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The current Internet inherently has a degree of survivability due to the connection less IP Protocol. Dynamic routing Protocols are designed to react to faults by changing routes when routers learn about topology changes via routing information updates (e.g., link status advertisements). Loss of Quality of service (QoS) has not been an issue because current Internet traffic is the best-effort. On the contrary, the multi protocol label switching (MPLS) approach is connection-oriented, which implies greater potential vulnerability to faults. At the same time, MPLS will support integrated services, which are more sensitive to loss of service. Reliability is becoming more important as more users depend on the internet for critical communication services and expect a higher level of performance. Usually, fault recovery is attempted first at the lowest layer, and escalated to the next layer if recovery was unsuccessful or impossible. Fault recovery capabilities in the MPLS layer are needed as well to decouple MPLS from dependence on physical layer fault recovery mechanisms which may differ between networks. This paper proposes an enhanced-scheme for fast rerouting to pre-assigned label-switched paths (LSPs) in case of LSP or link failures. In order to minimize backup resources, it allows possibility of splitting traffic of faulty LSP onto available alternative LSPs for fault recovery. We use Pre-assigned backup LSPs for restoration, when fault occurs. Total traffic throughput and resource utilization can be maximized if the traffic of faulty LSP is split over multiple pre-assigned LSPs. In this paper a new approach to providing fault tolerance in MPLS networks using case-based reasoning (CBR) as a method to find out the amount of traffic forwarded on each pre-assigned LSP based on past experiences of loading process is presented. The pre-assigned LSPs and the percentage of traffic splitting are calculated off-line based on desired QoS and capacity constraints. Also we evaluate the operation of successful decomposition of traffic based on the two mentioned constraints by using CBR, when the number of backup LSPs as a complexity factor increase. In another point of view, in cases when there is no possibility of using the experiences successfully, there would be no other way than using the erroneous unsuccessful experiences. We thus solved our recovery problem by using, first incorrect databases in our experiments, to moving later towards decreasing the error rate in a gradual manner.

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The causation has a special and important role in the philosophy, especially traditional philosophy. Main question in this study is whether the description of causal relations in Islamic philosophy can be justified and explained in the framework of the theory of conceptual metaphor. The study is focused on theology section of Al-Shifa (Healing) written by Ibn Sina. The book of Al-Shifa (Healing) is one of the most important works of Ibn Sina. The theology section of this book should be considered as the most important philosophical work of Ibn Sina. To answer the question, conceptual metaphors of causation in this book are identified. Ibn Sina uses many different words to describe the causal relations. By extracting and categorization of those words, several conceptual metaphors about causation are found. In this study, the role and importance of every one of these conceptual metaphors is determined by statistical method. The statistical data is extracted by counting words related to source domain of conceptual metaphors.
Conceptual metaphors related to causation in the book can be divided into two major categories: metaphors based on the primary metaphor of “Cause Is Physical Force" and metaphors based on natural causation. By extracting the abundance of each of the two categories, it becomes clear that the metaphors based on natural causation have a greater frequency than another in the theology of Al-Shifa( Healing)
1. Introduction
In the theory of conceptual metaphors, George Lakoff and Mark Johnson claim that understanding of abstract concepts is made possible by understanding of less abstract concepts. Causation is one of important abstract concepts in traditional philosophy. Ibn Sina is one of the greatest Muslim philosophers and Al-Shifa is his most important philosophical book. The Al-Shifa includes the sections of logic, physics and theology. This research focuses on the theology section of this book.
 This study is about following basic questions by focusing theology section of Ibn sina’ Al-Shifa :
A) Can Ibn Sina's understanding and description of the causal relationship be explained in the framework of the theory of conceptual metaphors?
The hypothesis of this study is that Ibn Sina's understanding of causation can be explained by the theory of conceptual metaphors. Assuming that this hypothesis is true, other questions are raised in this study:
B) What are the important conceptual metaphors related to causation in the theology of Al-Shifa?
C) What is the importance and position of each of the above-mentioned conceptual metaphors in the theology of Al-Shifa?
The position and importance of each conceptual metaphor is determined by calculating the statistical frequency of each of these metaphors.
 
2. Literature review
For Aristotle, philosophy are the knowledge of the causes and principles of things (Aristotle: 981b-983a). He also believes that it is not possible to know objects without knowing their causes (Aristotle: 993b23, 983a24, 194b18). Ibn Sina, following the ideas of the first teacher, introduces philosophy as recognizing the principles and first causes of beings (Ibn Sina, 1376: 12).
Lakoff and Johnson introduce causation as one of the most important concepts to understand and describe the events in the human thought and language. They believe that the causation has been conceptualized by an initial skeletal literal structure, the central prototype, and finally the metaphorical extensions of this prototype (Lakoff & Johnson, 1980:71; 1999: 177‏-178).
They introduce several conceptual metaphors to describe causation focusing on everyday English language such as “Causation Is Forced Movements”, “Causation Is Transfer Of Possessions” , “Causation Is A Forced Change Of Shape” , “Causation Is Upward Motion” and “Causation Is Motion out” ‏(Lakoff, 1993: 220-229; Lakoff & Johnson, 1980: 69-76‏). They believe that the same conceptual metaphors of causation are also used in philosophical texts. Every philosophical theory of causation is based on one or more the conceptual metaphors. Every philosopher believes that only his view of causation is correct, but according to Lakoff and Johnson, none of these theories alone can represent all aspects of this concept ‏(Lakoff, 1999: 226).
 
3. Methodology
In conceptual metaphors, a conceptual domain - the target domain - is conceptualized by another conceptual domain - the source domain.
Conceptual metaphors in a text can be identified and introduced by relying on words related to source domain, or target domain, or combination of the two ( Stefanowitsch, 2006: 2-3‏). Target domain of all conceptual metaphors related to causation are words that literally mean causation. Although the Al-Shifa is full of descriptions of causal relationships, there are not many cases of using words that have a literal causal meaning. Therefore, in this study, the conceptual metaphors of causation in the Al-Shifa are extracted and introduced by words related to target domain of these metaphors. Every conceptual metaphor in the Al-Shifa is represented through the derivations of one or more lexical roots. This book is written in Arabic language.
By qualitative study of the theology section of the Al-Shifa, the most important conceptual metaphors related to causation in this book and the lexical roots related to each of these metaphors were extracted. Then, by counting the frequency of using derivatives of roots related to each of the conceptual metaphors in this book, the frequency of each of the conceptual metaphors in this book was calculated.
 
4. Conclusion
Some of the conceptual metaphors related to causation in Al-Shifa are similar to the conceptual metaphors introduced by Lakoff and Johnson, but the other part of these metaphors is new and original.
Conceptual metaphors in this book can be divided into two categories: (A) metaphors based on the primary metaphor "Cause Is Physical Force" and (B) metaphors based on natural causation. Category A includes metaphors that conceptualize causation as a kind of forced movement, while category B conceptualizes causation as an action or state that arises from the essence of an object and occurs automatically.
Category A includes “Causation Is Transfer Of Possessions”, “Causation Is Making” and “Causation Is Making An Impression” metaphors.
Category B includes “Causation Is Motion out”, “Causation Is Being Basis” and “Cause Is Source” metaphors.
“Causation Is Transfer Of Possessions” metaphor (108) is represented by the derivations of «‘-ṭ-w» (12), «w-h-b» (2) and « f-y-d » (94) roots. “Causation Is Making” metaphor (39) emerges through derivations of «j-‘-l» (30) and «ṣ-n-‘» (9) roots. “Causation Is Making An Impression” metaphor (59) related to the derivations of «‘- th-r»(59) root.
“Causation Is Motion out” metaphor (122) is represented by the derivations of «ṣ-d-r» (67), «n-sh-’» (2), «f-y-ḍ» (53) roots. “Causation Is Being Basis” metaphor (250) involves the derivations of «q-w-m» (250) root. “Cause Is Source” metaphor (317) is represented by the derivations of «b-d-’» (317) root.
The numbers in parentheses indicate the frequency of metaphoric usage of each lexical root or conceptual metaphors in theology section of Al-Shifa written by Ibn Sina.
Category B (689) has more frequency than Category A (206). This shows that Ibn Sina's philosophy is based on an essentialist view. In such a view, the events of the universe are the result of the inherent characteristics of beings, not the application of an external force on object.

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According to the cognitive theory of metaphor, conceptual metaphors are an integral part ‎of the human mind so that we can see these metaphors in all aspects of human thoughts and ‎actions. A part of these metaphors is shaped based on up/down spatial orientations. Based ‎on these metaphors, spatial orientations play a significant role in human understanding of ‎many abstract concepts. These orientational metaphors are visible in ordinary and natural ‎languages, as well as in specialized and scientific texts.  It is shown in this paper that a part ‎of these up-down orientational metaphors have also been used in Mullā Ṣadrā's philosophy: ‎the “Having Control or Force Is Up, Being Subject to Control or Force Is Down” metaphor ‎has been used to understand the causal relationship. The “Good Is Up and Bad Is Down” ‎metaphor makes understandable that the source of good attributes is in transcendent and ‎higher world and the source of bad attributes is in material and lowest world. The “More ‎Perfect Is Up and Less Perfect Is Down” metaphor has been used to understand the ‎gradational hierarchy of the beings.‎