Intelligent Decision Support Algorithm for Uncertain Inventory Management

Le Ngoc Bao Long,Sam-Sang You,Truong Ngoc Cuong,Hwan-Seong Kim 한국항해항만학회 2023 한국항해항만학회 학술대회논문집 Vol.2023 No.1

This paper discovers a robust managerial strategy for a stochastic inventory of perishable products, where the model experiences changing factors including inner parameters and an external disturbance with unknown form. An analytical solution for the optimization problem can be obtained by applying the Hamilton-Bellman-Jacobi equation, however the policy result cannot completely suppress the oscillation from the external disturbance. Therefore, an intelligent approach named Radial Basis Function Neural Networks is applied to estimate the unknown disturbance and provide a robust controller to manipulate the inventory level more effective. The final results show the outstanding performance of RBFNN controller, where both the estimation error and control error are guaranteed in the predefined limit.

Dimension Estimation for Cargo using Image Segmentation and Edge Detection

Le Ngoc Bao Long,Sam-Sang You,Truong Ngoc Cuong,Hwan-Seong Kim 한국항해항만학회 2024 한국항해항만학회 학술대회논문집 Vol.2024 No.5

QoS-Aware and Energy-Efficient Resource Management in OFDMA Femtocells

Long Bao Le,Niyato, D.,Hossain, E.,Dong In Kim,Dinh Thai Hoang IEEE 2013 IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS Vol.12 No.1

<P>We consider the joint resource allocation and admission control problem for Orthogonal Frequency-Division Multiple Access (OFDMA)-based femtocell networks. We assume that Macrocell User Equipments (MUEs) can establish connections with Femtocell Base Stations (FBSs) to mitigate the excessive cross-tier interference and achieve better throughput. A cross-layer design model is considered where multiband opportunistic scheduling at the Medium Access Control (MAC) layer and admission control at the network layer working at different time-scales are assumed. We assume that both MUEs and Femtocell User Equipments (FUEs) have minimum average rate constraints, which depend on their geographical locations and their application requirements. In addition, blocking probability constraints are imposed on each FUE so that the connections from MUEs only result in controllable performance degradation for FUEs. We present an optimal design for the admission control problem by using the theory of Semi-Markov Decision Process (SMDP). Moreover, we devise a novel distributed femtocell power adaptation algorithm, which converges to the Nash equilibrium of a corresponding power adaptation game. This power adaptation algorithm reduces energy consumption for femtocells while still maintaining individual cell throughput by adapting the FBS power to the traffic load in the network. Finally, numerical results are presented to demonstrate the desirable operation of the optimal admission control solution, the significant performance gain of the proposed hybrid access strategy with respect to the closed access counterpart, and the great power saving gain achieved by the proposed power adaptation algorithm.</P>

Discrete stochastic EOQ model for deteriorating inventory in supply chain using Hamilton-Jacobi-Bellman equation

Long Le Ngoc Bao,Sam-Sang You,Hwan-Seong Kim 한국마린엔지니어링학회 2024 한국마린엔지니어링학회지 Vol.48 No.1

The Belt and Road Initiative (BRI): Opportunities and Risks from Vietnamese Perspective

Long Duc Bao NGUYEN,Tracy Trang LY,Doan Cong TRAN,Ai Van TRAN,An Quoc LE,Alan HUDSON 한국유통과학회 2022 The Journal of Asian Finance, Economics and Busine Vol.9 No.4

The goal of this research is to look at the Belt and Road Initiative’s (BRI) goals, principles, and priorities, as well as criticisms and concerns. Another goal is to determine the Vietnamese government’s best response to the BRI. Finally, the study looks at the Vietnamese viewpoint. Document review is used in conjunction with PESTELED analysis and EIU country risk model technique in this study. The study is focused on in-depth interviews with 38 top government leaders, researchers, and scholars by adopting the Delphi technique to determine major factors of risks and opportunities as well as obtain a clearer view on the Vietnamese perspective of the BRI. The main conclusion is that Vietnam’s participation in the BRI could result in a variety of benefits and risks, including economic development, connectivity and integration, development finance, cooperation, coordination, trade facilitation, and people-to-people communication, as well as diplomatic and political risks, financial risks, environmental challenges, and job creation. Another conclusion is suggested that careful and case-by-case negotiation with China is needed for Vietnam to exploit the future benefits of BRI. There is a need to set up the strategy to mitigate the risk impacts, reduce the risk level, avoid risk, at last turn the risk into opportunities.

Chemical profiles and biological activities of essential oil of Citrus hystrix DC. peels

Do Minh Long,Le Pham Tan Quoc,Tran Thi Phuong Nhung,Vuong Bao Thy,Nguyen Le Quynh Nhu 한국식품저장유통학회 2023 한국식품저장유통학회지 Vol.30 No.3

Essential oil (EO) was extracted from the peel of Citrus hystrix DC. originating from Tinh Bien, An Giang province (Vietnam), using steam distillation. The study aimed to determine some physicochemical properties of Citrus hystrix peel EO (ChpEO), including the acid value (AV), saponification value (SV), ester value (EV), density, specific gravity, and freezing point. The chemical composition was also analyzed by gas chromatography-mass spectrometry (GC-MS). Compounds like β-pinene (30.19%), D-limonene (22.15%), and sabinene (21.37%), with antioxidant and antibacterial properties, had a relatively high content. The EO was also capable of inhibiting the growth of both Gram-positive and Gram-negative bacteria, including Pseudomonas aeruginosa (ATCC 27853), Staphylococcus aureus (ATCC 25923), Salmonella typhimurium (ATCC 13311), and Bacillus cereus (ATCC 11778) specifically.

Exposure to Tobacco Advertising and Promotion among School Children Aged 13-15 in Vietnam - an Overview from GYTS 2014

Tran, Khanh Long,Phung, Xuan Son,Kim, Bao Giang,Phan, Thi Hai,Doan, Thi Thu Huyen,Luong, Ngoc Khue,Pham, Thi Quynh Nga,Nguyen, Tuan Lam,Hoang, Van Minh,Le, Thi Thanh Huong Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.no.sup1

Evidence shows that tobacco advertising and promotion activities may increase tobacco consumption and usage, especially in youth. Despite the regulation on prohibiting advertisement of any tobacco product, tobacco advertisement and promotion activities are still common in Vietnam. This article presents current exposure to tobacco advertising and promotion (TAP) among school children aged 13 to 15 years in Vietnam in 2014 and potential influencing factors. Data from the Global Youth Tobacco Survey 2014 in Vietnam covering 3,430 school aged children were used. Both descriptive and analytical statistics were carried out with Stata 13 statistical software. Binary logistic regression was applied to explain the exposure to TAP among youth and examine relationships with individual factors. A significance level of p<0.05 and sampling weights were used in all of the computations. In the past 30 days, 48.6% of the students experienced exposure to at least 1 type of tobacco advertising or promotion. Wearing or otherwise using products related to tobacco was the most exposure TAP type reported by students (22.3%). The internet (22.1), points of sales (19.2) and social events (11.5) were three places that students aged 13-15 frequently were exposed to TAP. Binary logistic results showed that gender (female vs male) (OR = 0.61, 95%CI: 0.52 - 0.71), susceptibility to smoking (OR = 2.12, 95%CI: 1.53 - 2.92), closest friends' smoked (OR = 1.43, 95%CI: 1.2 - 1.7) and parents smoking status (OR = 2.83, 95%CI: 1.6 - 5.01) were significantly associated with TAP exposure among school-aged children. The research findings should contribute to effective implementation of measures for preventing and controlling tobacco use among students aged 13-15 in Viet Nam.

Factors Affecting Training Quality and Student Satisfaction: An Empirical Study in Vietnam

Duong Thi Hai LE,Long Duc Bao NGUYEN,Chau Le Ngoc PHAN,Tuan Minh VU,Hien Thu PHAN 한국유통과학회 2022 The Journal of Asian Finance, Economics and Busine Vol.9 No.4

The purpose of this study was to determine the factors that influence the training quality of Van Lang University’s Finance Banking faculty (VLU). Another goal was to discover a way to increase training quality and give students the greatest experience possible. To achieve the following goals, qualitative research was used in combination with questionnaires and document reviews. A total of 700 surveys were sent out, with 624 responses. In-depth interviews with 12 graduates were conducted during the qualitative stage to obtain their perspectives on their time at VLU. The impact of five factors (instructor qualification, facility, education program, accessibility, and student interaction) was investigated in this study, and the findings revealed that all of them significantly mediated the relationship with the training quality of VLU’s Finance Banking faculty. The findings show that it is vital to improve the training quality to increase student satisfaction and boost their academic abilities. With the framework from this study, policymakers, researchers, and institutes can cooperate in developing and upgrading the general training quality at higher education institutions in Vietnam. Improving the training quality of a faculty will continue to be a challenge. Therefore, this is a topic that requires continuous research.

Hybrid Content Caching in 5G Wireless Networks: Cloud Versus Edge Caching

Kwak, Jeongho,Kim, Yeongjin,Le, Long Bao,Chong, Song IEEE 2018 IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS Vol.17 No.5

<P>Most existing content caching designs require accurate estimation of content popularity, which can be challenging in the dynamic mobile network environment. Moreover, emerging hierarchical network architecture enables us to enhance the content caching performance by opportunistically exploiting both cloud-centric and edge-centric caching. In this paper, we propose a hybrid content caching design that does not require the knowledge of content popularity. Specifically, our design optimizes the content caching locations, which can be original content servers, central cloud units (CUs) and base stations (BSs) where the design objective is to support as high average requested content data rates as possible subject to the finite service latency. We fulfill this design by employing the Lyapunov optimization approach to tackle an NP-hard caching control problem with the tight coupling between CU caching and BS caching control decisions. Toward this end, we propose algorithms in three specific caching scenarios by exploiting the submodularity property of the sum-weight objective function and the hierarchical caching structure. Moreover, we prove the proposed algorithms can achieve finite content service delay for all arrival rates within the constant fraction of capacity region using Lyapunov optimization technique. Furthermore, we propose practical and heuristic CU/BS caching algorithms to address a general caching scenario by inheriting the design rationale of the aforementioned performance-guaranteed algorithms. Trace-driven simulation demonstrates that our proposed hybrid CU/BS caching algorithms outperform the general popularity based caching algorithm and the independent caching algorithm in terms of average end-to-end service latency and backhaul/fronthaul load reduction ratios.</P>

Distributed Interference Management in Two-Tier CDMA Femtocell Networks

Duy Trong Ngo,Long Bao Le,Le-Ngoc, T.,Hossain, E.,Dong In Kim IEEE 2012 IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS Vol.11 No.3

<P>This paper proposes distributed joint power and admission control algorithms for the management of interference in two-tier femtocell networks, where the newly-deployed femtocell users (FUEs) share the same frequency band with the existing macrocell users (MUEs) using code-division multiple access (CDMA). As the owner of the licensed radio spectrum, the MUEs possess strictly higher access priority over the FUEs; thus, their quality-of-service (QoS) performance, expressed in terms of the prescribed minimum signal-to-interference-plus-noise ratio (SINR), must be maintained at all times. For the lower-tier FUEs, we explicitly consider two different design objectives, namely, throughput-power tradeoff optimization and soft QoS provisioning. With an effective dynamic pricing scheme combined with admission control to indirectly manage the cross-tier interference, the proposed schemes lend themselves to distributed algorithms that mainly require local information to offer maximized net utility of individual users. The approach employed in this work is particularly attractive, especially in view of practical implementation under the limited backhaul network capacity available for femtocells. It is shown that the proposed algorithms robustly support all the prioritized MUEs with guaranteed QoS requirements whenever feasible, while allowing the FUEs to optimally exploit the remaining network capacity. The convergence of the developed solutions is rigorously analyzed, and extensive numerical results are presented to illustrate their potential advantages.</P>