• The Journal of the Korea Contents Association
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• v.11 no.4
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• pp.18-26
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• 2011

According that smart phones have been widely used, their users can easily access various information around the devices through location information services equipped to the smart phone devices. In this paper, we propose a WeWhere which is a system of client-server model for providing the current location among several smart phone users in real time. A client-side smartphone user send to a server his/her current location obtained by applying location information service provided from smart phones and receive location information of all smartphone users connected to the user from the server. The all location information is displayed on a smartphone of a user in client-side and users can track location of their related users. All most 200,000 persons in the world have used the proposed system, WeWhere, normally without overloading of a server system.

• Journal of Internet Computing and Services
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• v.19 no.5
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• pp.97-105
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• 2018

In this paper, we present our recent effort on the development of a portable OCS system (SCH-mOCS), which provides minimal but essential functionalities of conventional OCS systems. SCH-mOCS is targeted for the environment where Internet connection is not available and fast processing of essential patient information is needed. The main usage could be found at the outdoor environment, such as voluntary medical services at challenged regions. The target of the first usage of the system is in the rural area of Cambodia where medical service and ICT infrastructure is poor. We have been conducting voluntary medical services for 15 years in Cambodia, where the services usually run for 3 days and include outpatient diagnosis/consultation, medication, and simple surgeries. This medical service started in 2002, where about 20 SoonChunHyang University Bucheon Hospital staffs (doctors, nurses, and pharmacists) participated. We realized that a system like SCH-mOCS is needed: we have to consult many patients in a short period, so that a prompt response and prescription to the patients are very important. However, the conventional OCS system is not suitable, because the service is usually conducted outdoor environment where Internet connected computers cannot be installed. Moreover, since the service needs only a subset of the conventional hospital information system and fast system response, application of a full OCS is not practical. The adequate system is a bare minimal OCS system, with very simple and quickly manageable patient admission, consultation, and prescription functionalities. In this paper, we describe hardware as well as the software aspect of a mini-OCS we have developed for the purpose. We named the system SCH-mOCS (SoonChunHyang mini-OCS). We also describe the usage scenario of SCH-mOCS in order to demonstrate that the system is general enough to apply for other similarly challenged regions.

• Management Science and Financial Engineering
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• v.15 no.2
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• pp.69-100
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• 2009

In this paper, we consider a relatively new two-machine flow shop scheduling problem where the unit time WIP cost increases as a job passes through various stages in the production process, and the objective is to minimize the total WIP (work-in-process) cost. Specifically, we study three special cases of the problem. First, we consider the problem where processing times on machine 1 are identical. Second, the problem with identical processing times on machine 2 is examined. The recognition version of the both problems is unary NP-complete (or NP-complete in strong sense). For each problem, we suggest two simple and intuitive heuristics and find the worst case bound on relative error. Third, we consider the problem where the processing time of a job on each machine is proportional to a base processing time. For this problem, we show that a known heuristic finds an optimal schedule.

• Genomics & Informatics
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• v.10 no.4
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• pp.220-225
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• 2012

Recent rapid advances in genetic research are ushering us into the genome sequence era, where an individual's genome information is utilized for clinical practice. The most spectacular results of the human genome study have been provided by genome-wide association studies (GWASs). This is a review of the history of GWASs as related to my work. Further efforts are necessary to make full use of its potential power to medicine.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.119-122
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• 2005

In this paper, we investigated the recognition range according to modulation index for the ISO(International Standards Organization) 14443 13.56MHz contactless Type B RFID(Radio Frequency IDentification) system. We measured recognition range with changing modulation index step by step from 5% to 24% where we used 4 samples of Type B transponder with different resonance frequencies between 13.838MHz and 17.200MHz. While gradually increasing a distance in vertical direction from the center of the reader antenna, we measured the distance where the transponder's PUPI(Pseudo Unique PICC(Proximity IC Card) Identifier) is recognized continuously during 10 seconds and the distance where the transponder's PUPI is recognized at least two times during 5 seconds. From the measurement results, we found that the best recognition ranges were achieved when the reader had modulation index between 11% and 14%.

• The Korean Journal of Applied Statistics
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• v.25 no.4
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• pp.543-552
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• 2012

Parrondo paradox is a counter-intuitive phenomenon where two losing games can be combined to win or two winning games can be combined to lose. When we trade stocks with a history-dependent Parrondo game rule (where we buy and sell stocks based on recent investment outcomes) we found Parrondo paradox in stock trading. Using stock data of the KRX from 2008 to 2010, we analyzed the Parrondo paradoxical cases in the Korean stock market.

• Kyungpook Mathematical Journal
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• v.62 no.4
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• pp.769-772
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• 2022

Given a prime number p and a natural number m not divisible by p, we propose the problem of finding the smallest number r₀ such that for r ≥ r₀, every group G of order p^rm has a non-trivial normal p-subgroup. We prove that we can explicitly calculate the number r₀ in the case where every group of order p^rm is solvable for all r, and we obtain the value of r₀ for a case where m is a product of two primes.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.537-543
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• 1999

While there are to estimating design discharge , we are in trouble with how to separate area, Because discharges will be different depending on the shape of area even though there are same size of area . This study is for a reasonable presentation of design discharge method where there are changing characteristcs of area with SCS and Clark theory by sung HEC-1 Model. While we were Estimating desgin discharge with separating area in a relation to Time of Concentration(Tc) with SCS , Clark method, we found that if there are no variation of Tc the value of a discharge is not changed where shapes of area are different though. And from the result of analysis with SCS and Clark method, we ascertained that discharge by the SCS method was more bigger than that of the Clark where Area is less than 100ha. On the other hand, Clark method is more bigger in the more 1000ha.

• Kyungpook Mathematical Journal
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• v.63 no.2
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• pp.167-173
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• 2023

Let G be a finite group and let ν(G) be the probability that two randomly selected elements of G produce a nilpotent group. In this article we show that for every positive integer n > 0, there is a finite group G such that ${\nu}(G)={\frac{1}{n}}$. We also classify all groups G with ${\nu}(G)={\frac{1}{2}}$. Further, we prove that if G is a solvable nonnilpotent group of even order, then ${\nu}(G){\leq}{\frac{p+3}{4p}}$, where p is the smallest odd prime divisor of |G|, and that equality exists if and only if $\frac{G}{Z_{\infty}(G)}$ is isomorphic to the dihedral group of order 2p where Z_∞(G) is the hypercenter of G. Finally we find an upper bound for ν(G) in terms of |G| where G ranges over all groups of odd square-free order.

• Bulletin of the Korean Mathematical Society
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• v.33 no.3
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• pp.477-480
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• 1996

Let $\pi : Z \longrightarrow Y$ be a fiber bundle where Y and Z are compact Riemannian manifolds without boundary. We are primarily interested in the case where $\pi$ is a Riemannian submersion with minimal fibers; this is the case, for example, where Z is the sphere bundle of some vector bundle over Y or where Z is a principal bundle over Y.