consist of a mixture of face-centered cubic (FCC) Cu and body centered cubic (BCC) α-Fe phases. It was found that the crystalline size of both Fe and Cu increases with increasing electrolyte temperature. Compositional analysis performed using energy dispersive X-ray spectroscopy showed that the Cu content within the films enhances with increasing electrolyte temperature. The surface morphology of Fe–Cu films was studied using a scanning electron microscopy (SEM). SEM results indicated that the surface morphology of Fe–Cu films significantly depends on the electrolyte temperature. The investigation of the residual stress in the films indicated that the residual stress for the FCC Cu is tensile in all films regardless of electrolyte temperature, whereas, for the BCC Fe, it depends on the electrolyte temperature. Correlation between the surface morphology and the residual stress is discussed in terms of the obtained results.     

Relay Multi-hop Communications for Next Generation Mobile Networks: Investigation of Path-Loss Models

In next generation communication systems, a multi-hop scheme, in which stations between a mobile terminal and a base station relay signal transmissions, seems a promising ap-proach for wide-area coverage and system capacity enhancement. Another prospective benefit for multi-hop scheme is the reduction of transmission power for a link. This reduction is expected by splitting the transmission into a series of hops using the other mobile stations as repeaters which provide a gain from receiver (Rx) to transmitter (Tx). In this way, the transmission power is expected to become less due to the non-linear nature of the path loss. In this work, different path loss models are examined for multi-hop communication systems. Direct communication and the multi-hop communication cases are compared according to different path loss models. The question of how path loss changes by splitting the transmission into a series of sub-paths is also investigated. The investigations show that it is not possible to reduce the path losses except for some cases thus the transmit power. On the other hand using the multi-hop scheme makes possible to increase the coverage area of the network and also reduce the dead spots in the cell.