228 research outputs found
An overview of cloud computing adoption across industries in a developing country
No full textThe purpose of the study is to investigate the nature of cloud computing adoption across different industries of Ghanaian organizations with the view of providing adoption trends and patterns for policy direction, practice and future research. A quantitative research approach consisting a survey of 305 Ghanaian organizations was adopted. The findings indicated the following. Firstly, the level of cloud computing adoption is low in Ghana. Secondly, information technology services, financial institutions, educational and telecommunication firms are the front runners in cloud computing adoption in Ghana. Thirdly, Ghanaian organizations tend to adopt software-as-a-service (SaaS) type of cloud service than infrastructure-as-a-service (IaaS) and platform-as-a-service (PaaS). Also, Ghanaian organizations tend to adopt private cloud deployment than hybrid, public and community. Lastly, cloud computing adoption is largely dominated by medium sized organizations. This study makes the following contribution to research and practice. First, it provides insight into cloud computing adoption trends and patterns across different industries in Ghana which arguable was non-existent. Second, this study has laid the foundation and provided direction for future research on cloud computing in Sub-Saharan Africa. Finally, this study contributes to practice by pointing out potential investment sectors for cloud computing business. It is therefore envisaged that these constructive and valuable findings contribute to the development of the cloud industry in Ghana as it is in its infancy
Undiagnosed Epileptic Case Since Childhood of Sturge-Weber Syndrome: First Case Report from Somalia
No full textSaid Abdi Mohamed,1 Nor Osman Sidow,1,2 Bakar Ali Adam,1 Mohamed Sheikh Hassan,1,3 Abdiwahid Ahmed Ibrahim,1 Mohamed Farah Osman,1 Abdulkadir Ahmed,1 Abdullahi Ali Roble4 1Department of Neurology, Mogadishu-Somalia Turkey Recep Tayyip Erdoğan Training and Research Hospital, Mogadishu, Somalia; 2Faculty of Medicine and Surgery, Jazeera University, Mogadishu, Somalia; 3Faculty of Medicine and Surgery, Mogadishu University, Mogadishu, Somalia; 4Department of Ophthalmology, Mogadishu-Somalia Turkey Recep Tayyip Erdoğan Training and Research Hospital, Mogadishu, SomaliaCorrespondence: Nor Osman Sidow, Tel +252618300616, Email [email protected]: Sturge-Weber syndrome is a rare, sporadic, progressive neurocutaneous condition that presents with congenital hamartomatous malformations, epilepsy, and a variety of facial symptoms. We discussed a rare case of an eighteen-year-old female child who came to our neurology department with status epilepticus, mental impairment, and a port-wine in the lateral left side of her face. We diagnosed Sturge-Weber syndrome after a thorough neurological and radiological evaluation. The purpose of presenting this case is to illustrate both the characteristic presentation and the complications associated with managing Sturge-Weber syndrome.Keywords: sturge-weber, seizure, port-win
Study of Radioclinical and Risk Factors of Cerebral Venous Thrombosis: A Retrospective Analysis of Patients Presenting to a Tertiary Hospital in Mogadishu, Somalia
No full textBakar Ali Adam,1,2 Ahmed Adam Osman,3 Mohamed Sheikh Hassan,1,2 Nor Osman Sidow,1 Mohamed Farah Osman Hidig,1 Abdulkadir Ahmed Mohamed,1 Abdiwahid Ahmed Ibrahim,1 Said Abdi Mohamed,1 Yahye Garad Mohamed,3 Said Abdirahman Ahmed,4 Mohamed Osman Omar Jeele,5 Mohamed Omar Hassan4 1Department of Neurology, Mogadishu Somali Turkish Training and Research Hospital, Mogadishu, Somalia; 2Faculty of Medicine and Surgery, Mogadishu University, Mogadishu, Somalia; 3Department of Radiology, Mogadishu Somali Turkish Training and Research Hospital, Mogadishu, Somalia; 4Department of Cardiology, Mogadishu Somali Turkish Training and Research Hospital, Mogadishu, Somalia; 5Department of Internal Medicine, Mogadishu Somali Turkish Training and Research Hospital, Mogadishu, SomaliaCorrespondence: Bakar Ali Adam, Email [email protected]: Cerebral venous thrombosis (CVT) is a rare but potentially life-threatening condition characterized by the formation of a blood clot in the dural venous sinuses or cerebral veins. CVT presents a diverse array of clinical symptoms, making its diagnosis challenging. Understanding regional variations and specific risk factors associated with CVT is crucial, especially in low-resource settings like Somalia, where epidemiological data is limited and healthcare resources are scarce.Objective: This study aims to investigate the clinical and risk factors associated with CVT in patients presenting to Mogadishu Somali-Turkey Recep Tayyip Erdogan Research and Training Hospital, a tertiary hospital in Mogadishu, Somalia.Methods: We conducted a retrospective observational study involving 68 patients diagnosed with CVT between January 2019 and December 2023. Data included demographic information, clinical presentations, risk factors, and anatomical thrombosis locations. Descriptive statistics and chi-square tests were used for analysis.Results: The majority of patients were female (86.76%) and aged 20– 40 years (86.76%). Significant risk factors included the postpartum period (77.94%) and pregnancy, with statistical analysis showing strong associations between CVT and the postpartum period (χ² = 62.96, p < 0.0001) and pregnancy (χ² = 5.21, p = 0.022). Postpartum CVT was linked to thrombosis location (p = 0.025). Headache was the predominant symptom (98.53%), followed by altered mental status (83.82%), focal motor deficits (80.88%), and seizures (70.59%). The superior sagittal sinus was the most commonly involved site (57.35%).Conclusion: This study emphasizes the postpartum period as a significant risk factor for CVT in Somalia and highlights the need for clinical vigilance and early intervention strategies. Larger, multicenter studies are needed to validate these findings.Keywords: cerebral venous thrombosis, CVT, postpartum, pregnancy, risk factors, Somalia, regional stud
Higher education in Egypt
No full textEgypt's policy on higher education, the author argues, must take account of the realities of declining government budgets and employment and increasing reliance on the private sector, which must become more competitive internationally. Education in Egypt must increase Egyptians'ability to cope with economic disequilibria: to respond quickly and effectively to changing technological and market opportunities. The Government of Egypt's strategy for achieving this goal is to stabilize the number of university students and raise the quality of instruction. This fundamentally sound strategy, pursued since the mid-1980s, has required considerable courage of policymakers, who are struggling to correct a longtime, inequitable misallocation of educational resources. The Nasser regime greatly expanded higher education and guaranteed jobs to university graduates. As a result of rapidly growing enrollment in the 1970s and 1980s, the quality of education seriously deteriorated. Classes are too big and resources too scarce for anything but professorial salaries, so learning amounts to little more than memorization and repetition. The system does not foster the development of synthesizing, problem-solving, or creative thinking abilities. And with tertiary institutions over-enrolled, academic success requires the use of tutors, whose fees are beyond the reach of students of modest means.Health Monitoring&Evaluation,Environmental Economics&Policies,Teaching and Learning,Gender and Education,Tertiary Education
Guided construction search metaheuristics for the capacitated p-median problem with single source constraint
No full textIn the capacitated p-median problem with single source constraint, also known as the capacitated clustering problem, a given set of n weighted points is to be partitioned into p clusters such that the total weight of the points in each cluster does not exceed a given cluster capacity. The objective is to find a set of p centres that minimizes the total scatter of points allocated to these clusters. In this paper, a (, )-interchange neighbourhood based on the concept of -interchange of points restricted to -adjacent clusters is proposed. Structural properties of centres are identified and exploited to derive special data structures for their efficient evaluations. Different search and selection strategies including the variable neighbourhood search descent with respect to -nearest points are investigated. The most efficient strategies are then embedded in a guided construction search metaheuristic framework based either on a periodic local search procedure or a greedy random adaptive search procedure to solve the problem. Computational experience is reported on a standard set of benchmarks. The computational experience demonstrates the competitive performance of the proposed algorithms when compared to the best-known procedures in the literature in terms of solution quality and computational requirement. © 2007 Operational Research Society Ltd. All rights reserved.Ahmadi S, 2004, ANN OPER RES, V131, P21, DOI 10.1023-B:ANOR.0000039511.61195.21; Ahmadi S, 2005, EUR J OPER RES, V162, P30, DOI 10.1016-j.ejor.2003.08.066; Baldacci R, 2002, COMPUT OPER RES, V29, P365, DOI 10.1016-S0305-0548(00)00072-1; BECK MP, 1982, EES821 PRINC U; Bellman R. E., 1957, DYNAMIC PROGRAMMING; Breedom AV., 2001, COMPUTER OPERATIONS, V28, P289, DOI 10.1016-S0305-0548(99)00101-X; Brucker P, 1977, OPTIMIZATION OPERATI, P45; CHHAJED D, 1993, LOCATION SCI, V1, P263; Chiang W, 1997, INFORMS J COMP, V9, P417, DOI 10.1287-ijoc.9.4.417; DIAZ JA, 2004, IN PRESS EUR J OPL R; DONGARRA J, 2005, CS8985 U TENN; Festa P, 2002, OPERAT RES COMP SCI, V15, P325; Franca P. M., 1999, International Transactions in Operational Research, V6, DOI 10.1016-S0969-6016(99)00017-9; GENDREAU M, 1992, OPER RES, V40, P1086, DOI 10.1287-opre.40.6.1086; Glover F., 1997, ADV METAHEURISTICS O, P1; Hansen P, 1997, MATH PROGRAM, V79, P191, DOI 10.1007-BF02614317; Hansen P, 2001, J HEURISTICS, V7, P335, DOI 10.1023-A:1011336210885; HANSEN P, 1994, EUR J OPER RES, V72, P602, DOI 10.1016-0377-2217(94)90427-8; HANSEN P, 1993, G9338; Hasan M., 1995, International Transactions in Operational Research, V2, DOI 10.1111-j.1475-3995.1995.tb00007.x; Karimi J., 1986, Journal of Management Information Systems, V3; KLEIN G, 1991, NAV RES LOG, V38, P447, DOI 10.1002-1520-6750(199106)38:3447::AID-NAV32203803123.0.CO;2-0; KOSKOSIDIS YA, 1992, TRANSPORT RES B-METH, V26, P365, DOI 10.1016-0191-2615(92)90032-R; Lorena LAN, 2004, COMPUT OPER RES, V31, P863, DOI 10.1016-S0305-0548(03)00039-X; Maniezzo V, 1998, J HEURISTICS, V4, P263, DOI 10.1023-A:1009665717611; MIRZAIAN A, 1985, NETWORKS, V15, P1, DOI 10.1002-net.3230150102; Hansen P, 2001, EUR J OPER RES, V130, P449, DOI 10.1016-S0377-2217(00)00100-4; MULVEY JM, 1984, EUR J OPER RES, V18, P339, DOI 10.1016-0377-2217(84)90155-3; Osman I. H., 1993, Annals of Operations Research, V41, DOI 10.1007-BF02023004; Osman I. H., 1994, INT T OPER RES, V11, P317, DOI 10.1111-1475-3995.d01-43; Osman Ibrahim H, 1996, METAHEURISTICS THEOR; Osman IH, 2003, COMPUT IND ENG, V44, P205, DOI 10.1016-S0360-8352(02)00175-4; OSMAN IH, 2005, P 6 MET INT C U VIEN, P725; Osman IH, 1995, OPERATIONAL RES TUTO, P92; OSMAN IH, 2004, P 5 AS PAC IND ENG M, P1; OSMAN IH, 1996, METAHEURISTICS THEOR, P1; Osman IH, 2003, COMPUT IND ENG, V45, P635, DOI 10.1016-j.cie.2003.09.005; Osman IH, 2006, COMPUT OPER RES, V33, P2526, DOI 10.1016-j.cor.2005.07.027; OSMAN IH, 1995, OR SPEKTRUM, V17, P211; Osman IH, 1996, ANN OPER RES, V63, P513; OSMAN IH, 2003, JOINT EURO INFORMS M; OSMAN IH, 2002, J SCHEDULING, V5, P265; PITSOULIS LS, 2002, HDB APPL OPTIMIZATIO, P168; RIBEIRO C, 2001, ESSAYS SURVEYS METAH; RUSSELL RA, 1995, TRANSPORT SCI, V29, P156, DOI 10.1287-trsc.29.2.156; SCHEUERER S, 2004, EUR J OPL RES, V169, P533; Steiglitz K., 1968, Proceedings sixth Allerton conference on circuit and system theory; Taillard E, 1997, TRANSPORT SCI, V31, P170, DOI 10.1287-trsc.31.2.170; Thangiah S.R., 1994, AM J MATH MANAGEMENT, V13, P323; Vakharia AJ, 2000, EUR J OPER RES, V123, P640, DOI 10.1016-S0377-2217(99)00103-4; VOSS S, 1998, METAHEURISTICS ADV T; Wassan NA, 2002, J OPER RES SOC, V53, P768, DOI 10.1057-palgrave.jors.260134411101
Density based problem space search for the capacitated clustering p-median problem
No full textIn the Capacitated Clustering Problem (CCP), a given set of n weighted points is to be partitioned into p clusters such that, the total weight of the points in each cluster does not exceed a given cluster capacity. The objective is to find a set of p centers that minimises total scatter of points allocated to them. In this paper a new constructive method, a general framework to improve the performance of greedy constructive heuristics, and a problem space search procedure for the CCP are proposed. The constructive heuristic finds patterns of natural subgrouping in the input data using concept of density of points. Elements of adaptive computation and periodic construction-deconstruction concepts are implemented within the constructive heuristic to develop a general framework for building efficient heuristics. The problem-space search procedure is based on perturbations of input data for which a controlled perturbation strategy, intensification and diversification strategies are developed. The implemented algorithms are compared with existing methods on a standard set of bench-marks and on new sets of large-sized instances. The results illustrate the strengths of our algorithms in terms of solution quality and computational efficiency.AHMAD I, 1995, CONCURRENCY-PRACT EX, V7, P411, DOI 10.1002-cpe.4330070506; AHMADI S, 2004, EUROPEAN J OPERA JAN; AHMADI S, 1998, THESIS U KENT CANTER; Baldacci R, 2002, COMPUT OPER RES, V29, P365, DOI 10.1016-S0305-0548(00)00072-1; BAXTER J, 1981, J OPER RES SOC, V32, P815, DOI 10.2307-2581397; BECK MP, 1982, EES821 PRINC U; Brucker P, 1977, OPTIMIZATION OPERATI, P45; CAPTIVO ME, 1991, EUR J OPER RES, V52, P65; CHHAJED D, 1993, LOCATION SCI, V1, P263; DHODHI MK, 1995, IEEE T COMPUT AID D, V14, P934, DOI 10.1109-43.402494; DONGARRA JJ, 2001, PERFORMANCE VARIOUS; Franca P. M., 1999, International Transactions in Operational Research, V6, DOI 10.1016-S0969-6016(99)00017-9; Franco J, 1997, CROP SCI, V37, P972; GENDREAU M, 1992, OPER RES, V40, P1086, DOI 10.1287-opre.40.6.1086; Glover F, 2000, CONTROL CYBERN, V29, P653; Hansen P, 1997, MATH PROGRAM, V79, P191, DOI 10.1007-BF02614317; HANSEN P, 1994, EUR J OPER RES, V72, P602, DOI 10.1016-0377-2217(94)90427-8; HANSEN P, 1993, G9338; Karimi J., 1986, Journal of Management Information Systems, V3; KLEIN G, 1991, NAV RES LOG, V38, P447, DOI 10.1002-1520-6750(199106)38:3447::AID-NAV32203803123.0.CO;2-0; KOSKOSIDIS YA, 1992, TRANSPORT RES B-METH, V26, P365, DOI 10.1016-0191-2615(92)90032-R; Leon VJ, 1997, IIE TRANS, V29, P115, DOI 10.1023-A:1018550624429; LEON VJ, 1995, OR SPEKTRUM, V17, P173; Liu G., 1968, INTRO COMBINATORIAL; Maniezzo V, 1998, J HEURISTICS, V4, P263, DOI 10.1023-A:1009665717611; MIRZAIAN A, 1985, NETWORKS, V15, P1, DOI 10.1002-net.3230150102; MULVEY JM, 1984, EUR J OPER RES, V18, P339, DOI 10.1016-0377-2217(84)90155-3; MURALIDHAR K, 1995, COMPUT OPER RES, V22, P701, DOI 10.1016-0305-0548(94)00063-E; Naphade KS, 1997, ANN OPER RES, V70, P307, DOI 10.1023-A:1018982423325; NEMHAUSER GL, 1988, WILEYINTERSCIENCE SE; Osman I. H., 1994, INT T OPER RES, V11, P317, DOI 10.1111-1475-3995.d01-43; Osman Ibrahim H, 1996, METAHEURISTICS THEOR; OSMAN IH, 2002, GUIDED CONSTRUCTION; Osman IH, 1995, OPERATIONAL RES TUTO, P92; OSMAN IH, 1995, OR SPEKTRUM, V17, P211; Osman IH, 1996, ANN OPER RES, V63, P513; OSMAN IH, 2003, JOINT EURO INFORMS M; Ribeiro CC, 2002, ESSAYS SURVEYS METAH; RUSSELL RA, 1995, TRANSPORT SCI, V29, P156, DOI 10.1287-trsc.29.2.156; Steiglitz K., 1968, Proceedings sixth Allerton conference on circuit and system theory; STORER RH, 1993, OPERATIONS RES PRODU; STORER RH, 1992, MANAGE SCI, V38, P1495, DOI 10.1287-mnsc.38.10.1495; Vakharia AJ, 2000, EUR J OPER RES, V123, P640, DOI 10.1016-S0377-2217(99)00103-4; VOSS S, 1998, METAHEURISTICS ADV T; WONG MA, 1982, J AM STAT ASSOC, V77, P841, DOI 10.2307-228731693
Greedy random adaptive memory programming search for the capacitated clustering problem
No full textIn the capacitated clustering problem (CCP), a given set of n weighted points is to be partitioned into p clusters such that, the total weight of the points in each cluster does not exceed a given cluster capacity. The objective is to find a set of p centers that minimises the total scatter of points allocated to these centers. In this paper, we propose a merger of Greedy Random Adaptive Search Procedure (GRASP) and Adaptive Memory Programming (AMP) into a new GRAMPS framework for the CCP. A learning process is kept in charge of tracking information on the best components in an elite set of GRAMPS solutions. The information are strategically combined with problem-domain data to restart the construction search phase. At early stage of constructions, priorities are given to problem-domain data and progressively shifted towards generated information as the learning increases. GRAMPS is implemented with an efficient local search descent based on a restricted λ-interchange neighbourhood. Extensive experiments are reported on on a standard set of bench-marks from the literature and on a new set of large instances. The results show that GRAMPS has an efficient learning mechanism and is competitive with the existing methods in the literature. © 2003 Elsevier B.V. All rights reserved.AHMADI S, 2004, ANN OPERATIONS RES M; AHMADI S, 1998, THESIS U KENT CANTER; AIEX RM, 2003, INFORMS J COMPUTING; Baldacci R, 2002, COMPUT OPER RES, V29, P365, DOI 10.1016-S0305-0548(00)00072-1; BECK MP, 1982, EES821 PRINC U; Brucker P, 1977, OPTIMIZATION OPERATI, P45; CHHAJED D, 1993, LOCATION SCI, V1, P263; DONGARRA JJ, 2001, PERFORMANCE VARIOUS; Dorigo M, 1996, IEEE T SYST MAN CY B, V26, P29, DOI 10.1109-3477.484436; FEO TA, 1989, OPER RES LETT, V8, P67, DOI 10.1016-0167-6377(89)90002-3; Fleurent C, 1999, INFORMS J COMPUT, V11, P198, DOI 10.1287-ijoc.11.2.198; Franca P. M., 1999, International Transactions in Operational Research, V6, DOI 10.1016-S0969-6016(99)00017-9; Glover F, 2000, CONTROL CYBERN, V29, P653; Glover F., 1977, DECISION SCI, V8, P156, DOI DOI 10.1111-J.1540-5915.1977.TB01074.X; Glover F., 1997, ADV METAHEURISTICS O, P1; Golden BL, 1997, COMPUT OPER RES, V24, P445, DOI 10.1016-S0305-0548(96)00065-2; Hansen P, 1997, MATH PROGRAM, V79, P191, DOI 10.1007-BF02614317; HANSEN P, 1994, EUR J OPER RES, V72, P602, DOI 10.1016-0377-2217(94)90427-8; HANSEN P, 1993, G9338; HANSEN P, 2002, ESSAYS SURVEYS METAH; Karimi J., 1986, Journal of Management Information Systems, V3; KLEIN G, 1991, NAV RES LOG, V38, P447, DOI 10.1002-1520-6750(199106)38:3447::AID-NAV32203803123.0.CO;2-0; KOSKOSIDIS YA, 1992, TRANSPORT RES B-METH, V26, P365, DOI 10.1016-0191-2615(92)90032-R; Laguna M, 1999, INFORMS J COMPUT, V11, P44, DOI 10.1287-ijoc.11.1.44; Maniezzo V, 1998, J HEURISTICS, V4, P263, DOI 10.1023-A:1009665717611; MIRZAIAN A, 1985, NETWORKS, V15, P1, DOI 10.1002-net.3230150102; MULVEY JM, 1984, EUR J OPER RES, V18, P339, DOI 10.1016-0377-2217(84)90155-3; Osman I. H., 1994, INT T OPER RES, V11, P317, DOI 10.1111-1475-3995.d01-43; Osman Ibrahim H, 1996, METAHEURISTICS THEOR; OSMAN IH, 2002, GUIDED CONSTRUCTION; Osman IH, 1999, LECT NOTES ARTIF INT, V1611, P11; Osman IH, 1995, OPERATIONAL RES TUTO, P92; Osman IH, 1996, ANN OPER RES, V63, P513; OSMAN IH, 2003, JOINT EURO INFORMS M; PITSOULIS LS, 2001, HDB APPL OPTIMIZATIO; Resende Festa P., 2001, ESSAYS SURVEYS METAH; Rochat Y., 1995, Journal of Heuristics, V1, DOI 10.1007-BF02430370; Vakharia AJ, 2000, EUR J OPER RES, V123, P640, DOI 10.1016-S0377-2217(99)00103-4; VOSS S, 1998, METAHEURISTICS ADV T30252
Paralytic Ileus as the Initial Presentation of Guillain–Barre Syndrome: A Rare Case Report
No full textMohamed Farah Osman Hidig,1 Mohamed Sheikh Hassan,1,2 Abdiwahid Ahmed Ibrahim,1 Bakar Ali Adam,1 Nor Osman Sidow,1 Said Abdi Mohamed1 1Department of Neurology, Mogadishu Somalia Turkish Training and Research Hospital, Mogadishu, Somalia; 2Faculty of Medicine and Surgery, Mogadishu University, Mogadishu, SomoliaCorrespondence: Mohamed Farah Osman Hidig, Department of Neurology, Mogadishu Somalia Turkish Training and Research Hospital, Mogadishu, Somalia, Email [email protected]: Emerging symmetrical limb weakness, altered sensory perception, and absent or reduced deep tendon reflexes are the hallmarks of Guillain-Barre syndrome (GBS). There are numerous studies that indicate up to two-thirds of patients with GBS may also have autonomic dysfunction. One uncommon presenting characteristic of GBS before motor weakness is evident is paralytic ileus, a sign of gastrointestinal dysautonomia. Here we describe the case of a 55-year-old man who was brought to the emergency room of our hospital with paralytic ileus, a less common symptom of early-stage GBS. The patient was initially treated with prokinetic drugs and total parenteral nutrition with no clinical improvement. The patient quickly developed ascending lower limb weakness that progressed to quadriplegia, which ultimately affected respiratory muscles, leading to respiratory failure requiring mechanical ventilation and intensive care unit hospitalization. A nerve conduction study showed demyelinating sensorimotor polyneuropathy. Analysis of cerebrospinal fluid revealed albumin-cytological dissociation. The patient was treated with intravenous immunoglobulin (IVIG) and other supportive treatments. Even though the patient’s enteral feeding support was uncomfortable due to a profound infection complicating lack of stomach emptying during the hospital stay, the patient passed away two months after being admitted. Lack of awareness about GBS gastrointestinal dysautonomia may cause delays in treatment initiation, and as a result, GBS may lead to life-threatening events. Reducing mortality and morbidity from GBS requires prompt diagnosis and treatment. This case reminds us that GBS may present as gastrointestinal dysautonomia.Keywords: Gullian-Barre syndrome, paralytic ileus, quadraparesis, intravenous immunoglobuli
Self-organizing feature maps for the vehicle routing problem with backhauls
No full textIn the Vehicle Routing Problem with Backhauls (VRPB), a central depot, a fleet of homogeneous vehicles, and a set of customers are given. The set of customers is divided into two subsets. The first (second) set of linehauls (backhauls) consists of customers with known quantity of goods to be delivered from (collected to) the depot. The VRPB objective is to design a set of minimum cost mutes; originating and terminating at the central depot to service the set of customers. In this paper, we develop a self-organizing feature maps algorithm, which uses unsupervised competitive neural network concepts. The definition of the architecture of the neural network and its learning rule are the main contribution. The architecture consists of two types of chains: linehaul and backhaul chains. Linehaul chains interact exclusively with linehaul customers. Similarly, backhaul chains interact exclusively with backhaul customers. Additional types of interactions are introduced in order to form feasible VRPB solution when the algorithm converges. The generated routes are then improved using the well-known 2-opt procedure. The implemented algorithm is compared with other approaches in the literature. The computational results are reported for standard benchmark test problems. They show that the proposed approach is competitive with the most efficient metaheuristics. © Springer Science + Business Media, LLC 2006.ANDRESOL R, 1999, META HEURISTICS ADV, P393; ANGENIOL B, 1988, NEURAL NETWORKS, V1, P289, DOI 10.1016-0893-6080(88)90002-0; Anily S, 1996, NAV RES LOG, V43, P415, DOI 10.1002-(SICI)1520-6750(199604)43:3415::AID-NAV73.0.CO;2-C; Aras N, 1999, NEURAL NETWORKS, V12, P1273, DOI 10.1016-S0893-6080(99)00063-5; BURKE LI, 1994, NEURAL NETWORKS, V7, P681, DOI 10.1016-0893-6080(94)90045-0; CASCO D, 1988, VEHICLE ROUTING METH, V16, P127; Chisman J. A., 1975, Computers and Operations Research, V2, DOI 10.1016-0305-0548(75)90015-5; Deif I., 1984, P BABS C SOFTW US TR, P75; DONGARRA JJ, 2002, PERFORMANCE VARIOUS; DURBIN R, 1987, NATURE, V326, P689, DOI 10.1038-326689a0; FISCHETTI M, 1992, MATH PROGRAM, V53, P173, DOI 10.1007-BF01585701; FORT JC, 1988, BIOL CYBERN, V59, P33, DOI 10.1007-BF00336888; GENDREAU M, 1992, OPER RES, V40, P1086, DOI 10.1287-opre.40.6.1086; Gendreau M, 1996, COMPUT OPER RES, V23, P501, DOI 10.1016-0305-0548(95)00036-4; Ghaziri H., 1996, METAHEURISTICS THEOR, P651; GHAZIRI H, 1991, ARTIFICIAL NEURAL NE, P829; Ghaziri H, 2003, COMPUT IND ENG, V44, P267, DOI 10.1016-S0360-8352(02)00179-1; Goetschalcicx M., 1993, MHRCTR8813 GEORG I T; GOETSCHALCKX M, 1989, EUR J OPER RES, V42, P39, DOI 10.1016-0377-2217(89)90057-X; Golden B., 1985, P 21 ANN M SE TIMS M, P90; JONGENS K, 1985, EUR J OPER RES, V19, P68, DOI 10.1016-0377-2217(85)90309-1; KALANTARI B, 1985, EUR J OPER RES, V22, P377, DOI 10.1016-0377-2217(85)90257-7; KENNEDY P, 1998, RISC BENCHMARK SCORE; KOHONEN T, 1982, BIOL CYBERN, V43, P59, DOI 10.1007-BF00337288; Kohonen T., 1995, SELF ORG MAPS; Laporte G, 1995, ANN OPER RES, V61, P227, DOI 10.1007-BF02098290; LOOI CK, 1992, COMPUT OPER RES, V19, P191, DOI 10.1016-0305-0548(92)90044-6; LOTKIN FCJ, 1978, EUROPEAN J OPERATION, V3, P135; MLADENOVIC N, 2001, COMMUNICATION; Mladenovic N, 1997, COMPUT OPER RES, V24, P1097, DOI 10.1016-S0305-0548(97)00031-2; Modares A., 1999, International Transactions in Operational Research, V6, DOI 10.1111-j.1475-3995.1999.tb00175.x; MOSHEIOV G, 1994, EUR J OPER RES, V79, P299, DOI 10.1016-0377-2217(94)90360-3; OSMAN IH, 2002, J SCHEDULING; Osman IH, 1995, OPERATIONAL RES TUTO, P92; Osman IH, 1996, ANN OPER RES, V63, P513; Peng MK, 1996, NEURAL NETWORKS, V9, P1241, DOI 10.1016-0893-6080(96)00017-2; Potvin J.-Y., 1993, ORSA Journal on Computing, V5; POTVIN JY, 1995, NEUROCOMPUTING, V8, P125, DOI 10.1016-0925-2312(94)00012-H; Potvin J.-Y., 1996, METAHEURISTICS THEOR, P619; REFETOFF S, 1990, THYROID TODAY, V13, P1; Renaud J, 2000, COMPUT OPER RES, V27, P905, DOI 10.1016-S0305-0548(99)00066-0; Smith KA, 1999, INFORMS J COMPUT, V11, P15, DOI 10.1287-ijoc.11.1.15; HOPFIELD JJ, 1985, BIOL CYBERN, V52, P141; Thangiah SR, 1996, COMPUT OPER RES, V23, P1043, DOI 10.1016-0305-0548(96)00018-4; Toth P., 1996, ADV METHODS TRANSPOR, P585; Toth P, 1999, EUR J OPER RES, V113, P528, DOI 10.1016-S0377-2217(98)00086-1; Toth P, 1997, TRANSPORT SCI, V31, P372, DOI 10.1287-trsc.31.4.372; Vakhutinsky A. I., 1995, Journal of Heuristics, V1, DOI 10.1007-BF02430366; YANO CA, 1987, INTERFACES, V17, P52, DOI 10.1287-inte.17.2.5216121
Abdurrahman Hibri Efendi , Defter-i Ahbar (Transkripsiyon ve değerlendirme)
No full textTarafımızca transkripsiyonu yapılmış bulunan Abdurrahman Hibrî Efendinin, Defter-i Ahbâr adlı eseri kuruluşundan 1058/ 1648 yılına meydana gelen olayları anlatmaktadır. Eser, esas olarak 1027/ 1618 - 1058/ 1648 yılları arasında dönemi tafsilatlı olarak anlatmaktadır. Üç nüshasını tespit ettiğimiz bu eser olarak hazırlanmıştır. Eserin tespit edilmiş üç nüshası bulunmaktadır. Esas olarak tezde kullandığımız nüsha Bayezid Devlet Kütüphanesi, Veliyyüddin Efendi, nr. 2418'dir. Eser 73 varak olup, ağdalı olmayan bir Türkçe ile yazılmıştır. Müellif, eserinde yer yer Arapça ve Farsça şiirlerle kullanmıştır. Defter-i Ahbâr, altı defter ve hatime üzerine bina edilmiştir. Birinci defterde, Osman Gazi'den başlayarak, Sultan I. Ahmed devrine kadar olan olayları muhtasar bir şekilde anlattıktan sonra İkinci defterden itibaren kendi yaşadığı dönem olan Sultan II. Osman, Sultan IV. Murad ve Sultan I. İbrahim devri olaylarını tafsilatlı olarak anlattıktan sonra Sultan I.İbrahim'in hal' edilişi ile son bulmaktadır. Eserde, Sultan II. Osman, Sultan IV. Murad ve Sultan I. İbrahim devrinde meydana gelen siyasî, iktisadî ve sosyal olaylara değinilmiştir. Müellif, eserinde yer alan olayların birçoğuna şahittir. Eserde verilen tarihler müellifin yaşadığı döneme denk gelmektedir. Müellif, olayları anlatırken alıntı yapmadan kendi müşahade ettiği hadiseleri zikretmiştir. Müellifin kaynak belirtmeden kendi müşahadelerine dayandırmasına rağmen başka eserlerden yararlandığı kanaatindeyiz. Sonuç olarak; Hibrî Efendinin Defter-i Ahbâr isimli eserin 1618-1648 yıllarını içine alan kısmı dikkatlice tetkik edilecek olursa tarihçilerin her zaman müracaat edebileceği birinci elden kaynak konumundadır.The book Defter-i Ahbar ( The Book of News ) by Abdurrahman Hibri Efendi, which is transcripted in this thesis, narrates the events from the foundation of the ottomon Empire to the year 1648 ( 1058 ) briefly. Especially the period between 1618 ( 1027 ) and 1648 ( 1058 ) is told in detail. This work is produced as a M.A. thesis based on Defter-i Ahbar. There are three boks which are found out. The copy used as the source is Veliyyüddin Efendi , nr. 2418 in the Bayezid Library. The book consists of 73 sheets, and it is written in a simple Turkish. The author made the book more fluent by using Persian and Arabic poems. Defter-i Ahbar is composed of six books and a conclusion part. İn the first book, the incidents starting from Osman Gazi until the period of Sultan Ahmed I are narrated briefly. ln the other parts, the author tells the periods of Sultan Osman II, Sultan Murad IV and Sultan İbrahim I when he lived, and he finishes the book with the dethroning Sultan İbrahim I . He mentions political, economical and social events in the reign of Sultan Osman II, Sultan Murad IV and Sultan İbrahim I . The author, directly, observed most of the events in the book. The period of the events is the some as the author's period. When he narrates the events, he doesn't make quotations; instead he mentions his own observations. Although he doesn't mention any sources, it is obvious that he used other Works. As a conclusion, Defter-i Ahbar by Hibri Efendi is a use ful primary source for historians because of the part which contains the years 1618 and 1648
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