Modelling supplier selection and material purchasing for the construction supply chain in a fuzzy scenario-based environment

Mathematical relations between supplier capacities, the resulting material supply shortages, together with the impact of material delays on construction projects are not well defined. In response to this, this paper presents a novel multi-objective mixed integer linear programming model that considers the selection of suitable suppliers, inventory management practices, order quantities and the possibility of splitting a material order as integrated decisions to be optimised. The trade-off between the overall procurement cost and the weighted lateness, a measure of material delay impacts, is optimised. Material prices, supplier capacities, and resulting delays are treated as fuzzy scenario-based parameters. The proposed model is tested on a numerical example and computation experiments validate the model performance. An extensive sensitivity analysis is carried out and results suggest that by considering high variations in uncertain supplier capacities, the model would generate lower procurement cost and show less significant delay impacts. Whereas greater variations in uncertain material prices cause the total procurement cost to grow 55%; greater variations in uncertain delay durations also drastically increase the weighted lateness by over 70%. This highlights the importance of having high quality estimates for uncertain parameters. Additionally, the analysis also indicates that a minimum overall satisfaction level of 0.9338 can be achieved depending on the model user's strategies, and the proposed scenario-adjusted problem outperforms problems modelled under deterministic market conditions. The major contribution of this paper lies in the development of a fuzzy scenario-based model to solve the supplier selection and material purchasing problem in construction supply chains

Dasar – Dasar Program Perencanaan Dan Perancangan Arsitektur (DP3A) Redesain Terminal Kartasura

Tujuan dasar-dasar program perancangan dan Perancangan Arsitektur (DP3A) ini adalah untuk meningkatkan kualitas dan kuantitas pelayanan kepada masyarakat, untuk mendapatkan kemudahan dalam hal transportasi, khususnya angkutan bus, memberikan wadah untuk menarik para pengunjung dengan penambahan tata lansekap, dan merencanakan sirkulasi yang aman dan nyaman serta lancar sehingga tidak terjadi crossing antara kendaraan yang akan masuk dengan yang akan keluar serta di dalam terminal itu sendiri. Kondisi Terminal Kartasura saat ini bisa dikatakan jauh dari ideal sebagai terminal Tipe B. Hal ini dapat dilihat dari kurang maksimalnya pelayanan yang diberikan karena terjadi pergeseran-pergeseran fungsi. Permasalahan di dalam terminal Kartasura antara lain : 1) Bercampurnya arus sirkulasi orang (penumpang) dengan arus sirkulasi kendaraan, 2) Belum terdapat tempat penurunan penumpang, 3) Tempat penurunan dan jalur pemberangkatan menjadi satu tempat sehingga sirkulasi manusia bercampur aduk, 4) Fisik dan struktur bangunan yang mulai mengalami kerusakan dan tidak terurus untuk perawatannya, 5) Ruang terbuka terminal yang tidak terdapat pepohonan atau rumput yang dapat mengurangi polusi udara dan menyerap air. Untuk menganalisa perkembangan angkutan dan penduduk, maka di Kartasura dibutuhkan redesain terminal bus yang lebih representatif, sesuai dengan kaidah-kaidah arsitektural dengan mempertimbangkan struktur bangunan terminal, lansekap pada terminal dengan konsep bangunan melalui green architecture. Dalam mengantisipasi sirkulasi di dalam terminal Kartasura maka akan di ambil redesain terminal Kartasura dengan sistem parkir gergaji untuk jangka waktu pengoperasionalan selama ± 20 tahun ke depan. Terminal Kartasura maka perlu sebuah pola sirkulasi, sehingga dapat dapat disimpulkan bahwa pola sirkulasi pada terminal Kartasura yang akan diterapkan pada redesain dengan menggunakan sistem pembagian jalur arah yang berjalan atau searah agar dapat menghindari crossing antara arus armada dengan manusia, sedangkan dalam struktur bangunan, terminal Kartasura saat ini perlu terjadinya perbaikan, seperti pelataran yang kurang efisien, struktur bangunan yang perlu di perbaiki, sehingga perlu teori khusus struktur untuk merencanakan dalam meredesain terminal Kartasura dengan menggunakan struktur rangka ruang, karena bus dan pengunjung Terminal Kartasura nantinya membutuhkan akses yang luas, aman dan nyaman

Chronic koro-like symptoms – two case reports

BACKGROUND: Koro is a culture bound syndrome, which has been reported usually from Asian countries. It has been described as an acute, brief lasting illness, which often occurs in epidemics. There is no description in literature of a chronic form of this syndrome. CASE PRESENTATION: Two sporadic cases with koro-like symptoms from East India are presented where the illness had a chronic course with durations spanning more than ten years. In contrast to acute, good prognosis, psycho-education responsive form that is usually seen in epidemics; the chronic form, appeared to be associated with greater morbidity and poorer response to interventions. CONCLUSION: There is a possibility of a chronic form of koro syndrome

Delivering mesenchymal stem cells in collagen microsphere carriers to rabbit degenerative disc - Reduced risk of osteophyte formation.

Mesenchymal stem cells (MSCs) have the potential to treat early intervertebral disc (IVD) degeneration. However, during intradiscal injection, the vast majority of cells leaked out even in the presence of hydrogel carrier. Recent evidence suggests that annulus puncture is associated with cell leakage and contributes to osteophyte formation, an undesirable side effect. This suggests the significance of developing appropriate carriers for intradiscal delivery of MSCs. We previously developed a collagen microencapsulation platform, which entraps MSCs in a solid microsphere consisting of collagen nanofiber meshwork. These solid yet porous microspheres support MSC attachment, survival, proliferation, migration, differentiation, and matrix remodeling. Here we hypothesize that intradiscal injection of MSCs in collagen microspheres will outperform that of MSCs in saline in terms of better functional outcomes and reduced side effects. Specifically, we induced disc degeneration in rabbits and then intradiscally injected autologous MSCs, either packaged within collagen microspheres or directly suspended in saline, into different disc levels. Functional outcomes including hydration index and disc height were monitored regularly until 6 months. Upon sacrifice, the involved discs were harvested for histological, biochemical, and biomechanical evaluations. MSCs in collagen microspheres showed advantage over MSCs in saline in better maintaining the dynamic mechanical behavior but similar performance in hydration and disc height maintenance and matrix composition. More importantly, upon examination of gross appearance, radiograph, and histology of IVD, delivering MSCs in collagen microspheres significantly reduced the risk of osteophyte formation as compared to that in saline. This work demonstrates the significance of using cell carriers during intradiscal injection of MSCs in treating disc degeneration.published_or_final_versio

Semantic distillation: a method for clustering objects by their contextual specificity

Techniques for data-mining, latent semantic analysis, contextual search of databases, etc. have long ago been developed by computer scientists working on information retrieval (IR). Experimental scientists, from all disciplines, having to analyse large collections of raw experimental data (astronomical, physical, biological, etc.) have developed powerful methods for their statistical analysis and for clustering, categorising, and classifying objects. Finally, physicists have developed a theory of quantum measurement, unifying the logical, algebraic, and probabilistic aspects of queries into a single formalism. The purpose of this paper is twofold: first to show that when formulated at an abstract level, problems from IR, from statistical data analysis, and from physical measurement theories are very similar and hence can profitably be cross-fertilised, and, secondly, to propose a novel method of fuzzy hierarchical clustering, termed \textit{semantic distillation} -- strongly inspired from the theory of quantum measurement --, we developed to analyse raw data coming from various types of experiments on DNA arrays. We illustrate the method by analysing DNA arrays experiments and clustering the genes of the array according to their specificity.Comment: Accepted for publication in Studies in Computational Intelligence, Springer-Verla

Estimation of the Bistable Zone for Machining Operations for the Case of a Distributed Cutting- Force Model

Regenerative machine tool chatter is investigated for a single-degree-of-freedom model of turning processes. The cutting force is modeled as the resultant of a force system distributed along the rake face of the tool, whose magnitude is a nonlinear function of the chip thickness. Thus, the process is described by a nonlinear delay-differential equation, where a short distributed delay is superimposed on the regenerative point delay. The corresponding stability lobe diagrams are computed and are shown numerically that a subcritical Hopf bifurcation occurs along the stability boundaries for realistic cutting-force distributions. Therefore, a bistable region exists near the stability boundaries, where large-amplitude vibrations (chatter) may arise for large perturbations. Analytical formulas are obtained to estimate the size of the bistable region based on center manifold reduction and normal form calculations for the governing distributed-delay equation. The locally and globally stable parameter regions are computed numerically as well using the continuation algorithm implemented in DDE-BIFTOOL. The results can be considered as an extension of the bifurcation analysis of machining operations with point delay

Validation of nonlinear PCA

Linear principal component analysis (PCA) can be extended to a nonlinear PCA by using artificial neural networks. But the benefit of curved components requires a careful control of the model complexity. Moreover, standard techniques for model selection, including cross-validation and more generally the use of an independent test set, fail when applied to nonlinear PCA because of its inherent unsupervised characteristics. This paper presents a new approach for validating the complexity of nonlinear PCA models by using the error in missing data estimation as a criterion for model selection. It is motivated by the idea that only the model of optimal complexity is able to predict missing values with the highest accuracy. While standard test set validation usually favours over-fitted nonlinear PCA models, the proposed model validation approach correctly selects the optimal model complexity.Comment: 12 pages, 5 figure

Defining the remarkable structural malleability of a bacterial surface protein Rib domain implicated in infection

Streptococcus groups A and B cause serious infections, including early onset sepsis and meningitis in newborns. Rib domain-containing surface proteins are found associated with invasive strains and elicit protective immunity in animal models. Yet, despite their apparent importance in infection, the structure of the Rib domain was previously unknown. Structures of single Rib domains of differing length reveal a rare case of domain atrophy through deletion of 2 core antiparallel strands, resulting in the loss of an entire sheet of the β-sandwich from an immunoglobulin-like fold. Previously, observed variation in the number of Rib domains within these bacterial cell wall-attached proteins has been suggested as a mechanism of immune evasion. Here, the structure of tandem domains, combined with molecular dynamics simulations and small angle X-ray scattering, suggests that variability in Rib domain number would result in differential projection of an N-terminal host-colonization domain from the bacterial surface. The identification of 2 further structures where the typical B-D-E immunoglobulin β-sheet is replaced with an α-helix further confirms the extensive structural malleability of the Rib domain

Modes of Foreign Entry under Asymmetric Information about Potential Technology Spillovers

This paper studies the effect of technology spillovers on the entry decision of a multinational enterprise into a foreign market. Two alternative entry modes for a foreign direct investment are considered: Greenfield investment versus acquisition. We find that with quantity competition a spillover makes acquisitions less attractive, while with price competition acquisitions become more attractive. Asymmetric information about potential spillovers always reduces the number of acquisitions independently of whether the host country or the entrant has private information. Interestingly, we find that asymmetric information always hurts the entrant, while it sometimes is in favor of the host country

Self-rated health in middle-aged and elderly Chinese : distribution, determinants and associations with cardio-metabolic risk factors

Background: Self-rated health (SRH) has been demonstrated to be an accurate reflection of a person's health and a valid predictor of incident mortality and chronic morbidity. We aimed to evaluate the distribution and factors associated with SRH and its association with biomarkers of cardio-metabolic diseases among middle-aged and elderly Chinese. Methods: Survey of 1,458 men and 1,831 women aged 50 to 70 years, conducted in one urban and two rural areas of Beijing and Shanghai in 2005. SRH status was measured and categorized as good (very good and good) vs. not good (fair, poor and very poor). Determinants of SRH and associations with biomarkers of cardio-metabolic diseases were evaluated using logistic regression. Results: Thirty two percent of participants reported good SRH. Males and rural residents tended to report good SRH. After adjusting for potential confounders, residence, physical activity, employment status, sleep quality and presence of diabetes, cardiovascular disease, and depression were the main determinants of SRH. Those free from cardiovascular disease (OR 3.68; 95%CI 2.39; 5.66), rural residents (OR 1.89; 95% CI 1.47; 2.43), non-depressed participants (OR 2.50; 95% CI 1.67; 3.73) and those with good sleep quality (OR 2.95; 95% CI 2.22; 3.91) had almost twice or over the chance of reporting good SRH compared to their counterparts. There were significant associations -and trend- between SRH and levels of inflammatory markers, insulin levels and insulin resistance. Conclusion: Only one third of middle-aged and elderly Chinese assessed their health status as good or very good. Although further longitudinal studies are required to confirm our findings, interventions targeting social inequalities, lifestyle patterns might not only contribute to prevent chronic morbidity but as well to improve populations' perceived health