• Journal of the Korea Society of Computer and Information
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• v.4 no.3
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• pp.78-92
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• 1999

In mobile computing environments, to efficiently use the narrow bandwidth of wireless networks a mobile host caches the data that are frequently accessed. To guarantee the correctness of the mobile transaction, the data cached in a mobile host must be consistent with the data in a server. This paper proposes a new strategy which maintains cache consistency efficiently when the data cached in a mobile host are inconsistent with the data in a server by the mobility of the mobile host at the asynchronous mobile environment. In this strategy, the size of the invalidation message is relatively small and is independent of the number of data to be invalidated under conditions of variable update rates/patterns. So this strategy uses the narrow bandwidth of wireless networks efficiently and reduces the communication cost.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.2
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• pp.275-282
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• 2015

Since a NAND-flash memory is able to keep data during electricity-off and has small cost to store data per bytes, it is widely used on hand-held devices. It is necessary to use an index in order to process mass data effectively on the flash memory. However, since the flash memory requires high cost for a write operation and does not support an overwrite operation, it is possible to reduce the performance of the index when the disk based index is exploited. In this paper, we implement the fixed grid file index and evaluate the performance of the index on various conditions. To do this, we measure the average processing time by the ratio of query operations and update operations. We also the compare the processing times of the flash memory with those of the magnetic disk.

• The Journal of the Korean dental association
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• v.55 no.9
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• pp.640-656
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• 2017

Xerostomia is usually caused by a reduced salivary flow or by changes in the biochemical composition of saliva. Halitosis or oral malodor is an offensive odor usually originating from the oral cavity. Halitosis can lead to anxiety and psychosocial embarrassment. The occurrence of halitosis closely related with intraoral conditions including the presence of xerostomia. Especially, the relationship between xerostomia and halitosis is prominent in elderly patients receiving polypharmacy with at least two systemic diseases. This study is a review of the update literature of xerostomia and halitosis. A large number of papers have been searched and identified using the words , , , , , , and . Papers not relevant to the issue were removed reducing the entries to 79 only. Most of identified papers were systematic reviews, non-systematic reviews, and observational studies. With a proper diagnosis, identification of the etiology and timely referrals certain steps are taken to create a successful individualized therapeutic approach. It is significant to highlight the necessity of an interdisciplinary method for the treatment of xerostomia and halitosis to prevent misdiagnosis or unnecessary treatment. This article concisely focuses on the development of a systemic flow of events to come to the proper treatment of the xerostomia and halitosis.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.1
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• pp.42-48
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• 2003

To get a periodic trim solution from Level II helicopter flight dynamic equations, DAE based PPT A (partial Periodic Trimming Algorithm) has been proposed. Iterative update of state variables from PPT A can cause a numerical instability in DAE solver which needs compatible initial conditions. By simply adjusting the order of DAE solver a periodic trim can be obtained with good accuracy. Application for CBM (Common Baseline Model) helicopter showed the same trim result as harmonic balance method and the effective elimination of unrealistic initial responses at the start of flight simulation.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.4
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• pp.351-360
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• 2022

Autonomous vehicles require precise knowledge of their position, velocity and orientation in all weather and traffic conditions in any time. And, these information is effectively used for path planning, perception, and control that are key factors for safety of vehicle driving. For this purpose, a high precision GNSS technology is widely adopted in autonomous vehicles as a core localization and navigation method. However, due to the lack of infrastructure as well as cost issue regarding GNSS correction data communication, only a few high precision GNSS technology will be available for future commercial autonomous vehicles. Recently, a high precision GNSS sensor that is based on a Broadcast-RTK system to dramatically reduce network maintenance cost by utilizing the existing broadcasting network is released. In this paper, we present the performance test result of the broadcast-RTK-based commercial high precision GNSS receiver to test the feasibility of the system for autonomous driving in Korea. Massive measurement campaigns covering of Korea region were performed, and the obtained measurements were analyzed in terms of ambiguity fixing rate, integer ambiguity loss recovery, time to retry ambiguity fixing, average correction information update rate as well as accuracy in comparison to other high precision systems.

• Journal of Practical Agriculture & Fisheries Research
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• v.23 no.1
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• pp.105-115
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• 2021

In this paper, we surveyed the service system disclosed by the government and self-governing province to analyze the status of IoT data service. Survey conditions were focused on data generated from objects such as sensors, OpenAPI that can utilize the generated data and data having a data update cycle of less than 1 month. As a result of the survey, the ratio of IoT data to data released by the government, self-governing province and the private sector was only 1.2%. Therefore, in order to increase the utilization with the development of IoT technology, a dedicated organization that can manage the IoT data service is needed.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.4
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• pp.47-52
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• 2023

With the growing data size and the increased computing load in machine learning, energy-efficient resource planning in IoT systems is becoming increasingly important. In this paper, we suggest a new resource planning policy for real-time workloads that can be fluctuated over time in IoT systems. To handle such situations, we categorize real-time tasks into fixed tasks and variable tasks, and optimize the resource planning for various workload conditions. Based on this, we initiate the IoT system with the configuration for the fixed tasks, and when variable tasks are activated, we update the resource planning promptly for the situation. Simulation experiments show that the proposed policy saves the processor and memory energy significantly.

• IMMUNE NETWORK
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• v.22 no.1
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• pp.11.1-11.26
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• 2022

When epithelial cells are exposed to potentially threatening external stimuli such as allergens, bacteria, viruses, and helminths, they instantly produce "alarmin" cytokines, namely, IL-33, IL-25, and TSLP. These alarmins alert the immune system about these threats, thereby mobilizing host immune defense mechanisms. Specifically, the alarmins strongly stimulate type-2 immune cells, including eosinophils, mast cells, dendritic cells, type-2 helper T cells, and type-2 innate lymphoid cells. Given that the alarm-raising role of IL-33, IL-25, and TSLP was first detected in allergic and infectious diseases, most studies on alarmins focus on their role in these diseases. However, recent studies suggest that alarmins also have a broad range of effector functions in other pathological conditions, including psoriasis, multiple sclerosis, and cancer. Therefore, this review provides an update on the epithelium-derived cytokines in both allergic and non-allergic diseases. We also review the progress of clinical trials on biological agents that target the alarmins and discuss the therapeutic potential of these agents in non-allergic diseases.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.47 no.2
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• pp.116-123
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• 2024

In the manufacturing industry, dispatching systems play a crucial role in enhancing production efficiency and optimizing production volume. However, in dynamic production environments, conventional static dispatching methods struggle to adapt to various environmental conditions and constraints, leading to problems such as reduced production volume, delays, and resource wastage. Therefore, there is a need for dynamic dispatching methods that can quickly adapt to changes in the environment. In this study, we aim to develop an agent-based model that considers dynamic situations through interaction between agents. Additionally, we intend to utilize the Q-learning algorithm, which possesses the characteristics of temporal difference (TD) learning, to automatically update and adapt to dynamic situations. This means that Q-learning can effectively consider dynamic environments by sensitively responding to changes in the state space and selecting optimal dispatching rules accordingly. The state space includes information such as inventory and work-in-process levels, order fulfilment status, and machine status, which are used to select the optimal dispatching rules. Furthermore, we aim to minimize total tardiness and the number of setup changes using reinforcement learning. Finally, we will develop a dynamic dispatching system using Q-learning and compare its performance with conventional static dispatching methods.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.6
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• pp.1108-1112
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• 2011

Voice can be widely used to classify the four constitution types and to recognize one's health condition from extracting meaningful features as physical quantity in traditional Korean medicine or Western medicine. In this paper, we proposed the method to update the standard operating procedure (SOP) to acquire and record voices for extracting stable vocal features since they are sensitive to the variation of a subject's utterance. At first, we obtained pitch frequencies from vowels and the sentence and intensity form the sentence as features with voices acquired under subjects' utterance conditions and then the deviation ratios of features from median values according to the utterance conditions were obtained and the condition to minimize the ratio was selected as a new SOP. As a result, we decided the SOP for a subject to utter vowels with the length of 2s~1s and sentences with over 2s interval between them after practice, in consideration of the deviation and qualitative requirements. Stable voice features obtained from updated SOP produce accurate diagnosis, which will be developed and simplified for using in the u-Healthcare system of personalized medicine.