Three essays on operations management : commodity market, sustainability, and globalization

textThis dissertation deals with three issues that are important to many firms, namely, volatile commodity prices, environmental regulations, and globalization. In the first essay I study the benefit and the coordination of inventory sharing when there are two existing channels for procurement, i.e., the spot and forward markets. I propose a method for sharing inventory such that the decentralized firms get the same benefit per unit of the sharing transactions regardless of whether the firm is borrowing or lending. The procurement cost gap between the centralized and decentralized cases is dramatically small by using this method. In the second essay, I analyze whether imposing carbon costs to retailers and consumers changes the supply chain design or social welfare. I consider three types of players who want to maximize different objectives and three kinds of competitive settings. Different from previous studies, I show that the supply chain design is changed significantly by imposing carbon costs especially when market competition is medium to high. In the third essay, I consider long-term / short-term strategies of multi-national corporations. For the long-term strategy, I show that the correlation between the exchange rate and the market demand in a foreign country affects plant location. For the short-term strategy, I show that manufacturers increase the inventory levels as the exchange rate of the country where the plant is located grows weaker. I confirm these results empirically using plant-level data of Korean multi-national corporations provided by the Export-Import Bank of Korea.Information, Risk, and Operations Management (IROM

Investigaciones sobre los muros de Moen-Jo-Daro usando propiedades mecánicas

[EN] This investigation is based on the event that occur in 2000 and 2012 at Moen-Jo-Daro the extensive decay of Moen-Jo-Daro wall that replacement of bricks with new over damaged bricks. Damaged bricks due to the formation of various generated forces, continutiy of thrust resulted in the progressive instability of the lateral wall and formation of minor and major cracks. There are several walls which are facing similar problem, hence, a cubical clay model in 1/4-scale was built and investegated under service conditions. Finite-element FE, Models were generated to simulate the response of the structure, behaviour and safety of the prototype.[ES] Esta investigación se basa en los eventos que afectaron a Moen-Jo-Daro entre los años 2000 y 2012, pues por el deterioro en la pared de Moen-Jo-Daro tuvieron que reemplazarse ladrillos dañados por nuevos. Varios fueron los factores que produjeron el deterioro de los ladrillos que, junto al continuo empuje producido por el comportamiento estructural, dieron como resultado una progresiva inestabilidad en la pared lateral asi como la formación de grietas de menor y mayor envergadura. Hay varias paredes que se enfrentan a problemas similares, por lo tanto, un modelo cúbico de arcilla a escala 1/4 fue construido e investigado en condiciones de servicio. Usando elementos finitos FE, se generaron modelos para simular la respuesta de la estructura, el comportamiento y la seguridad del prototipo.Umair Khan, SM.; Park, JS. (2014). An Investigation of Shear Wall of Moen-Jo-Daro Using Mechanical Properties. Virtual Archaeology Review. 5(10):127-139. https://doi.org/10.4995/var.2014.4226OJS127139510GOUDIE, A.S. (1977): "Sodium sulphate weathering and the disintegration of Moenjodaro, Pakistan", Earth Surface Processes, Vol. 2, pp. 75-85. Pakistan. http://dx.doi.org/10.1002/esp.3290020108HUGHES, R. (1995): "Moenjodaro mission report", unpublished document, UNESCO, Paris. Shaikh, K.H. and Ashfaque, S.M. (1981), Moenjodaro: A 5000-year-old Legacy, UNESCO, Paris.QADIR BHATTI, A. (2012): Diagnosis, Monitoring and Repair Analysis of Historical Construction Material and Conservation Techniques in MohenjoDaro Islamabad, Pakistan.MEMON SINDHI M.A (2001): ڙڪاٹو لا Mohen Jo Daro publishing agency, Pakistan.MORTIMER, W. (1953): The Indus Civilization The Cambridge History of India, India.MORYANI, J. موهنجودڙو (2011): Sindh adbi academy Karachi, Pakistan.PANWAR, M.H. (2011): Six Thousand years of History of Irrigaction in Sindh. Pakistan.SULTAN ARYANE, A. (1972): Moenjo Daro, Preservation Plan (ground water control) Pakistan.TEUTONICO, J.M. (Ed.) (1985): International Architectural Conservation Course Laboratory Manual, ICCROM, Rome

Low-voltage-driven soft actuators

Soft actuators based on electroactive polymers (EAPs) are the core constituents of future soft robots owing to their fascinating properties such as Lightweight, compactness, easy fabrication into various forms, and Low cost. Ionic EAP actuators are particularly attractive owing to the Low driving voltages (<3 V) as compared to those of electronic EAP actuators (usually kilovolts). This paper presents a brief overview of the recent progress in a range of EAP actuators by focusing on Low voltage operation, in addition to the challenges and future strategies for their wide applicability in artificial muscles and various innovative soft robot technologies.11Ysciescopu

The Light and Period Variations of the Eclipsing Binary BX Draconis

New CCD photometric observations of BX Dra were obtained for 26 nights from 2009 April to 2010 June. The long-term photometric behaviors of the system are presented from detailed studies of the period and light variations, based on the historical data and our new observations. All available light curves display total eclipses at secondary minima and inverse O'Connell effects with Max I fainter than Max II, which are satisfactorily modeled by adding the slightly time-varying hot spot on the primary star. A total of 87 times of minimum light spanning over about 74 yrs, including our 22 timing measurements, were used for ephemeris computations. Detailed analysis of the O-C diagram showed that the orbital period has changed in combinations with an upward parabola and a sinusoidal variation. The continuous period increase with a rate of +5.65 \times 10^-7 d yr^-1 is consistent with that calculated from the Wilson-Devinney synthesis code. It can be interpreted as a mass transfer from the secondary to the primary star at a rate of 2.74 \times 10^-7 M\odot yr^-1, which is one of the largest rates for contact systems. The most likely explanation of the sinusoidal variation with a period of 30.2 yrs and a semi-amplitude of 0.0062 d is a light-traveltime effect due to the existence of a circumbinary object. We suggest that BX Dra is probably a triple system, consisting of a primary star with a spectral type of F0, its secondary component of spectral type F1-2, and an unseen circumbinary object with a minimum mass of M3 = 0.23 M\odot.Comment: 24 pages, including 5 figures and 9 tables, accepted for publication in PAS

Competing states for the fractional quantum Hall effect in the 1/3-filled second Landau level

In this work, we investigate the nature of the fractional quantum Hall state in the 1/3-filled second Landau level (SLL) at filling factor $\nu=7/3$ (and 8/3 in the presence of the particle-hole symmetry) via exact diagonalization in both torus and spherical geometries. Specifically, we compute the overlap between the exact 7/3 ground state and various competing states including (i) the Laughlin state, (ii) the fermionic Haffnian state, (iii) the antisymmetrized product state of two composite fermion seas at 1/6 filling, and (iv) the particle-hole (PH) conjugate of the $Z_4$ parafermion state. All these trial states are constructed according to a guiding principle called the bilayer mapping approach, where a trial state is obtained as the antisymmetrized projection of a bilayer quantum Hall state with interlayer distance $d$ as a variational parameter. Under the proper understanding of the ground-state degeneracy in the torus geometry, the $Z_4$ parafermion state can be obtained as the antisymmetrized projection of the Halperin (330) state. Similarly, it is proved in this work that the fermionic Haffnian state can be obtained as the antisymmetrized projection of the Halperin (551) state. It is shown that, while extremely accurate at sufficiently large positive Haldane pseudopotential variation $\delta V_1^{(1)}$, the Laughlin state loses its overlap with the exact 7/3 ground state significantly at $\delta V_1^{(1)} \simeq 0$. At slightly negative $\delta V_1^{(1)}$, it is shown that the PH-conjugated $Z_4$ parafermion state has a substantial overlap with the exact 7/3 ground state, which is the highest among the above four trial states.Comment: 22 pages, 5 figure