Browsing by Subject "Consolidation"

Now showing 1 - 5 of 5

Open Access
Assortment planning considering split orders
(2021-08) Söylemez, Duygu
When multi-item orders cannot be satisﬁed through a single shipment stemming from not having all the items in an order in the same warehouse, the cost of packaging and transportation increases and the delivery of the orders can be delayed. In this regard, split order problem is one of the most signiﬁcant challenges that the online retailers face. As the capacities of the warehouses are limited, it is not possible to stock every item in every warehouse. To minimize the number of orders that cannot be satisﬁed in a single shipment, it is important to determine how the limited capacities of the warehouses should be allocated to items or it is necessary to decrease the transportation costs through consolidating the split orders. Since this problem is NP-hard, the previous studies in the literature are based on heuristic algorithms. In this study, exact and heuristic methods have been examined to solve large scale problems. Some of the heuristic algorithms oﬀered uses the LP relaxation of the model provided by Jehl et al.(2018). In this sense, the analytical characterization of the optimal solution of the LP relaxation has also been revealed. It is proved that the allocation variables can only take three diﬀerent values at most one being fractional. It is shown that this solution can be found without actually solving the LP relaxation by beneﬁting from an algorithm oﬀered in literature to solve 0-1 fractional programming problems. Moreover, it is proved that a similar characterization is preserved for multiple warehouses or when a central depot with unlimited capacity and a forward distribution center are considered together. Additionally, the working principle of the greedy ranking algorithm oﬀered in the literature is theoretically justiﬁed and a dynamic version of this algorithm is developed. To evaluate the performance of the heuristic algorithms oﬀered and the run time of the integer programming problem, an extensive numerical study has been conducted. The change in the diﬃculty level of the problem based on the plant capacity, the number of orders, and the number of stock keeping units (SKU) is scrutinized. Furthermore, the assortment allocation problem is modeled together with the consolidation problem. The performance of the model is evaluated through comparing its solution to the solution obtained through solving two problems consecutively.
Open Access
Asymptotic analysis of reliability for switching systems in light and heavy traffic conditions
(Birkhäuser, Boston, 2000) Anisimov, Vladimir V.; Limnios, N.; Nikulin, M.
An asymptotic analysis of flows of rare events switched by some random environment is provided. An approximation by nonhomogeneous Poisson flows in case of mixing environment is studied. Special notions of S-set and “monotone” structure for finite Markov environment are introduced. An approximation by Poisson flows with Markov switches in case of asymptotically consolidated environment is proved. An analysis of the 1st exit time from a subset is also given. In heavy traffic conditions an averaging principle for trajectories with Poisson approximation for flows of rare events in systems with fast switches is proved. The method of proof is based on limit theorems for processes with semi-Markov switches. Applications to the reliability analysis of state-dependent Markov and semi-Markov queueing systems in light and heavy traffic conditions are considered
Open Access
A survey on the use of vocabulary learning strategies of high school students
(2019-06) Derici, Elif
This study investigates the vocabulary learning strategies (VLSs) employed by 556 high school students to identify the most and least frequently used discovery and consolidation strategies. The study further investigates whether there is any difference between VLSs used with respect to gender, grade level, school type and age. To these ends, the researcher collected data through an adapted version of Schmitt‟s (1997) Vocabulary Learning Strategies Questionnaire (VLSQ) administering it in different types of schools, Anatolian high school, Private high school and Science high school. The researcher analyzed both discovery and consolidation strategies, including their sub-categories descriptively. The researcher also analyzed the collected data inferentially with reference to gender, grade level, school type and age. The analysis of the data yielded significant results.
Open Access
Trait anxiety and post-learning stress do not affect perceptual learning
(Elsevier, 2012) Aberg, K.; Clarke, Aaron; Sandi, C.; Herzog, M.
While it is well established that stress can modulate declarative learning, very few studies have investigated the influence of stress on non-declarative learning. Here, we studied the influence of post-learning stress, which effectively modulates declarative learning, on perceptual learning of a visual texture discrimination task (TDT). On day one, participants trained for one session with TDT and were instructed that they, at any time, could be exposed to either a high stressor (ice–water; Cold Pressor Test; CPT) or a low stressor (warm water). Participants did not know when or which stressor they would be exposed to. To determine the impact of the stressor on TDT learning, all participants returned the following day to perform another TDT session. Only participants exposed to the high stressor had significantly elevated cortisol levels. However, there was no difference in TDT improvements from day one to day two between the groups. Recent studies suggested that trait anxiety modulates visual perception under anticipation of stressful events. Here, trait anxiety did neither modulate performance nor influence responsiveness to stress. These results do not support a modulatory role for stress on non-declarative perceptual learning.
Open Access
Transformation of the Turkish military and the path to democracy
(Sage Publications, Inc., 2008-04) Satana, N. S.
Democratization scholars argue that Turkey has successfully transitioned to democracy and is consolidating liberal democracy. The political elite and the parties are deemed important factors in crafting democracies. However, the Turkish political leadership has not changed much until recently; therefore, it remains a puzzle why consolidation is taking place. There are two explanations: (1) there is no consolidation of democracy (2) a factor other than the turnover in political elite/change in the political system has led to consolidation. I argue that consolidation is in progress because of the lengthy but persistent transformation of the military in Turkey. I examine previously overlooked changes in Turkish military with respect to its structure and its relations to the society. I find that the change in the military contributes to the consolidation of democracy in Turkey, and other transitional democracies. As with any other institutional change, this process is slow and risky.