فهرست مطالب یاسر سهرابی

VLSI technology is currently dealing with a serious challenge, as the exponential growth of density in VLSI and CMOS chips has reached its limit. Power dissipation in VLSI chip refers to heat generation, which is a real barrier against traditional CMOS technology. Irreversible logic leads to problems such as energy dissipation, heat generation, information loss and slow computations. We need a new technology for solving these problems. Using reversible logic can help solve this problem. In next generation of optical computers, electrical circuits and wires will be replaced by several optical fibers and these systems will be more efficient because they will be cheaper, lighter, and more compact without interference. Based on optical computations, several optical switches have been proposed for future applications. One of these switches is the Mach-Zehnder switch. Its behavior and the reversible circuits, which can be made with this switch is studied in this article. Finally, we introduce and design three new all-optical reversible gates named NFT, SRK and MPG, which are effective in designing all-optical reversible logical circuits such as flip-flops and other all-optical reversible sequential circuits. We also simulate one all-optical reversible circuits implemented with Mach-Zehnder switch and provide simulation challenges and solutions to overcome these challenges.

The authority of a captain is not limited to the technical management of the ship during the voyage and the administrative duties concerning the interaction with the administrative organizations located in commercial ports. The captain has, moreover, a special place arising from his role in the maritime trade scene and his role in managing the ship that allows him  to act on behalf of the maritime carriers in the transaction or to take other necessary measures in crew recruitment, ship repair, fulfillment of basic needs, etc. in emergencies where the completion of the voyage is subject to prompt action by the captain. The captain's authority is sometimes deemed to stem from the legitimate and conventional appearance and, consequently, from the reasonable perception created for others. However, he does not have such authority in reality. So, the question arises as to whether the shipowner's defense that captain has acted beyond his authority, if proven, is admissible and precludes the legitimate expectations of the other party to the contract about the owner’s commitment to the consequences of the captain’s acts. In other words, can the captain's authority be extended and can he be considered the shipowner’s agent? In response to this question, legal doctrine and jurisprudence have suggested the apparent agency of the captain in support of third parties in good faith who deal with the captain by trusting in the appearance and considering his authoritativeness. In this study, this type of agency of the captain in his interventions is examined in the domestic and foreign legal system. The results indicate that the apparent agency of the captain is represented mainly in his transactions such as ship sales and mortgages, cargo sales and mortgages, ship rental, crew recruitment, and bill of lading. The apparent agency leads to the liability of the ship owner making him responsible for fulfilling obligations arising from the acts of the apparent agent. Although the advancement of knowledge and the development of communication tools in recent years have made it possible to communicate with the owner and ask him for instructions, the notion of the impossibility of extraordinary intervention of the captain as an apparent agent is hardly acceptable. Accordingly, the legal doctrine today emphasizes the apparent agency of the captain, focusing on his specific role and scope of authority as one of the major bases of the apparent agency. In line with the legal literature, the rulings of foreign courts on a variety of issues uphold the captain's authority to steer ships from the port of loading to the port of discharge. The captain's intervention on behalf of the shipowner is sometimes expanded to the point where court documents are sent to him rather than to the owner or even where he is considered a defendant himself, and sparing him from this status is ruled to be void. Although the legal systems has  come to hold the view that the captain lacks the authority to sell the ship, his authority in mortgaging the ship and cargo is a point of contention, each legal system having  its own position, with minor disagreements within each system. Following Article 28 of the Iranian Amendment to the Maritime Act approved on 9/18/2012, which has replaced Article 89 of the Iranian Maritime Act, obtaining permission from the shipowner, the sender and the cargo owner is a necessary condition for mortgaging the ship. Although the legislature may appear to want to reduce the captain's authority and, consequently, to strip him of his apparent agency, according to the Paragraph A of the above-mentioned article, the captain is still eligible to receive a loan if necessary funds are not provided by the owner or in necessities when urgent interventions are necessary. Moreover, according to Article 33 of the Amendment to the Maritime Act, which has replaced Article 94 of the Maritime Act, the deficiency of the latter, which failed to determine the legal status of the unjustified sale of the cargo, has been eliminated, and by confirming its validity, the apparent agency of the captain in the sale of cargo has been explicitly acknowledged.This agency can also be sustained in concluding a lease in the event of an emergency. Besides, due to the special place of the ship certificate of registry in establishing the ownership in some legal systems such as the French Law, if the tenant's name is not mentioned in the bill of lading, the owner, being named in the ship certification of registry, is considered responsible for the captain's obligations. The apparent agency of the captain in issuing the bill of lading now enjoys an almost consensual endorsement among legal systems of the world.

This paper has studied the principle of freedom in one sided (unilateral) contracts in law of Iran and imamiyyah Jurisprudence. The present research has confronted with this question if the principle of freedom in one sided (unilateral) contracts is accepted by the law of Iran and Islamic jurisprudence or not and to where the realm of free Will effectiveness is. To answer this question, it should be stated that one sided free-will is restricted to identified (specific) ones sided (unilateral) contracts (Iq’aa) in the realm of non-financial rights. But in the scope of financial rights and in the area of objective rights, the principle of freedom in one sided (unilateral) contracts should be carried out in the ownership of actions (neither forbidden nor recommended-mubah), but the ownership of third party property (the ownership of property is for another person) is specified to pre-emption (shufa’a). One sided conveyance (transferring property from one owner to another) is specified to Will (Wasiyyat) and it is not a common rule. In contrast, abandonment (the surrender, relinquishment, disclaimer, or cession of property or of rights) is from of real rights according to the rule. it is impossible the establishment of one sided obligation for himself and for the benefit of the other in personal rights and creating obligation for the loss of the other is specific to guardianship established by will but legal release of obligation Is accorded with the rule. Finally, it is suggested that the civil legislature specifies an independent chapter to the basic provisions of the validity of one sided (unilateral) contracts and common rules and determines rules and definite (identified) effects of one sided (unilateral) contracts.