• Journal of IKEEE
• /
• v.22 no.3
• /
• pp.590-598
• /
• 2018

Recently, interest in IoT(Internet of Things) technology, which provides Internet services to objects, is increasing. IoT offers a variety of services in home networks, healthcare, and disaster alerts. IoT with LLN(Low Power & Lossy Networks) feature frequently loses sensor node. RPL, the standard routing protocol of IoT, performs global repair when data loss occurs in a sensor node. However, frequent loss of sensor nodes due to lower sensor nodes causes network performance degradation due to frequent full path reset. In this paper, we propose an additional selection method of the storage mode sensor node to solve the network degradation problem due to the frequent path resetting problem even after selecting the storage mode sensor node, and propose a method of equalizing the total path resetting number of each instance.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.22 no.6
• /
• pp.114-123
• /
• 1985

This is the second part of the four-part paper describing the development of a packet-switched computer network named the cORNET In this paper, following the first par paper that describes the concepts of the KORNET and the development of the network management center (NMC), wc present the design of the KORNET and the development of the network node processor (NNP) The initial configuration of the KORNET consists of three NNP's and one NMC. We have developed each NNP as a microprocessor-based (Mc68000) multiprocessor system, and implemented the NMC using a super-mini computer (Mv/8000) For the KORNET we use the virtual circuit (VC) method as the packet service strategy and the distributed adaptive routing algorithm to adapt efficiently the variation of node and link status. Also, we use a dynamic buffer management algorithm for efficient storage management. Thc hardware of the NNP system has been designed with emphasis on modularity so that it may be expanded esily . Also, the software of the NNP system has been developed according to the CCITT recommendations X.25, X.3, X.28 and X.29.

• The Journal of the Korea Contents Association
• /
• v.13 no.9
• /
• pp.28-38
• /
• 2013

During the past decades, the B+-tree has been most widely used as an index file structure for disk-resident databases. For the disk based B+-tree, a node update can be cheaply performed just by modifying its associated disk page in place. However, in case that the B+-tree is stored on flash memory, the traditional algorithms of the B+-tree come to be useless due to the prohibitive cost of in-place updates on flash memory. For this reason, the earlier schemes for flash memory B+-trees usually take an approach that saves B+-tree changes from real-time updates into extra temporary storage. Although that approach can easily prevent frequent in-place updates in the B+-tree, it can suffer from a waste of storage space and prolonged search times. Particularly, it is not allowable to process range searches on the leaf node level. To resolve such problems, we devise a new scheme in which the leaf nodes and their parent node are stored together in a single flash block, called the p-node block.

• The KIPS Transactions:PartA
• /
• v.15A no.6
• /
• pp.325-334
• /
• 2008

Flash memory is widely used as a storage medium for mobile devices such as cell phones, MP3 players, PDA's due to its tiny size, low power consumption and shock resistant characteristics. Additionally, some computer manufacturers try to replace hard-disk drives used in Laptops or personal computers with flash memory. More recently, there are some literatures on developing a flash memory-aware $B^+$-tree index for an efficient key-based search in the flash memory storage system. They focus on minimizing the number of "overwrites" resulting from inserting or deleting a sequence of key values to/from the $B^+$-tree. However, in addition to this factor, the size of a physical page allocated to a node can affect the maintenance cost of the $B^+$-tree. In this paper, with diverse experiments, we compare and analyze the costs of construction and search of the $B^+$-tree and the space requirement on flash memory as the node size increases. We also provide sorting-based or non-sorting-based algorithms to be used when inserting a key value into the node and suggest an header structure of the index node for searching a given key inside it efficiently.

• The Journal of Society for e-Business Studies
• /
• v.14 no.1
• /
• pp.57-79
• /
• 2009

As the Web-based e-Business prevails, the volume of XML data on the Web is getting larger than ever. Although much research has been done on decomposing and storing XML data in RDB, which is now the most popular storage for XML, and on processing XML queries through their SQL counterparts, little attention was paid to how to alleviate the burden of storing massive volume of XML data. In this paper, we propose a hybrid method of storing XML data in RDB, whereby the unit of storage could be an XML subtree as well as an XML node. The part of XML data whose nodes were separately stored could be reformed into an XML subtree for storing when it gets rarely queried or less valuable for reference as time goes by. With this method, we designed and implemented a hybrid XML storage and query processing system, comparing it with the conventional system where an XML node is the only unit of storage. Through experiments, we compared storage efficiency and query processing performance, validating the effectiveness of our proposed system.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.12 no.1
• /
• pp.227-247
• /
• 2018

For intermittently connected wireless sensor networks deployed in hash environments, sensor nodes may fail due to internal or external reasons at any time. In the process of data collection and recovery, we need to speed up as much as possible so that all the sensory data can be restored by accessing as few survivors as possible. In this paper a novel redundant data storage algorithm based on minimum spanning tree and quasi-randomized matrix-QRNCDS is proposed. QRNCDS disseminates k source data packets to n sensor nodes in the network (n>k) according to the minimum spanning tree traversal mechanism. Every node stores only one encoded data packet in its storage which is the XOR result of the received source data packets in accordance with the quasi-randomized matrix theory. The algorithm adopts the minimum spanning tree traversal rule to reduce the complexity of the traversal message of the source packets. In order to solve the problem that some source packets cannot be restored if the random matrix is not full column rank, the semi-randomized network coding method is used in QRNCDS. Each source node only needs to store its own source data packet, and the storage nodes choose to receive or not. In the decoding phase, Gaussian Elimination and Belief Propagation are combined to improve the probability and efficiency of data decoding. As a result, part of the source data can be recovered in the case of semi-random matrix without full column rank. The simulation results show that QRNCDS has lower energy consumption, higher data collection efficiency, higher decoding efficiency, smaller data storage redundancy and larger network fault tolerance.

• Journal of Distribution Science
• /
• v.14 no.5
• /
• pp.107-114
• /
• 2016

Purpose - Loading can decrease the productivity due to the possibility of carrying out with the opposite order of storage in container terminal. When the container is to be taken out, it is needed to move the container stacked upon the container to be carried out to other place temporarily. It is called as rehandling. Remarshalling, with the loading plan, is the arranging the containers before the ship arrives in order to avoid the rehandling during the carrying out. The present study tried to find out the factors affecting the efficiency when building the remarshalling plan with the utilization of neighboring storage space as a outer slot, and analyzed the efficiency of several remarshalling algorithms with the combination of those factors. Research design, data and methodology - The present study used, when the remarshalling plan is prepared for utilizing the outer slot, the simulation methods in order to compare the efficiency of the remarshalling algorithms which made with the factors affecting the efficiency. The factors affecting the efficiency are the method of making the child node, method of arrangement, and possibility of application of FIX. In order to analyze the affecting factors on the efficiency, several algorithms are prepared with the combination of production of the child node and the arrangement method with the availability of FIX application. With this algorithm, the effect of the factors on the efficiency after building up of remarshalling plan with the target on the bay with 10 rows, 8 columns, and 10 indices. Results - The method of rearrangement and making of a child node as the factor affecting the efficiency of remarshalling utilization of the outer bay were studied. It is efficient to combine the method of making a child node with MCS in order to reduce the number of moving the containers. For reducing the time in carrying out, it was found that all arrangement methods should be combined with RCS for the efficiency. The result of experiment shows the application of FIX with good result in case of succession ratio. In addition, when FIX was not applied, all of the most combinations resulted in short time in remarshalling. As a result, it can be concluded that the algorithm with proper combination of making the child node and the arrangement can increase the job efficiency based on the importance. Conclusion - The present study suggested and analyzed the algorithms with the combination of the arrangement method, the making of child node, and FIX. It is needed to develop the algorithm to judge the possibility whether the best remarshalling plan can be built or not within the bay in order to find a better method between the two cases such as within the bay and outer the bay. As a method for extending the study on the factors affecting the efficiency, it is possible to find out the way to build the remarshalling plan within the permitted time under any storage situation.

• Korean Journal of Veterinary Research
• /
• v.31 no.4
• /
• pp.381-387
• /
• 1991

Deer hemal nodes were studied by gross anatomy and light microscopy. Hemal nodes were scattered in the periphery of thoracic and abdominal aortae, and spherical or avoid in shape. A hemal node consisted of a thin capsule and a hilum, and had numerous small subcapsular and deep sinuses distended by a great number of erythrocytes. Although a few lymphatic nodules and tissues were seen in the parenchyma, no typical cortex and medulla was defined. Blood vessels occurred, but lymph vessel was not observed in nodes. The parenchyma of the hemal node consisted of many erythrocytes and lymphocytes, and a few granulocytes, plasma cells megakaryocytes and macrophages. The stroma was composed of reticular cells and fibers. The capsule and trabecula was a collagenous connective tissue with smooth myofibers. The above findings suggest that the hemal nodes are involved in blood storage, blood filtration and immune reaction.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.31 no.6
• /
• pp.616-625
• /
• 2011

Ensuring the designed prestress force is very important for the safety of prestressed concrete bridge. The loss of prestress force in tendon could significantly reduce load carrying capacity of the structure. In this study, an automated prestress-loss monitoring system for prestressed concrete girder using PZT-interface and wireless impedance sensor node is presented. The following approaches are carried out to achieve the objective. Firstly, wireless impedance sensor nodes are designed for automated impedance-based monitoring technique. The sensor node is mounted on the high-performance Imote2 sensor platform to fulfill high operating speed, low power requirement and large storage memory. Secondly, a smart PZT-interface designed for monitoring prestress force is described. A linear regression model is established to predict prestress-loss. Finally, a system of the PZT-interface interacted with the wireless sensor node is evaluated from a lab-scale tendon-anchorage connection of a prestressed concrete girder.

• Journal of KIISE:Computer Systems and Theory
• /
• v.37 no.1
• /
• pp.55-59
• /
• 2010

Most applications for solar-powered wireless sensor networks are usually deployed in remote areas without a continuous connection to the external networks and a regular maintenance by an administrator. In this case, sensory data has to be stored in the network as much as possible until it is uploaded by the data mule. For this purpose, a balanced data distribution over the network should be performed, and this can be achieved efficiently by taking the amount of available energy and storage into account, in the system layer of each node. In this paper, we introduce a simple but very efficient data distribution algorithm, by which each solar-powered node utilizes the harvested energy and the storage space maximally. This scheme running on each node determines the amount of energy which can be used for a data distribution as well as the amount of data which should be transferred to each neighbor, by using the local information of energy and storage status.